Research Articles
panchromatic luminous efficiency was
7 ± 3%. Theoretical estimates underthese conditions range from 5.6−13.2%(10).
Calibrated video observations provided a trajectory and pre-atmosphericorbit (Table 1) (SM Sect. 1.1). The
fireball was first recorded at 97 km
altitude, moving at 19.16 ± 0.15 km/s
Olga P. Popova,1 Peter
Jenniskens,2,35* Vacheslav Emel’yanenko6,4
and entry angle 18.3 ± 0.2° with respect
4
Anna Kartashova1, Eugeny Biryukov, Sergey Khaibrakhmanov,to the horizon, which is slightly fasterValery Shuvalov, Yurij Rybnov,1 Alexandr Dudorov,6 Victor I.
than reported earlier (11). Combined
7892
Grokhovsky2 , Dmitry D. Badyukov, Qing-Zhu Yin, Peter S. Gural,with the best kinetic energy estimate, an
Jim Albers, Mikael Granvik,10 Läslo G. Evers,11,12 Jacob Kuiper,11
entry mass of 1.3 × 107 kg (with a facVladimir Kharlamov15,1 Andrey Solovyov,13 Yuri S. Rusakov,14
tor of two uncertainty) and a diameter
Stanislav Korotkiy, 7Ilya Serdyuk,16 Alexander
V.
Korochantsev,8
of 19.8 ± 4.6 m is derived, assuming a
Michail Yu Larionov, Dmitry Glazachev,1 Alexander E. Mayer,6spherical shape and the meteoriteGalen Gisler9 ,17 Sergei V. Gladkovsky,18 Josh Wimpenny,9 Matthew
derived density of 3.3 g/cm3 based on
99
E. Sanborn, Akane Yamakawa, Kenneth L. Verosub, Douglas J.
x-ray computed tomography (SM Sect.
Rowland,1920,21
Sarah Roeske,9 Nicholas
W. Botto23,22,9 Jon M.
4.2, table S16).
22
23,22
Friedrich,MichaelE.
Zolensky, Loan Le,
DanielRoss,
Size and speed suggest that a
Karen27,28
Ziegler,24 Tomoki
Nakamura,25 Insu Ahn,25 Jong Ik Lee,26 Qinshockwave
first developed at 90 km.
Zhou,
Xian-Hua
Li,28 Qiu-Li Li,28 Yu Liu,28 Guo-Qiang Tang,28
Observations show that dust formation
29
3
7
Takahiro Hiroi7, Derek Sears, Ilya A.
Weinstein, Alexander S.
and fragmentation started around 83 km
Vokhmintsev, Alexei
V.
Ishchenko,7 Phillipe Schmitt-Kopplin,30,31
and accelerated at 54 km (figs. S16 andNorbert Hertkorn,30 Keisuke Nagao,32 Makiko K. Haba,32 Mutsumi
S22). Peak radiation occurred at an
33
34
Komatsu, Takashi Mikouchi (the Chelyabinsk Airburst
altitude of 29.7 ± 0.7 km at 03:20:32.2
Consortium)± 0.1s UTC (SM Sect. 1.1-2), at whichtime spaceborne sensors measured a*Corresponding author. E-mail: Petrus.M.Jenniskens@nasa.gov
meteoroid speed of 18.6 km/s (5).
Author affiliatons are shown at the end of the text.
Fragmentation left a thermally emitting
debris cloud in this period, the final
The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 wasburst of which occurred at 27.0 km
the largest airburst on Earth since the 1908 Tunguska event, causing a natural
altitude (Fig. 1), with dust and gas setdisaster in an area with a population exceeding one million. Because it occurred intling at 26.2 km with distinctly higher
an era with modern consumer electronics, field sensors, and laboratory techniques,billowing above that location (fig. S22).
unprecedented measurements were made of the impact event and the meteoroid
The dust cloud split in two due tothat caused it. Here, we document the account of what happened, as understoodbuoyancy of the hot gas, leading to twonow, using comprehensive data obtained from astronomy, planetary science,cylindrical vortices (12).
geophysics, meteorology, meteoritics, and cosmochemistry, and from social
Compared to the much larger Tunscience surveys. A good understanding of the Chelyabinsk incident provides aguska event (2, 3), Chelyabinsk was
unique opportunity to calibrate the event, with implications for the study of nearonly on the threshold of forming a
Earth objects and developing hazard mitigation strategies for planetary protection.
common shock wave around the fragments when it broke at peak brightness(SM Sect. 1.2). Fragments were spatialChelyabinsk Oblast experienced an impact that was 100 times morelyisolatedenoughtobeefficiently
decelerated, avoiding the transfer ofenergetic than the recent 4 kT of TNT equivalent Sutter’s Mill (1). This
was the biggest impact over land since the poorly observed Tunguska momentum to lower altitudes and resulting in less damage when theimpact in 1908, for which kinetic energy estimates range from 3−5 (2) to blast wave reached the ground.
10−50 MT (3). From the measured period of infrasound waves circum
traveling the globe (4), an early estimate of ~470 kT was derived for
Chelyabinsk (5). Infrasound data from Russia and Kazakhstan provide
570 ± 150 kT; see supplementary materials (SM) Section 1.4 (6). Spaceborne visible and near-infrared observations (7) recorded a total irradiated energy of 90 kT (5, 8), corresponding to a kinetic energy of 590 ± 50
kT using the calibration by Nemtchinov et al. (9). All values are uncertain by a factor of two because of a lack of calibration data at those highenergies and altitudes.
The manner in which this kinetic energy was deposited in the atmosphere determined what shock wave reached the ground. Dash-cam andsecurity camera videos of the fireball (Fig. 1) provide a lightcurve withpeak brightness of -27.3 ± 0.5 magnitude (Fig. 2) (SM Sect. 1.2). The
integrated lightcurve is consistent with other energy estimates if theDamage Assessment
In the weeks following the event, 50 villages were visited to verify theextent of glass damage. The resulting map (Fig. 3) demonstrates that theshockwave had a cylindrical component, extending furthest perpendicular to the trajectory. There was little coherence of the shockwave in theforward direction, where the disturbance was of long duration, shaking
buildings and making people run outside, but causing no damage.
The strength of this shockwave on the ground was modeled (SMSect. 2.4) assuming that an overpressure of ΔP > 500 Pa was required(13). A 520 kT event, with detonations spread over altitudes ranging
from 34−27 km and 24−19 km, would cause damage out to a distance of
120 km with the observed shape (Fig. 3). The fragments that penetrated/ http://www.sciencemag.org/content/early/recent / 7 November 2013 / Page 1 / 10.1126/science.1242642

Downloaded from www.sciencemag.org on November 13, 2013

Chelyabinsk Airburst, Damage
Assessment, Meteorite Recovery, andCharacterization

below 27 km must have contributed to the damage in order to match theshock wave arrival times (SM Sect. 2.4).
The number of houses damaged per 1,000 inhabitants (table S11)
(SM Sect. 2.3) falls off with distance from the airburst source (r) as r–2.6 ±1.2, with overpressure calculated to fall off as r−2.4 (fig. S39). In Chelyabinsk itself, 3,613 apartment buildings (about 44%) had shattered andbroken glass, but these were not evenly distributed in the city (fig. S37).
Sharp sounds heard following the shockwave also point to the fragmentation causing a complicated distribution of pressure. Structural damage
included the collapse of a zinc factory roof.
Directly below the fireball’s path, the shock wave was strong enoughto blow people off their feet. In Yemanzhelinsk, window frames facing
the trajectory were pushed inwards, and suspended ceilings were sucked
down above broken windows (fig. S36G). There was no structural damage to buildings, other than a statue of Pushkin inside the local library,cracked by a blown out window frame. Cracks in walls were documented in nearby Baturinsky and Kalachevo.
Electrophonic sounds were heard (SM Sect. 1.6), but there was noevidence of an Electromagnetic Pulse (EMP) under the track in neighboring Emanzhelinka. Due to shock wave induced vibrations, electricity
and cell phone connectivity was briefly halted in the Kunashaksky district at the far northern end of the damage area. The gas supply was
briefly interrupted in some districts due to valves reacting to the vibrations.
People found it painful to look at the bright fireball, but glancing
away prevented lasting eye damage. Of 1,113 respondents to an internet
survey who were outside at the time, 25 were sunburned (2.2%), 315 felt
hot (28%) and 415 (37%) warm (SM Sect. 2.2). Mild sunburns werereported throughout the survey area (table S7), reflecting the fact thatUV flux density falls off as ~r−2. In Korkino, 30 km from the point ofpeak brightness, one resident reported getting a mild sunburn on theface, followed by loss of skin flakes. Such effects occur at a minimum
erythema dose of ~1,000 J/m2 (14) of 290-320 nm radiation (mostly UVB). Assuming 6,000 K radiation (9), the calculated dose would havebeen ~200 J/m2 at Korkino. Ground-reflectance of UV light by snow
may have further increased the dose.
Out of the total 1,674 collected internet queries, 374 mention 452
body injuries or inconveniences (SM Sect. 2.2). Of those, 5.3% reported
sunburn, 48% eyes hurt, and 2.9% felt retinal burns. Because of theshock wave, 6.4% reported a concussion or mental confusion, upset, or
exhaustion as a result of excessive stress. Flying glass and falling building debris affected a relatively small fraction of respondents: 4.8% reported cuts and 2.9% reported bruises, but no broken bones werereported.
The percentage of people asking for medical assistance (table S10)
dropped with distance according to r–3.2 ± 0.5 (SM Sect. 2.1). The majority
of injuries (1,210) took place in the densely populated Chelyabinsk city,
but the highest fraction of people asking for assistance was near the trajectory track in the Korkinsky district (0.16%).
Meteorite Recovery
Shock radiation contributed to surface heating and ablation, but did notcompletely evaporate all fragments of Chelyabinsk, unlike in the case of
Tunguska (3). Meteorites of ~0.1 g fell near Aleksandrovka close to thepoint of peak brightness, masses of ~100 g fell further along the trajectory near Deputatskiy, and at least one of 3.4 kg fell near Timiryazevskiy.
One hit the roof of a house in Deputatskiy (fig. S46). Falling-spheremodels suggest they originated at 32-26 km altitude (fig. S52), where themeteor model shows rapid fragmentation (fig. S18C). The location of themeteorites is consistent with prevailing NW winds of 5−15 m/s (fig.
S24). An estimated 3,000−5,000 kg fell in this area (SM Sect. 3.1).
Two main fragments survived the disruption at 29.7 km. They flaredaround 24 km, with one falling apart at 18.5 km, and the other remaining

luminous down to 13.6 km (Fig. 1 and fig. S15). Lightcurve modeling(SM Sect. 1.2) suggests that from this material another ~1 ton in larger
fragments up to 100−400 kg in mass reached the ground. A 7-m sizedhole was discovered in 70-cm thick ice on Lake Chebarkul (fig. S53A),
in line with the trajectory (SM Sect. 1.1). A lakeshore video security
camera, pointed to the site, recorded the impact (fig. S53B). Small meteorite fragments were recovered over an area up to 50 m from the impact
location (Fig. 4C). Impact models (figs. S18 and S54) suggest a200−1,000 kg meteorite would be required to create such a hole. A massof ≥570 kg was recovered from the lakebed (fig. S53C).
The combined 4-6 t of surviving meteorites is only 0.03−0.05% of
the initial mass. 76% of the meteoroid evaporated, with most of the remaining mass converted into dust (SM Sect. 1.3). Witnesses reported
smelling “sulfur” and burning odors over a wide region concentrated
near the fireball trajectory, starting about an hour after the fireball andlasting through much of the day (SM Sect. 1.5) (fig. S34).
Characterization of Recovered Meteorites
The unusually effective fragmentation and small surviving mass may
have been caused by structural and material weakness. The asteroid had
a lower compressive strength than the ~330 MPa measured for recovered, surviving meteorites (Section S4.1). The lightcurve (Fig. 2) ismodeled with fragmentation starting at a low 0.2 MPa dynamic pressure,but tolerating higher pressure with decreasing fragment size. This issimilar to other meteorite falls, where initial weakness was attributed tomacroscopic cracks or microscopic porosity (15). For Chelyabinsk,
however, the physical weakness is not microporosity related. X-ray
computed tomography (SM Sect. 4.2) revealed a degree of compaction
consistent with the lack of intragranular porosity typical of LL chondrites (16).
Some laboratory broken meteorites fragmented along shock veins(fig. S55), a possible weakness in the material that could have contributed to the abundant dust formation. The meteorite is composed of a breccia (17) of mildly shocked lighter clasts and moderately shocked darker
clasts with abundant thin to cm-wide shock melt veins (Fig. 4A) (SMSect. 4.4). A peculiar feature is that some shock veins exhibit a metal
layer located ~20 microns inside the vein, which follows the outer contours of the vein (Fig. 4B), indicating that metal initially segregated fromthe most rapidly solidifying rims of the vein. This could contribute to
weakness. Metal-rich tendrils also project outward from the vein.
The mineral compositional ranges (SM Sect. 4.4) are slightly larger
than those reported before (18), but still compatible with a classification
as LL5, shock stage S4 (19). The classification as LL chondrite is substantiated by oxygen and chromium isotope studies (SM Sect. 4.5−4.7),
which put the meteorite near the L-end of the LL field (20, 21) (Fig. 4D
and fig. S68). Iron content and oxidation state also support the LL chondrite classification (Fig. 4E and fig. S58). Rare Earth element abundances are more similar to L chondrites (Fig. 4F and table S18), while one
measured reflectance spectrum better matches that of H chondrites (fig.
S72).
The Chelyabinsk (LL) parent body experienced a significant thermal
and/or collision resetting event 115 ± 21 Ma after formation of the Solar
System (25), not experienced by most other LL chondrites, possibly due
to a significant impact event near its site of origin on the parent body.
The phosphate U-Pb age is 4,452 ± 21 Ma (SM Sect. 4.8) (fig. S70),
much younger than the majority of other ordinary chondrites phosphateages dated by conventional TIMS methods (22, 23). Perhaps one otherpiece of evidence for this is the 4.48 ± 0.12 Ga Pb-Pb isochron age ofphosphates in a granite-like fragment found in the LL3-6 chondrite regolith breccia Adzhi-Bogdo (24), an observed fall in Mongolia in 1949.
Chelyabinsk shows a common orientation of metal grains indicating
an impact-related petrofabric (fig. S59), stronger than that seen in any
other ordinary chondrite of any shock stage (26) (fig. S60). This petro-/ http://www.sciencemag.org/content/early/recent / 7 November 2013 / Page 2 / 10.1126/science.1242642

fabric probably reflects the most recent extraterrestrial shock event experienced by the Chelyabinsk meteoroid. The magnetic susceptibility value
is at the upper end of the range for LL type (fig. S61) (27), closer to L
type chondrites, suggestive of higher metal content in Chelyabinsk thana typical LL chondrite. However, detailed analysis of the remanent magnetization suggests that a shock event or the conditions of atmosphericentry led to significant resetting of the remanence (SM Sect. 4.3).
Recent meteoroid heating events are normally recorded by thermoluminescence (TL) (SM Sect. 4.10). In this case, the induced TL level of
Chelyabinsk is lower than other petrographic type 5 or 6 chondrites,
possibly because shock metamorphism to the level of S4 (30-35 GPa)(fig. S79) destroyed feldspar, the mineral phase responsible for the thermoluminescence signal (28). Atmospheric heating did not cause loss ofnatural TL signal, the steep thermal gradient being consistent with a verythin fusion crust on the measured samples (29). The natural TL value isconsistent with the meteoroid having been heated at a perihelion distanceof 0.6−0.8 AU (Table 1).
The shock did not remove all organic matter from the meteorite.
Methanol-soluble polar organic compounds (Sect. S4.11) were detected
in impact melt vein and chondrite fractions using electrospray ionization
ion cyclotron resonance Fourier-Transform mass spectrometry (30). Out
of more than 18,000 resolved mass peaks, 2,536 could be assigned tocompounds containing C, H, N, O, S. The organic signature is typical ofother shocked LL chondrites, showing a higher abundance of oxygenand nitrogen atoms in the impact melt (fig. S83). The presence of oxygenated sulfur is indicated by CHOS compounds containing on average
3 more oxygen atoms than CHO and CHNO compounds. The highabundance of CHOS compounds in a homologous series across the entire mass range testifies that most of these did not result from terrestrial
contamination.
Impact shock induced fracturing on the Chelyabinsk parent bodywas followed by melting of metal and sulfides, which are pressuredriven through the meteorite. There are cases where this increased a
meteorite’s mechanical strength, the residual heat facilitating the process. However, in the case of Chelyabinsk, the production of cracks
weakened the meteorite material more than shock melting increased its
strength.
Source and Evolution of the Chelyabinsk Meteoroid
Chelyabinsk adds an LL5 type meteorite to a short list (SM Sect. 1.1) of
18 differently typed meteorites with known pre-atmospheric orbits (1).
Only 8.2% of falls are LL chondrites (31). The Chelyabinsk meteorite isof particular interest because it is of the same type as asteroid Itokawa,from which samples were collected by the Hayabusa Mission (32). Indeed, both Itokawa and Chelyabinsk have similar low-inclined lowsemi-major axis orbits (Table 1), which, according to one model (33),
imply a 62%, 11%, and 25% probability for Chelyabinsk (and 71%, 0%,
and 29% probability for Itokawa) of originating from the secular ν6 resonance, the 3:1 mean-motion resonance, and the Intermediate Mars
Crosser region, respectively. Multiplying these probabilities, assuming
all LL chondrites enter the near Earth object region through the same
escape route, there is now an 86% probability that they originated from
ν6. This supports the hypothesis (34) that they originated from the innerpart of the LL-type (35) Flora asteroid family, which straddles the ν6resonance in 1.6−7.7° inclined orbits (36).
As a group, LL chondrites have a cosmic ray exposure age peaking
at ~17 Ma (34). Chelyabinsk, on the other hand, was exposed only since~1.2 Ma (SM Sect. 4.12). The responsible breakup that first exposed the
Chelyabinsk meteoroid surface to cosmic rays was not likely part of theongoing collision cascade in the asteroid main belt that followed theformation of the Flora family. Although fast pathways exist that canbring meteoroids from all three resonances into a Chelyabinsk-like orbit
in about 0.2 Ma, such cases are rare (table S6). More likely, Chelyabinsk

was exposed only since being ejected from the resonance, due to
breakup from either thermal stresses, rotational spin-up, or from tidal
forces in terrestrial planet encounters. The required structural weakness
may have come from macroscopic cracks or from a weakly consolidated
rubble pile morphology.
If tidal forces disrupted the Chelyabinsk meteoroid (37), events were
set in motion 1.2 Ma ago during what was likely an earlier close encounter with Earth, when a 20-m sized chunk of subsurface Flora-family
parent body rubble, rich in shock veins, separated from a larger object.
The rest of that rubble could still be part of the near-Earth object population.
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Acknowledgments: The Russian Academy of Sciences field study of the
Chelyabinsk airburst was supported by the Institute for Dynamics ofGeospheres and grants of the Federal Targeted Program “Scientific and
Educational Human Resources of Innovation-Driven Russia” and the RAS
Presidium Program “Fundamental Problems of Investigation and Explorationof the Solar System”. The office of Chelyabinsk Oblast Governor Mikhail
Yurevich provided assistance. S. Petukhov and I. Talyukin from the Universe
History Museum in Dedovsk contributed samples, as did M. Boslough of
Sandia National Laboratories. U. Johann (Astrium Satellites GmbH)calculated the Chebarkul hole position from Pléiades 1A satellite
observations. D. F. Blake provided use of a petrographic microscope. P.J.
acknowledges support from the NASA Near Earth Object Observation
Program, Q.Z.Y. and M.E.Z. from the NASA Cosmochemistry Program, andM.G. by the Academy of Finland.

1 July 2013; accepted 28 October 2013
Published online 7 November 201310.1126/science.1242642
Author Affiliations
1

Institute for Dynamics of Geospheres of the Russian Academy of
Sciences, Leninsky Prospect 38, Building 1, Moscow, 119334, Russia.
2
SETI Institute, 189 Bernardo Ave, Mountain View, CA 94043, USA.
3
NASA Ames Research Center, Moffett Field, Mail Stop 245-1, CA 94035,
4USA. Institute of Astronomy of the Russian Academy of Sciences,5
Pyatnitskaya 48, Moscow, 119017, Russia. Department of Theoretical
Mechanics, South Ural State University, Lenin Avenue 76, Chelyabinsk,
6454080, Russia. Chelyabinsk State University, Bratyev Kashirinyh Street
7129, Chelyabinsk, 454001, Russia. Institute of Physics and Technology,
Ural Federal University, Mira Street 19, Yekaterinburg, 620002, Russia.
8
Vernadsky Institute of Geochemistry and Analytical Chemistry of the
9
RAS, Kosygina Street 19, Moscow, 119991, Russia. Department of Earthand Planetary Sciences, University of California at Davis, Davis, CA
1095616, USA. Department of Physics, University of Helsinki, P. O. Box
1164, 00014 Helsinki, Finland. Koninklijk Nederlands Meteorologisch
12
Instituut, P. O. Box 201, 3730 AE De Bilt, Netherlands. Department ofGeoscience and Engineering, Faculty of Civil Engineering andGeosciences, Delft University of Technology, P.O. Box 5048, 2600 GA
13Delft, Netherlands. Tomsk State University, Lenina Prospect 36, Tomsk,
14634050 Russia. Research and Production Association “Typhoon”, fl. 2, 7
15
Engels Street, Obninsk, 249032, Russia. Support Foundation for
16
Astronomy “Ka-Dar”, P.O. Box 82, Razvilka, 142717 Russia. Scienceand Technology Center of the Social and Youth Initiatives Organization, 317
12-63 Udal’tsova Street, Moscow, 119415, Russia. University of Oslo,18
Physics Building, Sem Saelands Vel 24, 0316 Oslo, Norway. Institute ofEngineering Sciences Urals Branch of the Russian Academy of Sciences,19
Komsomolskaya Street 34, Yekaterinburg, 620049, Russia. Center for
Molecular and Genomic Imaging, University of California, Davis, Davis,
20
CA 95616, USA. Department of Earth and Planetary Sciences, American
21
Museum of Natural History, New York, NY 10024, USA. Department of22
Chemistry, Fordham University, Bronx, NY 10458, USA. Astromaterials
Research and Exploration Science, NASA Johnson Space Center,23
Houston, TX 77058, USA. Jacobs Technology, 2224 Bay Area
24
Boulevard, Houston TX 77058, USA. Institute of Meteoritics, University
25
of New Mexico, Albuquerque, NM 87131–0001, USA. Department ofEarth and Planetary Materials Science, Tohoku University, Aramaki, Aoba,
26
Sendai, Miyagi 980-8578, Japan. Division of Polar Earth-System
Sciences, Korea Polar Research Institute, 26 Songdomi rae, Yeonsu-gu,
27
Incheon 406-840, Korea. National Astronomical Observatories, Beijing,
28
Chinese Academy of Sciences, Beijing 100012, China. State Key
Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics,
29
Chinese Academy of Sciences, Beijing 100029, China. Department of
Geological Sciences, Brown University, Providence, RI 02912, USA.
30
Analytical BioGeoChemistry, Helmoltz Zentrum Muenchen, Ingoldstäter
31
Landstrasse 1, D-85764 Obeschleissheim, Germany. Technical
University Muenchen, Analytical Food Chemistry, Alte Akademie 10,3285354 Freising, Germany. Geochemical Research Center, The
University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
33
Waseda Institute for Advanced Study, Waseda University, 1-6-1
34
Nishiwaseda, Shinjuku, Tokyo 169-8050, Japan. Department of Earthand Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku,
Tokyo 113-0033, Japan.

Supplementary Materials
www.sciencemag.org/cgi/content/full/science.1242642/DC1
Supplementary Text
Figs. S1 to S87
Tables S1 to S24
References (42–157)/ http://www.sciencemag.org/content/early/recent / 7 November 2013 / Page 7 / 10.1126/science.1242642

Table 1. Atmospheric trajectory and pre-atmospheric orbit for the Chelyabinsk meteoroid, with 2 standard deviation uncertainties. Angular elements are for equinox J2000.0.
Atmospheric trajectory
Hb (beginning height, km)

Chelyabinsk
97.1 ± 1.6

Pre-atmospheric orbit
TJ (Tisserand’s parameter)a (semimajor axis, AU)e (eccentricity)q (perihelion distance,AU)ω (argument of perihelion, °)Ω (longitude of ascending node, °)i (inclination, °)Chelyabinsk
3.87 ± 0.24

Itokawa
4.90

Hm (peak brightness, km)
Hf (disruption, km)
He (end height, km)

29.7 ± 1.4
27.0 ± 1.4
13.6 ± 1.4

1.76 ± 0.16
0.581 ± 0.018
0.739 ± 0.020

1.324
0.280
0.953

V∞ (entry speed, km/s)

19.16 ± 0.30

108.3 ± 3.8

162.8

h (entry elevation angle, °)18.3 ± 0.4

326.4422 ± 0.0028

69.1

az (entry azimuth angle fromSouth, °)Vg (geocentric entry speed,km/s)
Rag (geocentric right ascension of radiant, °)Decg (geocentric declinationof radiant, °)283.2 ± 0.4

4.93 ± 0.48

1.6

2.78 ± 0.20

1.70

333.2 ± 1.6

Q (aphelion distance,AU)Tp (perihelion time)

2012-12-31.9 ± 2.0

2013-07-10.8+0.3 ± 1.8

Epoch (ET)2013-02-15.139

2013-04-18.0

15.3 ± 0.4/ http://www.sciencemag.org/content/early/recent / 7 November 2013 / Page 8 / 10.1126/science.1242642

Fig. 1. Meteoroid fragmentation stages in video taken by
Aleksandr Ivanov in Kamensk-Uralskiy. (A) Fireball justbefore peak brightness, at the moment when camera gain
first adjusted. (B) End of main disruption. (C) Onset of
secondary disruption. (D) End of secondary disruption, main
debris cloud continues to move down. (E) Two main
fragments remain. (F) Single fragment remains. (G)Thermally emitting debris cloud at rest with atmosphere. (H)Final fragment continues to penetrate. Meteor moved behinddistant lamp posts. (I and J) Detail of the thermal emission
from a photograph by Mr. Dudarev (I) and Marat
Ahmatvaleev (J), after sky subtraction with high-pass filterand contrast enhancement. Altitude scale is uncertain by±0.7 km.

Fig. 2. Fireball visual magnitude irradiance lightcurve,
normalized to 100 km distance. The bold dashed line
shows the model fit to the lightcurve (SM Sect. 1.2), with thinlines showing total mass of all fragments passing a given
altitude (kg) and the altitude dependent rate of energy−1
deposition as a fraction of the original kinetic energy (km ).

/ http://www.sciencemag.org/content/early/recent / 7 November 2013 / Page 9 / 10.1126/science.1242642

Fig. 3. Map of glass damage on the ground with models of overpressure.
Field survey data are shown in solid orange circles for reported damage and open
black circles for no damage, while solid red circles are the most damaged villages
in each district reported by the government. Each point, irrespective of population
density, represents one of many villages or city districts scattered throughout thearea. Model contours (with progressive grey scale) represent kinetic energies andover pressures from inside out: 300 kT Δp > 1,000 Pa, 520 kT Δp > 1,000 Pa, 300
kT Δp > 500 Pa, and 520 kT Δp > 500 Pa, respectively. Also shown are thelocations of meteorite finds (yellow points) and the ground-projected fireballtrajectory (black line), moving from 97 km altitude right to 14 km altitude left. Whiteshows the fireball brightness on a linear scale.

/ http://www.sciencemag.org/content/early/recent / 7 November 2013 / Page 10 / 10.1126/science.1242642

Fig. 4. Meteorite material properties, chemical and isotopic compositions. (A)Chelyabinsk meteorite (diameter ~4 cm) showing shock veins. (B) Fe element map of
a shock vein. Note the metal layer (shown in green) located ~20 microns inside the17vein. (C) Meteorite fragments recovered from the ice covered lake Chebarkul. (D) Δ O
versus Fa mol% of olivine in Chelyabinsk, compared to other ordinary chondrites oftype H, L, and LL (38). Fa is defined as mole ratio of Fe/(Fe+Mg) in olivine. Average17
Δ O values from UNM (1.15 ± 0.06‰) and from KOPRI (1.31 ± 0.04‰) for
Chelyabinsk likely reflect indigenous heterogeneity in oxygen isotopes. Solid symbols
are Fa number measured in this study (SM Sect. S4.3), while open symbols are from
(18). (E) Ratio plots of the three major elements (Mg, Si, Fe; together with oxygen>90% of mass) for Chelyabinsk and the main chondrite groups. The bulk Earth andbulk silicate Earth compositions were taken from (39), chondrite compositions from(40). (F) CI chondrite normalized rare earth elemental pattern of Chelyabinsk
compared to the average chondrite group compositions of (38, 41).

/ http://www.sciencemag.org/content/early/recent / 7 November 2013 / Page 11 / 10.1126/science.1242642

www.sciencemag.org/cgi/content/full/science.1242642/DC1

Supplementary Materials for
Chelyabinsk Airburst, Damage Assessment,
Meteorite Recovery, and Characterization
Olga P. Popova, Peter Jenniskens,* Vacheslav Emel’yanenko, Anna Kartashova,
Eugeny Biryukov, Sergey Khaibrakhmanov, Valery Shuvalov, Yurij Rybnov,
Alexandr Dudorov, Victor I. Grokhovsky, Dmitry D. Badyukov, Qing-Zhu Yin,Peter S. Gural, Jim Albers, Mikael Granvik, Läslo G. Evers, Jacob Kuiper,
Vladimir Kharlamov, Andrey Solovyov, Yuri S. Rusakov, Stanislav Korotkiy,
Ilya Serdyuk, Alexander V. Korochantsev, Michail Yu Larionov, Dmitry Glazachev,
Alexander E. Mayer, Galen Gisler, Sergei V. Gladkovsky, Josh Wimpenny,
Matthew E. Sanborn, Akane Yamakawa, Kenneth L. Verosub, Douglas J. Rowland,
Sarah Roeske, Nicholas W. Botto, Jon M. Friedrich, Michael E. Zolensky,
Loan Le, Daniel Ross, Karen Ziegler, Tomoki Nakamura, Insu Ahn,
Jong Ik Lee, Qin Zhou, Xian-Hua Li, Qiu-Li Li, Yu Liu,
Guo-Qiang Tang, Takahiro Hiroi, Derek Sears, Ilya A. Weinstein,Alexander S. Vokhmintsev, Alexei V. Ishchenko, Phillipe Schmitt-Kopplin,
Norbert Hertkorn, Keisuke Nagao, Makiko K. Haba, Mutsumi Komatsu,
Takashi Mikouchi (the Chelyabinsk Airburst Consortium)*To whom correspondence should be addressed. E-mail: Petrus.M.Jenniskens@nasa.gov
Published 7 November 2013 on Science Express
DOI: 10.1126/science.1242642

This PDF file includes:

Supplementary Text
Figs. S1 to S87
Tables S1 to S24
References
Other Supplementary Material for this manuscript includes the following:(available at www.sciencemag.org/cgi/content/full/science.1242642/DC1)
Movie S1

O. P. Popova, et al., Chelyabinsk Airburst, Damage Assessment,
Meteorite Recovery and Characterization. Science 342 (2013).

Table of Content
1. Asteroid Orbit and Atmospheric Entry
1.1. Trajectory and Orbit.............................................................................................................

3

Time of Entry....................................................... ..............................................................

3

Astrometry of Video Records............................................................................................

4

Shadows in Video Records................................................................................................. 11
Trajectory and Orbit.......................................................................................................... 13
Preatmospheric Orbit........................................................................................................ 18
Final Fragments.................................................................................................................. 19
Model of Meteoroid Orbital Dynamics............................................................................ 20
1.2. Lightcurve and Meteor Model ............................................................................................. 22
Lightcurve........................................................................................................................... 22
Meteor Model...................................................................................................................... 24
1.3. Thermal Radiation and the Smoke Cloud............................................................................. 30
Prevailing Winds and Train Drift..................................................................................... 34
1.4. Infrasound Data.................................................................................................................... 39
1.5. Witness Reports: Smells........................................................................................................ 45
1.6. EMP and Electrophonic Sounds........................................................................................... 53
2. Damage Assessment
2.1. Injuries.................................................................................................................................. 55
2.2. Heat and Sunburn................................................................................................................. 57
2.3. Glass Damage....................................................................................................................... 58
2.4. Model of the Shockwave........................................................................................................ 62
Blast Wave Arrival Times................................................................................................. 69
2.5. Structures Hit by Falling Meteorites.................................................................................... 74
3. Meteorite Recovery
3.1. Recovered Meteorites............................................................................................................ 75
Meteorite Recovery from Snow......................................................................................... 80
Mass Distribution of Fallen Meteorites and Total Fallen Mass..................................... 81
Chebarkul Lake Meteorites............................................................................................... 84
Model of Chebarkul Lake Impact.................................................................................... 87

4. Meteorite Characterization
4.1. Mechanical Properties.......................................................................................................... 89
4.2. X-ray Computed Tomography............................................................................................... 90
Metal Grain Orientations.................................................................................................. 94
4.3. Magnetic Susceptibility and Paleomagnetism...................................................................... 96
4.4. Petrography and Mineralogy................................................................................................ 98
4.5. Major, Minor, and Trace Element Analyses....................................................................... 103
4.6. Ultrahigh Precision Cr Isotope Analyses........................................................................... 106
4.7. Oxygen Isotope Analyses.................................................................................................... 108
4.8. U-Pb Age............................................................................................................................. 110
4.9. Reflection Spectroscopy...................................................................................................... 114
4.10. Thermoluminescence......................................................................................................... 116
4.11. Electrospray Ionization Ultra-High Resolution Mass Spectrometry................................ 123
4.12. Noble Gas Isotopes........................................................................................................... 128
References and Notes only cited in Supporting Materials Section (42-157)....................... 134

2

Introduction to Supplementary Materials
This document contains supplementary material to the research article "Chelyabinsk Airburst,
Damage Assessment, Meteorite Recovery and Characterization" (Popova et al., Science 342,
2013), and is provided online as a Supporting Online Materials document (SOM). It contains
collected data, methods of analysis, and a more in-depth interpretation of results. Individual
sections address the asteroid orbit and atmospheric entry (SOM Sect. 1), damage assessment(Sect. 2), meteorite recovery (Sect. 3), and meteorite characterization (Sect. 4). The main
contributors to each sub-section are identified.
1. Asteroid Orbit and Atmospheric Entry
1.1. Trajectory and Orbit(Contributed by: P. Jenniskens, P. S. Gural, J. Albers, A. Kartashova, E. Biryukov, and
V. Emel'yanenko)
Time of entry
Footage from 34 video security cameras in Chelyabinsk Oblast (the administrative term for theregion) were recorded at 10 frames-per-second on a single time-calibrated server. Cameras werepointed downward on traffic and do not show the fireball itself. On February 15, 2013, sunrise in
Chelyabinsk was at 03:17 Universal Time (UT). The landscape initially brightened to a peak at
03:20:29.8±0.1 UT, at which time the color temperature of the light lowered to a more yellow
hue. Brightness continued to increase to a peak between 03:20:31.2 and 03:20:32.2 UT, different
for different cameras because of gain adjustments. Brightness abruptly decreased at 03:20:32.65
UT, when the landscape became bathed in a reddish color. There was subsequently a brief
increase of light with a more bluish tone peaking at 03:20:33.4 UT.
Table S1. Time and location of key events from the analyses of video records.
EventFirst detected
First peak
Main peakEnd of thermal cloud formation
Secondary disruption
Tertiary disruption
Last detected
Thermal cloud comes to rest

Time (s, UT)(±0.1)
3:20:20.8
3:20:29.8
3:20:32.2
3:20:32.65
3:20:33.4
3:20:34.7
3:20:36.8~3:20:37

Latitude (º)(±0.018)54.44554.76454.84554.85954.87654.90554.93154.864

3

Longitude(º) (±0.030)
64.56562.10961.41261.27861.12860.86560.62561.240H (km)(±0.7)
97.1
43.9
29.7
27.0
23.9
18.5
13.6
26.2

V (km/s)(±0.16)
19.16
19.2
19.2
19.2
16.8
12.1
4.9
-.-

Astrometry of Video Records
Times were not synchronized in most of the other >400 videos posted on the internet, many fromdashboard-mounted video cameras (dash-cam). Eight perspectives were calibrated during a twoweek field investigation (March 9 - 24, 2013), by taking star background images at known times(Table S2). The Snezhinsk video was calibrated by local resident Gennadij Ionov on April 15th,
and the Kamensk-Uralskiy video by Artem Burdanov of Ural Federal University on June 10th.

Fig. S1. Location of camera sites (meteor filmed - red; meteor shadow recorded - blue) used toreconstruct the trajectory.
Table S2. Star-background calibrated video camera sites. The video frame rate is in frames per second(fps). O-C is observed minus calculated dispersion in star positions for fitted coordinate frame.

#

Site

Early part:
Pervomayskiy
KorkinoAll, but from a distance:
3 Beloretsk
4 Snezhinsk
5 Kamensk-Uralskiy
Late part:
6 Chelyabinsk Savina
Street7 Chebarkul
8 Yemanzhelinsk
Train (late part):
9 Yemanzhelinsk bus depot
10 Etkul
1
2

Latitude(ºN)

Longitude Alt.
(ºE)
(m)

Type

Rate
(fps)

O-C
(')

PE
KO

54.87060
54.89089

61.17369
61.39966

275
249

parked carparked car

25
30

0.7
0.4

BE
SN
KU

53.95277
56.07940
56.41500

58.41020
60.74271
61.91858

537
267
170

car, stopped
car, stopped
car, stopped

30
30
30

1.2
1.2
1.2

CS

55.16633

61.44473

223

parked car

25

1.2

CB
YE

54.99510
54.75664

60.40024
61.30380

345
227

parked car
moving car

30
25

0.4
0.9

YB
ET

54.75538
54.82193

61.31534
61.58429

240
234

hand-held
hand-held

30
30

0.3
0.3

4

Fig. S1 shows the location of these sites relative to the fireball trajectory. Calibration images
were taken with a global positioning system (GPS) equipped Nikon D5100 camera with a wide
angle 10-mm f3.5 lens, as well as a Canon EOS 40D camera, also with a 10-mm f3.5 lens. This
provided a mean astrometric accuracy of <1.3' in observed minus calculated (O-C) star position(Table S2). The exposure time was 3-30s, depending on ambient light conditions, with starpositions averaged over that time interval. The EXIF timestamp is the time of writing to disk.

Fig. S2. Chelyabinsk Savina Street video by Alexandr Yakushenkov; (A) Frame at peak brightness, withposition of the meteor inserted in all video frames (B); Application of the Adobe Photoshop lenscorrection (at 3 x 100%) and 150% scaling, then slightly warped (C), to match foreground features in starbackground image (D, E).

The astrometric precision of the meteor trajectory is not determined by the astrometricaccuracy of the star background images, but by how precisely foreground features can bematched. Matching was done by first projecting the centroid of the meteor in each frame onto asingle video frame (when the scene is well illuminated). This image was then distorted to match
the wide-angle star background image (Fig. S2). A near-perfect match was obtained for the5Chelyabinsk Savina Street recording, where many foreground features defined the lens distortionin this dash-cam. The image was matched within about 2 pixels at all positions in the image byapplying three times the standard lens correction and a small warp to align the edges. This image
was taken on March 15th, before leaves sprouted in springtime. The car was parked facing south
and the meteor entered the top of the field of view, moving from left to right, well after the timeof peak brightness at time stamp 9:42:13.20, which is the local time with some time offset.

Fig. S3. In Beloretsk, the directions are well aligned with the direction to the background mountains inthis video by Pavel Gridnevskiy.

Beloretsk (Fig. S3) is a long distance south of the trajectory (Fig. S1). As such, the full lengthof the fireball is recorded. The car was in the process of stopping when the meteor appeared. The
scene has a mountain range seen far in the distance. The composite video image was lensdistortion corrected (no warp), rotated, and scaled to match the mountains in the star backgroundimage. Some stars are photographed below the meteor. The resulting alignment to foregroundfeatures is only approximate, but in reasonable agreement. Measurements were made every 1
second, starting at clock time 09:20:27 until 09:20:42, with peak brightness around 09:20:37.8.

Fig. S4. Alignment of star background image to a frame from video by Nikita Sonin in Snezhinsk.

6

In Snezhinsk, located far north of the trajectory, the foreground is also at a relatively far
distance and includes an apartment building and light fixtures (Fig. S4). The frame from a 25 fps
video was lens corrected, rotated and scaled, and the perspective changed to match theforeground features. Stars were photographed below the meteor track. The meteor peakbrightness was at about clock time 9:18:11.24. The fireball was recorded from 9:18:7.2-15.7.

Fig. S5. In Kamensk-Uralskiy, the meteor moved behind several lamp posts in this video by Aleksandr
Ivanov, with most foreground features in the far field.

In Kamensk-Uralskiy, Alexandr Ivanov obtained a spectacular video from a car stopped at a
traffic light (Fig. S5). The traffic light is visible to the right, which accurately marks the car's
position. The foreground features are all in the far field and include lantern poles behind which
the meteor moved. These features accurately mark elevation. The image was lens corrected andslightly warped to match the azimuth directions to the far-field lantern poles and park's trees.

Fig. S6. Video in Pervomayskiy was taken by Nikolay Ivanov inside the courtyard of a hotel. The meteor
appeared high right-of-center in the field, moving from bottom to top.

7

In Pervomayskiy, 25 fps video was rolling in a parked car with a scattering of ice crystals on
the front window (Fig. S6). The camera was facing east and the early part of the meteor track isrecorded. The meteor managed to avoid the ice crystals and is well tracked until the image
becomes large from blooming. Unfortunately, all foreground features are in the near field. Afterlens correction, rotation and scaling, the buildings and trees are in alignment. The foreground fir
trees are not matched, showing there is a small perspective problem. Useful data cover the video
clock times from 9:13:23.76 to 9:13:32.0, with peak brightness at 9:13:36.40.

Fig. S7. Korkino's central market place, in YouTube video posted by a user Nek Rosato. Meteor started in
the field and moved upwards.

In Korkino, a video recorded the onset and early part of the fireball, moving towards theobserver with a low angular velocity (Fig. S7). Peak brightness occurred at clock setting
9:43:05.80. The video camera is of the same type as Yemanzhelinsk (see below), which needed
twice the lens distortion correction of Chelyabinsk Savina Street. However, the near-field
perspective is unreliable. The corrected image was linearly scaled and rotated to align with thehouse, telephone poles and tree in the distance near the center of the image.
In Chebarkul, the meteor emerged from a bright glow, passed through the point of peakbrightness, then faded while leaving the field of view at the top (Fig. S8). The train of a second
fragment is visible at a slight angle. The video shows relatively modest lens distortion. The
image needed only a single Photoshop lens distortion correction and a perspective correction toprovide a match with foreground features, but trees further back were not matched correctly,
implying a small error in perspective. The corrected image was then shifted in azimuth to alignwith the furthest trees, which may not fully account for this error in perspective. Peak brightness
was at 09:16:44.23 clock time and the meteor tracked every 1/15th s from 09:16:45 - 48.17.
8Fig. S8. In Chebarkul, a rich near-field foreground is matched well, but trees further from the camera arenot. Right: Anna Kartashova shields the camera for one of the bright lights. YouTube video posted byuser Julia Rizhaya.

Fig. S9. Alignment of star background image to video taken in Yemanzhelinsk by Alexandr Zakharov.
The composite frame consists of the video frame taken at the site, plus a series of frames taken earlier
when the car passed under a gas pipeline. Peter Jenniskens shields camera from foreground light.

Under the meteor trajectory in Yemanzhelinsk, the final part of the fireball was filmed from amoving car. Towards the end of the recording, the meteor initially faded abruptly, returned
faintly for several frames before fading again and, finally, re-emerging in a single-frame terminal
flare. All foreground features are in the far field. Two locations of the car were calibrated, 34m
apart, one of which is shown in Fig. S9. As the direction in which the car was travelling did notchange much during the recording, the position of the meteor was transposed by aligning themeteor train in each measured frame. The position of the fireball in every 5th frame wasmeasured between 09:25.12 and 09:27.72 clock time. In addition, the car drove under a straightgas pipeline, creating a map of the lens distortion. Two times the normal lens correction (e.g.,
Fig. S2) straightened the meteor track and pipeline images transposed on the video frame (Fig.
9S9). The perspective was adjusted to align the far field. No warping was applied. Small
perspective errors are present near the edges.

Fig. S10. Alignment of foreground to star background image in Etkul. Video by Maxim Sevjukov.

In Etkul, the train appeared nearly overhead and was filmed by a hand-held camera (Fig.
S10). Based on the filmed arrival time of the shock wave (which occurred 44.7 s later), this video
frame was taken at 03:21:28 +/- 3s UT. The hand-held video did not have as wide angle a lens as
the dashboard-mounted cameras in cars. Scaling, rotation, and a small perspective change were
sufficient to reasonably align the image. Emphasis was given to aligning the distant towers.

Fig. S11. Alignment to a star background of one frame in this hand-held YouTube video posted by
Ekaterina Prokudina, taken at the Yemanzhelinsk bus station.

At the bus station in Yemanzhelinsk, the train was filmed by a hand-held camera. The
background building chimneys were used to align the direction of the image. Rotation and

10scaling were sufficient to achieve a reasonable alignment (Fig. S11). The filmed arrival of theshockwave (8.5s earlier) was used to time the image at 03:21:53.2 UT.
Shadows in Video Records
During peak brightness, the apparent fireball path was measured from shadows on the ground[42]. Of the 34 videos recorded on a single server in Chelyabinsk, fifteen show shadows crossing
features on the ground that can be used to identify its position at selected times (Table S3). Foursites in Chelyabinsk and one site in Chebarkul were analyzed. Those include the two videos
taken at the Revolution Square (#237) and the corner house at the Privokzalnaya Square (#30,
not shown), which were posted on the internet shortly after the event.

Fig. S12. Fireball (left) and Sun generated shadows (right) in video provided by Eduard Kalinin. (A)Fireball created shadows of lantern poles on the Revolution Square in Chelyabinsk (Site #237). (B)Corresponding calibration image of Sun shadow on 2013 May 24, at 3:27:11.3 UT; (C) Fireball shadow
on square in front of the administration building in Chebarkul (site #105). (D) Calibration image showing
same Sun generated light fixture shadows on 2013 May 24 at 3:57:23.2 UT. Arrow marks the shadow of
the light fixture seen in Fig. S12C.

11

Tape measure, rope, an inclinometer and a Craftsman laser distance measuring tool wereused to measure the height of obstacles and the length of shadows on the ground to determine theelevation of the meteor. The azimuthal directions are more uncertain and were determined byboth using a compass and from the orientation of maps presented in Google Earth.
Table S3. Summary of video-analyzed shadow sites.

Video #
30
105
160
237
301

Site
Chelyabinsk
Chebarkul
Chelyabinsk
Chelyabinsk
Chelyabinsk

Obstacle
Building
Light fixture
Sign
Lanternpole
Billboard

Lat.(N)55.143436
54.977272
55.172211
55.160144
55.167406

Long. (E)61.414183
60.370341
61.453558
61.402573
61.443214

Alt. (m)
232
338
242
229
235

Fig. S13. Viewing angles from shadow length and direction at four nearby locations in Chelyabinsk (left,
sites identified in Table S2) and one site (#105) in Chebarkul (+, right). Meteor moved from left to right.
Dashed lines show the viewing directions derived from the video records of the fireball itself.

Sun shadows at different times in the day were also used to calibrate the Chelyabinsk
Revolution Square and the Chebarkul administration building videos (Fig. S13). At Chelyabinsk,
the Sun shadow azimuth was directly matched to the azimuth direction of fireball shadows.
Elevation directions were derived from the sun shadow elevations after correcting for lensdistortion and perspective of the camera. Azimuth and elevation directions for the Revolution
Square and the Privokzalnaya Square (Fig. S13) are in good agreement with those determined by
Zuluaga et al. [42]. Systematic errors in azimuth were decreased from about ±2.5º to ±1º. The
12

measured directions agree well with those derived from the Chelaybinsk Savina Street video(dashed line Fig. S13).
In Chebarkul, the Sun shadow was only briefly in the field of view. Using the measured
height of the lamp fixture (14.5±0.3 m), the azimuth and elevation calculated for that point wastransposed to other positions using the grid pattern of tiles in the square (each 0.3018±0.0005 m
in width). The difference between the directions measured from the shadow and from the video
record is partially due to the different locations in Chebarkul (dashed line Fig. S13).
Trajectory and Orbit
Astrometric data were combined using the CAMS software package [43,44], from which the
trajectory data in Table S1 were calculated. In these calculations, the trajectory is assumed to belinear, with velocity decelerating with time (t) after reference time to described by two
deceleration parameters a1 and a2 [45]:V(t) = V∞ + a1 a2 exp (|a2|*(t-to)))Eq. S1

The method first calculates the intersection of the two planes through the meteor and two
stations, with best results for a large convergence angle, the angle between the planes (Q). After
that, individual lines of sight to the meteor in each video frame were used to optimize thetrajectory fit, including by taking into account the equal time between the measurements [44].
The trajectories are derived by allowing a variable time offset to optimize the fit, as a result of
which the trajectory is better defined as a function of altitude than as a function of time.
The result of the fit is sensitive to systematic errors. The measurements from Pervomayskiy
and Korkino do not agree: both stations are located almost under the trajectory, but one sees themeteor arrive from an initial azimuth of 100.9º (after matching to the furthest features in theframe), the other from 102.8º. Only by combining many different solutions was it made clear that
Pervomayskiy was slightly off, while the solution for Korkino was essentially correct.
Stations in Beloretsk, Snezhinsk and Kamensk-Uralskiy cover most of the meteor trajectoryfrom a distance, providing solution V∞ = 19.04 ± 0.09 km/s, a1 = 0.0013±0.0004 km and a2 =0.97±0.07 s-1. The apparent radiant is at R.A. = 328.39±0.12º, Dec. = 7.72±0.16º (here, the error
bar gives the random errors from astrometry only, not the systematic errors). Eq. S1 does notaccurately describe the deceleration. If we focus only on the >50 km part, Beloretsk, Kamensk-

13

Uralskiy, and Korkino, and assume no deceleration in this early part of the trajectory, then theradiant is at R.A. = 328.54±0.02º, Dec. = +7.17±0.02º, V∞ = 19.13±0.01 km/s.
Table S4A. Constant velocity solutions for different station combinations that contribute data above 25km altitude. Listed are apparent Right Ascension (R.A.) and Declination (Dec.) of the radiant andapparent entry speed (V∞), convergence angle (Q), as well as the altitude, latitude and longitude of the
beginning and end point. Solutions for small values of Q are unreliable (shaded).

Stations R.A.
(º)
PE-BE 328.15
KO-KU 327.82
PE-SN 328.06
PE-KU 328.08
KO-SN 327.77
KO-BE 327.98
SN-CS 328.06
BE-CS 328.10
KU-CS 327.84
PE-LE 328.31
KO-LE 328.65
SN-LE 329.72
CS-LE 328.82
BE-LE 328.50
KU-LE 330.08
PE-CS 330.31
PE-KO 328.49
KU-SN 331.30
BE-SN 328.48
KO-CS 332.48
BE-KU 330.00

Dec.
(º)
7.65
7.52
7.86
7.88
7.47
7.17
6.97
7.23
7.20
7.56
6.98
7.64
6.24
7.35
7.53
5.25
6.64
9.43
7.74
3.70
8.66

V∞
(km/s)
18.75
19.23
19.31
19.13
19.38
18.54
19.37
18.47
19.36
19.19
20.07
18.34
19.87
18.90
18.64
9.38
13.67
19.34
19.05
9.98
19.51

Q (º) H b(km)
82.5 90.7
69.5 89.8
87.0 92.4
81.7 90.8
74.8 91.0
70.2 88.8
68.3 54.3
63.7 84.6
62.9 65.7
51.6 93.5
39.3 93.1
35.6 52.2
32.2 59.6
31.0 86.8
30.2 63.5
18.8 57.0
12.2 66.8
5.3
66.5
4.6
87.5
6.5
57.3
0.8
85.4

Lat. b(º)
54.4867
54.4738
54.4808
54.4876
54.4675
54.4776
54.6806
54.4978
54.6106
54.4749
54.4565
54.731154.651154.512754.6656
54.635354.582154.621054.513954.6268
54.5103

Long. b(º)
64.2843
64.249964.331364.281864.285664.221362.637364.0323
63.1789
64.3733
64.3898
62.5771
62.8306
64.149763.1475
63.1737
63.5560
63.1894
64.162263.2926
64.0462

He
(km)
29.7
25.2
25.3
25.1
25.6
29.8
26.3
29.4
25.6
25.1
26.8
24.4
27.6
24.7
25.0
24.5
39.2
26.7
25.7
32.7
26.7

Lat. e(º)
54.843654.8596
54.8658
54.863654.860954.840954.851854.833654.8543
54.8752
54.862154.8789
54.8571
54.8804
54.872354.857954.7585
54.779754.8660
54.8167
54.7937

Long. e(º)
61.431161.2357
61.2266
61.238161.2308
61.4128
61.2367
61.3874
61.2288
61.129761.1163
61.1357
61.1169
61.1334
61.129661.234462.181761.2157
61.231261.5190
61.2167

Seven stations provide data on the early part of the trajectory above 25 km altitude, leading
up to and during the main disruption (Table S4A). Five video records are complemented byshadow measurements from Chelyabinsk and Chebarkul. Shadow measurements were sampled
every 0.5s, video observations every 1.0s. The trajectory solutions (assuming no deceleration) of
all combinations of two stations are listed in Table S4A. The divergence between solutions is ameasure of the systematic errors from mismatching the foreground in video and star backgroundimages. Solutions are ordered in sequence of convergence angle (Q), the angle between the twoplanes from the station to the meteor trajectory. Ignoring the Q < 20º geometries that have14

inaccurate results (shaded), the standard deviation is 0.68º in apparent Right Ascension (R.A.),
0.42º in Declination (Dec.), and 0.50 km/s in apparent entry speed (V∞). The standard errors indetermining the mean are 0.18º, 0.11º and 0.13 km/s, respectively. Combining datasets should
decrease these errors. Indeed, removing one of 7 stations (for a solution including deceleration)
results in a scatter with standard deviation 0.22º, 0.30º and 0.18 km/s, respectively, with standard
errors 0.08º, 0.11º and 0.07 km/s. Allowing deceleration in the solution still leads to constantvelocity fits being more likely. Hence, no significant deceleration was measured above 25 km
altitude. The mean values for radiant and speed at reference time 03:20:19.80 UT are:
R.A. (º)

Dec. (º)

V∞ (km/s)

a1 (km)V const., mean of 2-station 328.40±0.18 +7.35±0.10 19.10±0.13 -.all combined

328.64

+7.24

19.15

a2 (s-1)
-.-

-.-

-.-

mean of all -1 combined 328.62±0.08 +7.27±0.11 19.18±0.07 -.--.->29 km, no KO,PE

328.39±0.01 +7.46±0.02 19.16±0.01 -.--.->25 km, no KO, PE

328.36±0.01 +7.49±0.01 19.07±0.01 0.0

N/A

shadow only (CS,LE)

328.55

N/A

mean of all -1 combined

328.59±0.09 +7.26±0.10 19.24±0.05 ~5×10-4~0.54

all combined

328.62±0.09 +7.26±0.10 19.11±0.05 1×10-6

0.107

+6.08

19.67

0.0

Table S4B. Same as Table S4A. Deceleration allowed solutions for different station combinations that
contribute data below 25 km altitude
Stations
KU-YE
YE-BE
SN-YE
CY-YE
SN-CB
CB-KU
CB-BE
CB-YE
SN-CY
CY-BE
CY-KU
CB-CY
SN-KU
SN-BE
KU-BE

R.A.
(º)
327.87327.74327.29328.11328.88328.66328.50328.13340.54341.83339.35327.89317.29321.41293.04

Dec.
(º)
5.06
8.07
7.98
8.28
7.83
7.78
7.81
8.07
8.04
7.39
7.42
8.08
4.69
4.69
-9.4

V∞
(km/s)
10.53
14.51
9.53
19.90
11.32
10.88
11.13
25.12
15.11
15.96
17.32
18.63
10.63
9.65
47.59

a1
(km)
1e-6
3.906
9.5e-58.276
0.054
4.6e-42.1e-626.24
1.48e-3
0.726
4.08e-3
4.213
5.8e-4
0.0
105.4

a2
(/s)
3.269
0.513
2.049
0.405
1.127
1.598
2.309
0.180
2.336
1.030
2.631
0.588
0.012
0.0
0.137

t0 (s)
33.50
34.16
32.96
33.26
32.96
32.80
32.80
33.80
32.96
33.26
33.26
33.26
32.96
32.96
33.50

15

Q
(º)
79.3
78.9
74.2
73.2
59.9
54.7
55.1
46.0
32.6
27.8
27.4
27.3
5.2
4.8
0.5

Hb
(km)
23.4
24.2
23.4
24.5
24.3
23.6
24.5
30.7
22.9
20.9
26.1
23.4
25.4
24.3
32.9

Lat. b(º)
54.861754.9260
54.8672
54.8684
54.879954.8825
54.878154.847854.901854.9170
54.8605
54.882254.7983
54.835954.4297

Long. b(º)
61.1268
60.5918
61.1018
61.1374
61.1613
61.1448
61.1680
61.371061.2622
61.2323
61.2376
61.1641
61.1269
61.102961.0039

He
(km)
13.8
13.4
13.1
13.7
14.3
13.7
14.5
14.1
15.9
15.0
18.5
14.2
13.7
14.1
13.1

Lat. e(º)
54.931954.9260
54.923454.923954.932354.935254.931354.9355
54.9026
54.9135
54.8700
54.931354.924454.9243
54.8324

Long. e(º)
60.5705
60.5918
60.6047
60.6049
60.6395
60.631260.6561
60.5452
60.6453
60.6271
60.579460.7092
60.6173
60.6346
60.4470

Similar data for the lines of sight covering data below 25 km are listed in Table S4B. Meanvalues for reference time 03:20:32.96 UT:
R.A. (º)

Dec. (º)

V∞ (km/s) a1 (km)<25 km, mean of 2-station 328.12±0.17 +7.66±0.33 14.6± 1.8

a2 (/s)0.70±0.05 (0.8)<25 km, all comb., no CB 327.50±0.89 +8.97±0.89 14.46±1.38 0.35±0.28 0.81±0.05<25 km, all comb., no YE 327.60±0.10 +8.17±0.15 15.58±1.33 0.643±2.77 0.975±0.185<25 km, all combined

327.97

+8.05

12.58

0.027

1.31

The best-fit results to data in Tables S4A and S4B are shown in Fig. S14A. Above 25 km, thebest-fit trajectory is constant velocity fit, while below 25 km the best-fit curve has deceleration
with a1 = 0.35±0.03 for a2 = 1.0 (relative to time 03:20:32.96 UT).

Fig. S14A. Fireball trajectory as a function of altitude and time. Points are model fit solutions for stations
BE, KU, SN, LE and CS (> 25 km) and CY (< 25 km). Crosses are either begin or end points ofindividual 2-station solutions.

The initial speed is constrained by the individual data fits. In detail, the longitude at
03:20:32.65 UT from the trajectory fit above 25 km altitude is higher by about 0.055º than forthe solution below 25 km. In the same way, the elevation is about 0.7 km higher. To align the16

two solutions would demand an increase in the entry speed to at least 19.3 km/s. However, thesedifferences are also approximately the range of systematic uncertainties in the longitude andaltitude measurements.

Fig. S14B. Deceleration of the main fragment below 25 km altitude: dots with error bars are averages
over three 1/25 second frames from the perspective of the Chelyabinsk Savina Road video, while larger
dots are 1-second averages as seen from Beloretsk, Snezinsk, Kamensk-Uralskiy and Yemanzhelinsk. The
results are compared to falling 100 kg and 100,000 kg sphere models with density 3.3 g/cm3 (dashed).

Details of the velocity profile in this part of the trajectory are not captured by applying Eq.
S1. That would result in an abrupt drop of speed at 03:20:32.65 UT. The actual deceleration of
the main fragment, which continued to fragment and ablate, is shown in Fig. S14B and iscompared to that expected for a falling sphere of mass 100 kg or 100,000 kg (density 3.3 g/cm3).
A final mass up to 400 kg would also match the observed deceleration.
We adopt an apparent radiant at R.A. = 328.62±0.09º and Dec. = +7.26±0.10º. This trajectory
has an elevation of 18.3±0.2º and azimuth of 283.2±0.2º at the entry point at 97.1 km altitude
over 64.565ºE, 54.445ºN, where the meteoroid had a speed of 19.16±0.15 km/s. These values are
for reference date and time: February 15, 2013 at 03:20:19.8 UT. A summary of positions andaltitudes of key events is given in Table S1.
The apparent radiant corresponds to an Earth-gravity corrected geocentric radiant and speed:
R.A.g = 333.2±1.0º, Decl.g = +0.3±1.1º, Vg = 15.3±0.2 km/s at solar longitude 326.4269±0.0001º(J2000). The trajectory direction and location is in good agreement with that derived by17

Borovicka et al. [46], but we find an entry speed that is significantly higher (Table S5A). The
speed at the time of peak brightness is sensitive to the deceleration model assumed.
Table S5A. Overview of trajectory data for the Chelyabinsk asteroid (Equinox J2000).
Source
Entry
R.A.∞
Decl. ∞
Entry
Start Peak End of
speed V∞
(º)
(º)
Angle
Alt.
Alt.
disr. Alt.
(km/s)(º)(km) (km) (km)This work 19.16±0.15 328.62±0.09 +7.26±0.10 18.3±0.2 97.1
29.7 27.0±0.7
Y. & C.*
18.6**
328.9+7.3-.-.-.23.3
B. et al.
17.5±0.5
328.6±1.0+8.0±1.0
16.5
91.8
31.7 -.Z. & F.
16.5±3.1
333.8±2.7+12.4±2.7
18.1±1.7 ~39.6 -.22.7±2.4

Final
Alt.
(km)
13.6
15
14.9
-.-

Ref.

-.[47][46][42]*) based on U.S. Government satellite sensor data, no error bars. **) velocity at peak brightness.

Our value of entry speed is slightly higher than the 18.6 km/s apparent speed (uncertainty inthis value was not published) derived from satellite observations at the time of peak brightness[47], summarized in Table S5, perhaps suggesting that a small amount of deceleration occurredat the very end of the main disruption.
The radiant position and speed are significantly different, outside formal uncertainty
intervals, from earlier determinations of the entry trajectory [42, 46-47]. These results,
summarized in Table S5A, were derived from similar video observations, but using Google Earthto determine course astrometric directions to the fireball. The radiant position is in good
agreement with [47], but our entry speed is significantly higher. Both radiant and speed are
significantly different from [42]. These differences are important because the entry speed andentry angle affect the physical conditions of entry, and the direction (radiant) and magnitude ofthe entry speed determine the pre-atmospheric orbit of the meteoroid.
Preatmospheric Orbit
The pre-atmospheric orbit (Table S5B) was calculated from the observed apparent radiantand speed, by correcting for the Earth's rotation at the altitude of the meteor and applying
Schiaparelli's equation to estimate the gravitational attraction of Earth [44]. Error bars were
calculated from a Monte Carlo propagation of errors. Note that each orbital element is expressedin less significant digits than justified by the formal uncertainty in the solution, because therelative accuracy of the observed position of the meteoroid dictates a higher accuracy for any
given orbit solution that fits the entry speed and direction at that point. Because of this, the orbit
described by the elements as given in Table S5B passes by Earth. Expressed with additional
digits, the nominal orbit has perihelion distance q = 0.738893 AU, semi-major axis a = 1.763270

18

AU, eccentricity e = 0.580953, inclination i = 4.928787º, argument of perihelion ω =108.301927º and Node = 326.442018º (for Equinox J2000).

Table S5B. Overview of pre-atmospheric orbital data for the Chelyabinsk asteroid, with 1 standard
deviation uncertainties (Equinox J2000).
ω
Source
q
a
e
i
Node
Epoch
Ref.
(ΕΤ)
(º)
(AU)
(AU)
(º)
(º)
This work 0.739
1.763
0.581
4.93
108.3
326.4422
2013-02-15.139 -.±0.010±0.009±0.24±1.9±0.0014
Y. &C. *
0.750
1.764
0.57
4.2
109.90326.46-.[47]±-.±-.±-.±-.±-.B. et al.
0.768
1.55
0.50
3.6
109.7
326.410
2013-02-15.139 [47]±0.011
±0.02
±0.7
±1.8
±0.005
Z. & F.
0.828
1.73
0.51
3.45
120.6
326.702009-02-15
[42]
±0.03
±0.08
±2.02
±2.8
±0.79

Final Fragments
After the main disruption, at least two large fragments emerged in the video at Chelyabinsk,
causing two trains at a slight angle with respect to each other in the video from Chebarkul (Fig.
S8). In later photographs (Fig. S15), both trains are seen to have developed the double billowing
structure similar to the main train. The two trains are also seen in the train image by Marat
Ahmetvaleev at 3:20:43 UT, immediately following the fireball (Fig. S15A). Only one of the
trains (labeled "1" in Fig. S15) penetrated to low altitude.
The fragment that survived longest was discussed before, when examining the trajectory
below 25 km. It initially trailed the second piece, only to overtake it just when that fragment
faded at 18.0 km. The second fragment, as measured in Chebarkul and Chelyabinsk data (Fig.
S15B and C), arrived from a radiant R.A. = 326.5±0.2º, Decl. = 8.3±0.1º, with <V> = 13.05 km/s
assuming no deceleration. The fragment moved from 54.860±0.003ºN, 61.125±0.003ºE at 24.9
km to 54.899±0.001ºN, 60.806±0.001ºE at 18.0±0.1 km. The fading fragment moved slightly
south of the deeper penetrating fragment and may have dropped meteorites just south of the cityof Chebarkul.
The trajectory and speed are consistent with this fragment having created the hole in
Chebarkul lake. The trajectory was manually iterated to match the trajectory of Fig. S14A. It wasthen propagated with no wind, assuming a spherical mass of 100 kg. The precision of the impact
point (Long. = 60.2278ºE, Lat. = 54.9725ºN), about 5 km west of the Chebarkul Lake hole (Fig.
S53 below), is limited by the accuracy of the astrometric data below 25 km (Figs. 14A and B),
19ongoing ablation and fragmentation, and the unknown shape of the final mass, which limits theability to accurately determine mass or ballistic coefficient. Due to the low entry angle, a 200 kg
spherical mass would end up about 5.5 km further along the trajectory than a 100 kg mass. The
uncertainty ellipse along the propagated trajectory is about 20 km long. The uncertainty ellipse
perpendicular to the propagated trajectory is only about 1.6 km wide, with the Chebarkul Lakehole only 0.34 km south of the propagated trajectory. The expected wind drifts perpendicular to
the trajectory for a 100 or 200 kg mass of reasonable shape and density are less than 0.1 km (seeSect. 3.1, Table S15).

Fig. S15. Below 27 km, two fragments emerged from the main disruption. (A) Fragments are seen
separately in this photo by Marat Ahmetvaleev, labeled "1" and "2". Points mark the position of eachfragment in meteor video, projected on top of the star background images at (B) Chelyabinsk and (C)Chebarkul. (D) Each fragment's wake developed the double-train billows a short time later, documented
in this photo by Evgueny Tvorogov from Chelyabinsk (55.03632ºN, 61.08503ºE) at 3:21:52 UT.

Model of Meteoroid Orbital Dynamics(Contributed by: M. Granvik)
According to the Bottke et al. near-Earth object (NEO) model [33], Chelyabinsk has a 62 / 25 /11 / 2 / 0 % probability of originating from the ν6 secular resonance / the Intermediate Mars
Crosser region / the 3:1 mean-motion resonance / the Outer main Belt / Jupiter Family Comets.

20

These numbers cover the one-sigma orbital uncertainty given in Table S5B, and are an average
between adjacent bins in the semi-major axis, eccentricity, and inclination (a, e, i) space in orderto accommodate the estimated uncertainty.
Given the measured orbit in Table S5B, dynamical modeling using forward integrations
from realistic sources in the main asteroid belt was applied to calculate the time it takes for an
object to evolve to a Chelyabinsk-like or Itokawa-like orbit after entering the NEO region (Table
S6). Here, the 4:1 resonance is at ~2.06 AU, outside of the interval for Intermediate Mars
Crossers (a > 2.1 AU). Hence, the 4:1 resonance probabilities are included in the ν6 secularresonance source in the Bottke et al. model.
Table S6. Average time from first entering the NEO region until evolving to Chelyabinsk- or Itokawalike orbit in My (in brackets: minimum/median/maximum values) and number of particles in the modelthat arrive in such orbits (N).
Source region

Chelyabinsk

N

ItokawaNν6 secular resonance
4:1 mean motion reson.
3:1 mean motion reson.
Hungaria or Phocaea

10.63±0.95 (0.19/3.5/430)
3.19±0.73 (0.10/1.2/125)
8.87±1.85 (0.10/1.9/191)
25.2±2.5 (0.14/2.6/695)

861
194
184
658

27.6±6.6 (1.5/14.3/350)
12.2±3.7 (1.5/6.3/67)
13.0±2.5 (2.3/13.5/32)
62.8±8.2 (0.4/28.4/543)

64
19
14
101

If the evolution time is used as a proxy for the last possible collision in the main belt, then
one needs to add the ~1 My it takes to move from the post-collision orbit to the orbit bordering
the NEO region [48].
The test particles analyzed do not necessarily spend all the time in the NEO region but may
occasionally escape and then enter again. Particles escaping from the high-inclination Hungaria
and Phocaea regions have multiple escape routes, which more or less mix together. The
weighting for these regions is different, it typically being much more likely that the objects
originate in the low-inclination part of the inner main belt than the high inclination Hungaria andPhocaea regions.
Note that the tail of the evolution time is probably dominated by objects that escape the NEO
region and then enter again. Integrations were continued until a particle collided with the Sun ora planet, or escaped the (inner) Solar System. So, if the evolution time is used as a proxy for thelast possible collision in the main belt, then the tail is probably misleading as is also the average
evolution time. Hence, the median value listed in Table S6 (center value between brackets) is21

more reliable than the average.
The three fastest transport routes for Chelyabinsk from the low-inclination region are throughthe 4:1 or 3:1 mean motion resonances (~0.1 Myr), while the three fastest transport routes fromthe high-inclination region originate in the Hungaria group (0.14, 0.20 and 0.22 Myr).
The results (Table S6) suggest that (1) Chelyabinsk may be younger than Itokawa on purely
dynamical grounds and (2) both objects most likely originated in a low-inclination source region.
However, a higher-inclination (i > 7º) source region cannot be excluded.
1.2. Lightcurve and meteor modelLightcurve(Contributed by: P. Jenniskens)
The lightcurve of the meteor is the total radiated intensity of the fireball at optical wavelengths asa function of time or altitude. The lightcurves (Fig. S16) were derived from the fireballillumination of the ground and buildings in the video security cameras listed in Table S3.
Different video cameras are gain-controlled in different ways, as a result of which some record apeak in brightness as early as 03:20:31.2 UT, others as late as 03:20:32.2 UT. By comparing thebrightness of features in different cameras, it was possible to take these gain changes into
account. Gain changes were least apparent (or had slowest response) in video #30 (Table S3).
The camera saturates on directly illuminated features at peak brightness. However, the shape ofthe lightcurve during peak brightness was measured from the indirect illumination of shadowed
tiles in video #30 (Table S3).
Before and after peak brightness, the meteor brightness was measured from two videos takenin Yekaterinburg (early part, Fig. S17A) and Yemanzhelinsk (late part, Fig. S9). The sum pixel
intensity was corrected for saturation, using the method: F_corr = F_obs * exp (F_obs/F_scal)[49], where the scaling factor F_scal was determined by matching those parts of the lightcurvethat overlapped with data derived from the shadow videos.

22

Fig. S16. (A) Lightcurve of the fireball. Error bars approximate the uncertainty from absolute calibrationof the photometric data. (B) Lightcurve as a function of altitude.

Fig. S17. (A) Left: first detection of the meteor in unaccredited video that went viral on the internet, taken
near Yekaterinburg (Sverdlovsk Oblast - 56.7601N, 60.7639E). (B) Calibration image of wide-angle
dash-board mounted camera taken in Moscow by Andrey Shugarov (Institute of Astronomy RAS). Inset:
contrast enhanced area around the meteor and the moon.

Absolute calibration of the flux density was attempted by filming the near-full Moon in
Moscow using a Mediox DVR100 model camera on April 24th, 3 minutes before sunset undersimilar lighting conditions as the fireball 2.5 minutes after sunrise (Fig. S17B). The camera
adjusts the gain and offset depending on foreground features. The fraction of sky in the image
was about the same as that in the videos used to calibrate the lightcurve. The resolved image of23

the moon was detected. This corresponds to a -12.71 visual magnitude (98% of the moon's
visible disk was illuminated). The image's peak intensity level was 253, while the bright sky
background was 248 (0-255 full range).
The integrated luminosity between the calibration image and the first detection of the meteor(Fig. S17) corresponded to the meteor initially being 2.0 magnitude fainter than the moon. Thatmeans that the meteor, when it was first detected, was initially around -10.7 magnitude at a
distance from Yekaterinburg of 378 km. Hence, the initial absolute brightness (that is, as seenfrom a distance of 100 km) was -13.6±0.5 magnitudes.
This calibration puts the peak visible brightness of the fireball at -27.3±0.5 magnitude as seenfrom 100 km distance (Fig. S16). In Chelyabinsk, the apparent visible brightness was -28.8(±0.5) magnitude, brighter than the Sun at -26.0 magnitudes. Immediately under the track in
Korkino, it peaked at about -29.6 magnitude. Indeed, of the respondents in an internet survey(see below), 3 put the peak brightness of the fireball as bright as the full Moon, 39 fainter thanthe Sun, 105 as bright as the Sun, and 1,155 brighter than the Sun.
The lightcurve has an integrated brightness equal to 1.42 seconds of emission at peakbrightness. With an effective panchromatic passband width of 336 nm, this amounts to a total
radiated energy of 28-69 kT in this band.
Meteor Model(Contributed by: O. P. Popova)
The size of the Chelyabinsk meteoroid is large enough that its interaction with the atmosphereproceeds in the continuous flow regime. The Knudsen number (the ratio of the molecular mean
free path to a characteristic body size) decreases to 0.1 at an altitude of 90 km, where a shock
wave is formed around the meteoroid. Hydrodynamic models are able to describe the interactionof such large meteoroids with the atmosphere well - see review by Popova [50]. The ablation of
the meteoroid is mainly governed by the radiation from the shock compressed air and from theablation products [51,52]. Fragmentation adds more drastic effects than the relatively simple
effects of deceleration and ablation. Meteor models are typically varied by how they handle
fragmentation.
The hydrodynamical models that considered all effects, i.e., ablation, radiation and8fragmentation, are sparse and have so far been applied only to several large >10 kg objects (e.g.,24[51, 53-54]). They assume that the fragments are closely packed and behave as a liquid, but thesemodels cannot predict details of the fragmentation process, such as the simultaneous productionof dust and fragments. The behavior of smaller meteoroids is typically described by standard
equations based on the laws of conservation of mass, momentum, and kinetic energy [55-56].
The objective here is to fit in detail the observational data of the lightcurve (Fig. S16) and thedeceleration (Fig. S14), in order to reproduce some aspects of, or the total picture of, themeteoroid interaction with the atmosphere [55-57] or to derive meteoroid parameters such as theablation and shape-density coefficients [58,59].
The fragmentation may occur in different ways. One possibility is that a few large fragments
are formed, which initially interact through their shock waves and then continue their flight
independently and may be disrupted further (progressive fragmentation). This type of model
usually incorporates a strength scaling law, assuming that the strength of fragments increases
when the size decreases. Models differ by adopting different assumptions about the size
distribution of fragments formed. The possibility to describe the fate of individual fragments
makes it possible to describe the meteorite strewn field or the crater field.
A second approach is to assume that fragmentation occurs as a disruption into a cloud ofsmall fragments and vapor, which initially are united by a common shock wave [51]. Thisapproach is often applied to large bodies. These bodies (such as Tunguska, for example) may beessentially disrupted, but do not form separated fragments, all material continuing flight as asingle strengthless body [54]. If the time between fragmentations is shorter than the time forfragment separation, all the fragments move as a unit, and a swarm of fragments and vapor
penetrates deeper into the atmosphere, being deformed by the aerodynamical loading like a dropof liquid (called the "liquid-like" or “pancake” model). The smallest fragments fill the volume
between the larger pieces and quickly evaporate. But large fragments may escape the cloud andcontinue the flight as independent fragments. Both fragmentation scenarios are realized in real
events (much smaller than Tunguska), sometimes at different stages in the same meteor [56,60].
It is usually assumed that the destruction of a meteoric body begins at the moment when the
aerodynamic pressure in the vicinity of a stagnation point becomes equal to some constantdescribing the strength of meteoroid material. There are different approaches to the choice ofcharacteristic strength in the breakup criterion [51]. A compilation of data on stony meteorite
strength [51, 61-62] provides an average compressive strength of 217 ± 134 MPa, and an average25

tensile strength of 30 ± 17 MPa for gram-range samples recovered on the ground. In contrast,
observational data from 13 meteorite falls with accurate tracking data on atmospheric entry
resulted in estimated bulk strengths (meter-sized objects) in the range of 0.1 to 1 MPa on firstbreakup, while the maximal strength on breakup was no more than 1–10 MPa [62].
An initial meteoroid mass was assumed to be equal to M = 7 × 106 kg, the entry velocity = 19km/s, and the initial strength = 0.2 MPa. A heat transfer coefficient Ch~0.1 was adopted for the
initial body and for all fragments, which corresponds to an ablation parameter of 0.016 s2/km2,
similar to ~0.014 s2/km2 derived from other stony meteoroid falls [63]. The luminous efficiencies
used were those derived for the satellite detector passband from radiative hydrodynamic
numerical simulations [64,65]. The conversion factor to magnitudes was taken as 1.1 × 103 J/s
per zero magnitude [63], or 2.6 × 10-11 W/m2/nm for a panchromatic band of 336 nm width andstandard distance to the source of 100 km.
The adopted initial mass is lower than the estimated entry mass of 1.3 × 107 kg, but is chosen
within the factor of two uncertainty. An increase of initial mass by a factor of two would lead toan increase of the meteor brightness by about +0.5 magnitude prior to fragmentation, and about+1.5 magnitudes at the peak. Both the luminous efficiencies and the conversion factor to visual
magnitude are poorly known, which each can affect the brightness by up to a magnitude.
Our first attempts to model the lightcurve and deceleration was by using a progressive
fragmentation model with a range of possible size-frequency distributions of fragments (powerlaw, with two or a few surviving fragments) with a power law increase of strength withdecreasing size (not shown). This approach resulted in too many pieces and too much mass of
meteorites falling on the ground (about 300 tons in about 106 pieces), too bright radiation below
25 km altitude, and too small total irradiated energy (integral luminous efficiency ~6-8%).
The huge number of fragments formed at altitudes of 50-20 km during a short time suggeststhat the pure progressive fragmentation model fails because fragments cannot be considered
independent. The formation and deceleration of the cloud of small fragments and dust was
directly observed, emitting thermally at the final stages of evolution (Fig. S19, below). A hybrid
model between the progressive fragmentation model and the pancake model [60] may provide a
better representation. Unfortunately, the fraction of the initial mass that is converted into an
expanding cloud of fragments is poorly determined from the observations.

26

The masses of daughter fragments in subsequent fragmentations are chosen randomly inevery breakup. The fragment mass distribution of the surviving meteorites varied from one
model run to another, with the largest surviving fragment about 100-400 kg and the majority ofremaining fragments smaller than 10 kg.
This approach reproduces the main features of the light curve, but is based on a simplified
description of the observed fragmentation process. The solution is not unique. For example, byassuming that a larger number of clouds of small fragments and dust are formed also reproduces
the light curve, but requires even more free parameters.

Fig. S18A. Two model lightcurves fitted to the data (red and blue; black is observed data). These
represent two random realizations of fragmentation into three expanding clouds and a number of
separated fragments.

Figure S18A shows the result for two arbitrary solutions that produce a reasonable fit to theobserved lightcurve, albeit with small altitude discrepancies. For example, the narrow peak on
the blue curve corresponds to a disruption of large fragments that survived the main
fragmentation. There is a similar flare in the observed curve. The difference in peak intensity issimply caused by a different amount of mass involved in the breakup. Similarly, the higher
observed intensity at 50-40 km altitude means that a higher amount of decelerated material was
involved in the fragmentation at these altitudes.

27

Fig. S18B. As Fig. 18A, showing deceleration data from Fig. S14B. Speed of some fragments for the blue
scenario in Fig. S18A. Colors now refer to small debris and dust ("Clouds") formed prior to the 27-km
event (red), while "fragments" are the surviving fragments (blue).

These models also describe the observed deceleration (Fig. 18B). The deceleration curve
derived from the video records was nearly constant down to 27 km, followed by rapid
deceleration below 27 km, with the possibility of some deceleration just before the 27-km
altitude point (Sect. S1.1, Fig. S14B). The observed data is shown by black dots in Fig. S18B.
The velocity profiles for fragments in the blue model of Fig. 18A are shown. Colors now refer tosmall fragments and dust ("Clouds") formed prior to the 27-km event (red), while a few of thesurviving larger fragments are shown in blue. The final mass for the largest fragment is about
300 kg.
The number of fragments generated and the total amount of mass at any given altitude(including clouds of fragments and dust) are shown in Fig. S18C. The massive fragmentation at
32-29 km altitude created a rapid increase in the number of fragments. This corresponds to apeak in the energy loss at that altitude (Fig. S18E). Most of the mass and kinetic energy wasdeposited between 40 and 25 km altitude. The initial strength of the meteoroid was low, but thestrength progressively increased during the fragmentation process. The loading pressure needed
to continue the fragmentation process is shown in Fig. S18E-B.

28

Fig. S18C. As Fig. 18A. (A) Number of fragments versus altitude. (B) Total mass of all surviving
fragments as a function of altitude for the same two fragmentation model runs resulting into three
expanding clouds of debris and a number of separate fragments.

Fig. S18D. As Fig. 18A. (A) Energy loss as a function of altitude. (B) The strength of the fragments
as a function of altitude, for the same two model runs.

The number and size of fragments, their precise location in the strewn field, etc., changes
from one set of model assumptions to the next, but some aspects are well constrained. All need a29low fraction of fallen mass and a large energy/mass deposition above 20 km. The calculated
integral luminous efficiency is 18-20%. The evaporated mass is about 76% of the initial mass,
while 24% is converted into clouds of debris.
The cloud of fragments created in the 32-29 km breakup decelerated at altitudes of 27-23 km(observed: down to 26.2 km). This cloud of fragments resulted in the numerous small meteorites
found in the area centered on Deputatskoye (see Sect.3.1). Based on the number density ofrecovered small meteorites, the total surviving mass from that cloud of small fragments adds up
to about 3,000-5,000 kg (Sect.3.1).
The surviving fragments that stayed luminous below 25 km produced about 1,000 kg ofsurviving mass in the form of 20-2,000 individual meteorites in various model runs. These larger
fragments form the leading part of the meteorite strewn field. The extent of this part of thestrewn field varies from one run to another, but the largest fragment (mass 100-400 kg) is able toreach Chebarkul Lake for some model runs (see Sect. 3.1). The position of 3.4 kg meteorite(Sect. 3.1) is also in agreement with our modeling. Together with the surviving mass of smaller
meteorites, the total fallen mass is about 4,000-6,000 kg, i.e. 0.03-0.05% of the initial mass.
More typical surviving fractions for other ordinary chondrite falls are in the range 0.1-3 %.
Even lower fractions are known from fragile meteorites like the carbonaceous chondrite Tagish
Lake and the polymict ureilite Almahata Sitta [62].

1.3. Thermal Radiation and the Smoke Cloud(Contributed by: P. Jenniskens, O. P. Popova)
Thermal emission is responsible for yellow, orange, and red colors in the train just after thepassing of the fireball in the video from Kamensk-Uralskiy and in the still images of Fig. S5(also see Fig. 1 main manuscript), which were taken with short enough exposure (or far enoughfrom the trajectory) to not saturate the color bands.
This cloud of thermally emitting debris came to rest between altitudes of 29 and 26 km (Fig
S19). The color provides a record of the temperature: the red colors in Fig. S19B correspond to
700±100 K, about 5s after formation, if the smoke cloud is scattering sunlight with a color
temperature of 5,780K. Assuming the initial temperature was that of evaporation (a lower limit)
implies a cooling rate of ≥240 K/s. If the low elevation of the Sun at the time of the impact made30

the smoke cloud look a little redder than unfiltered sunlight, then that would slightly raise thetemperature estimate of the thermally emitting debris and decrease the cooling rate.

Fig. S19. Detail of the train's thermal emission. (A) Image posted by Mr. Dudarev on the Leprosorium
website (http://img.leprosorium.com/) taken about 5.0s after passage of the meteor. Sky background was
subtracted by applying a low-pass filter. (B) Image by Marat Ahmetvaleev, in an 0.6s exposure at 27 mm
f/14 using a Canon 5D at ISO 50 and Cokin graduated filter, taken about 6.0s after the meteor. Sky
subtracted in the same manner. Relative times derived from comparison with Kamensk-Uralskiy video.

The fireball smoke train exhibited most billowing between altitudes 80 and 27 km (Fig. S20).
During this early part of the trajectory, the dust cloud split in two because of buoyancy and thedevelopment of two cylindrical vortices [68]. Below 27 km, the train suddenly showed lessseparation and less billowing (Fig. S20C). At this time, two main fragments emerged, each ofwhich created a dust train that subsequently also split in two due to buoyancy (Fig. 15D).
The separation of the two cylindrical vortices shortly after formation (red lines in lower partof Fig. S21, showing a view from Yemanzhelinsk) is an indication of the amount of buoyancy ofthe hot air left in the meteor path, depending on air density and the amount of kinetic energy
deposited per kilometer along the trajectory. Most energy was deposited between 50 and 27 km,
in agreement with the general shape of the lightcurve (Fig. S16).
Above 40 km, the train showed a regular pattern of billows in an image taken from an aircraft(Fig. S22). A slight discoloration is visible between about 65 and 67 km altitude. This
discoloration was seen both in airborne and ground-based observations and corresponds to abrief displacement of the train in Northern direction (e.g., Fig. S22D). Wind models do show achange in wind direction at this altitude (Fig. S24 below).

31

Fig. S20. (A) Smoke train ~ 5 s after formation, still glowing from orange and red thermal emission.
Photo: Marat Ahmetvaleev. Approximate altitude markers in km. (B) Smoke train ~35 s after formation,
view from Chelyabinsk by Evgueny Tvorogov. Orange colors may now be from NO emission. (C) Smoketrain 46-73 s after formation, composite of several photographs by Tvorogov. (D) View ~1.5 min after
formation below the train in Yemanzhelinsk, showing the high billow and wide train separation during
the main flare. Photo: Victor I. Gubar.

Fig. S21. Train as seen from below in Yemanzhelinsk about 1.5 minutes after formation, before (top) andafter (bottom) an approximate correction for range, so vertical scale is the same for different altitudeparts. Photo: Victor I. Gubar.

32

Fig. S22. (A) Discoloration in the smoke train ~20s after formation, along with a less cropped photo forcontext (B), in an airborne photo taken by Sergey Valer'yanovich from the cockpit of flight Aeroflot 1639
from Omsk to Moscow. (C) Corresponding views from the ground in Chelyabinsk by Evgueny Tvorogov
at 9:21:45 UT and (D) a short time later at 9:25:29 UT. Arrow marks the discolored train feature.
Numbers refer to approximate altitudes in kilometer.

Our modeling (Sect. 1.2) suggests that this dust cloud contained a similar fraction (~ 24%) of
the original mass of the meteoroid than measured for other falls. These clouds are formed more
often at 60-30 km altitude, but data on particle size and mass fraction relative to that of theparent body are scarce [60]. Routine lidar observations detected such a dust cloud after the
fragmentation of a 600 - 1,900 t meteoroid over the Antarctic [66]. Satellite observations showedthat this meteoroid fragmented at 32 km altitude, with a second fragmentation at 25 km. The dust
cloud was recorded 7.5 hours later. The total mass of dust in that dust cloud was estimated at≥1,000 t (≥ 53% of the initial mass). Dust grain diameter and concentration were calculated as
0.4-0.98 µm and 2-6 106 particles per m-3, respectively. Similarly, the mass of the dust cloudformed after the disruption of the 4-m sized 2008 TC3 asteroid, observed by spaceborne midinfrared sensors, was about 25% of the initial asteroid mass, and 5% of that was fromrecondensed vapor [67].

33Prevailing Winds and Train Drift(Contributed by: L. G. Evers, J. Kuiper, V. Kharlamov, O.P. Popova, and P. Jenniskens)
In the northern hemisphere winter, the wind in the stratosphere is directed to the east. This wind,known as the circumpolar vortex, can reach strengths of over 150 m/s around the stratopause atan altitude of 50 km, which is the top of the stratosphere. Its strength gradually decreases
towards the lower stratosphere. In winter, the circumpolar directivity can be disturbed byplanetary waves that propagate from the troposphere into the stratosphere and interact with themean flow.

Fig. S23. Wind data from the ECMWF model at 06h UTC on February 15, 2013, in longitude and latitude
coordinates. Various slices of altitude in the stratosphere are shown, each with a separate velocity-coded
pattern of wind strength at particular atmospheric pressure in hectoPascal (corresponding altitude shownin parenthesis): 35.6 hPa (~22.2 km), 15.9 hPa (~27.0 km), 6.3 hPa (~32.7 km) and 0.3 hPa (~55.0 km).
The wind direction is given by the white vectors.

34

Atmospheric specifications of these winds are provided by the European Centre for MediumRange Weather Forecasts (ECMWF) every six hours (00:00, 06:00, 12:00 and 18:00 hour UTC)on a 0.5 by 0.5 degrees global spatial grid. The models consist of 91 levels with a decreasing
vertical resolution, i.e., as a function of altitude, from tens of meters in the troposphere to several
kilometers in the stratosphere. The top of the models lies in the mesosphere at a level of around
78 km. The non-forecast models are validated with actual measurements of atmosphericparameters like wind and temperature.

Fig. S24. The wind direction and strength from ECMWF specifications at 00h (black), 06:00 (red) and
12:00 UTC (blue) for 54.5ºN, 61.0ºE (solid lines) and 54.5ºN, 62.5ºE (dashed lines). The inset in the windstrength frame zooms into the lower stratosphere and troposphere.

Fig. S23 shows the wind strength and direction over the area of interest for 06:00 UTC for
several levels in the stratosphere. A well-developed circumpolar vortex is present over the area,
which is predominantly directed from the west to the east. At lower levels the vortex points
towards a more southeastern direction. The strength varies from a couple of meters per second in35

the lower stratosphere to over 100 m/s around the stratopause. The lateral variations in the windstrength increase with altitude from 6.1 m/s at 35.6 hPa to 14.6 m/s at 0.28 hPa. The windstrength is lowest at 15.9 hPa with a value of 4.4 m/s.
In order to assess the variation in the wind as a function of time, the 00:00, 06:00 and 12:00
UTC model outputs are plotted in Fig. S24. The profiles are valid for 54.5ºN, 61.0ºE near
Deputatskiy (point t1 in Fig. S26 below) and for 54.5ºN, 62.5ºE, close to point t6 in Fig. S26.
Data from local meteorological stations measured the wind at ground-level to be of about 1-3
m/s in agreement with the model. The ECMWF wind profile below 30 km is also in good
agreement with that derived from atmospheric sounding at the Verkhneye Dubrovo station(56.73ºN, 61.06ºE), the nearest station to Chelyabinsk (Fig. S25).
During the day, there is an increase in the wind velocity in the (upper) stratosphere, while thewind direction varies around an average value of 270 degrees, i.e., a wind to the east. In thelower stratosphere and troposphere, there seems to be a larger variation in the wind direction,
while the strength is much less variable. The wind strength in the lower stratosphere is about 10
m/s (see the inset of Fig. S24). The average direction is towards the southeast. Theseobservations are consistent for both location t1 and t6. However, it should be noted in the abovethat the resolution decreases with altitude, which does not allow fine scale structure to beresolved in the upper stratosphere in as much detail as in the lower stratosphere and troposphere.

Fig. S25. Wind profile from atmospheric sounding at the Verkhneye Dubrovo station (56.73ºN, 61.06ºE),
the nearest station to Chelyabinsk, at 0:00 UT (red line) and 12:00 UT (blue line) on February 15, 2013.

36

Based on the above analysis, the higher part of the smoke train is expected to move to theeast as a function of time (opposite to the direction of the meteor and slightly to the north), while
the lower part, i.e., lower than 27 km, should exhibit a displacement to the southeast. Due to thestronger winds in the upper atmosphere, the higher part is expected to disperse faster than thelower part. Unresolved fine scale structure in the stratosphere, for example due to gravity wave
activity, may lead to additional wind shear, which can extend over several kilometers in altitude.

Fig. S26. Chelyabinsk airport radar detection of the smoke train shortly after the fireball (black band
below yellow line, the video-derived fireball trajectory). Points labeled t1 through t6 are discussed in thetext.

The dust cloud was detected by the airport radar in Chelyabinsk, which scans around at a rateof 12 rotations per minute. A slightly blurred photograph of the radar screen was taken a shorttime (time unknown) after the event (Fig. S26). The map shows 10-km spaced concentric circles
and 10º radial lines, as well as a number of identified locations. Those locations were aligned
using Google Earth and reflections identified as possibly from the train are highlighted in black.
The approximate altitudes corresponding to the six points in Fig. S26 correspond to t1 ~ 22.7km, t2 ~ 27.3 km, t3 ~ 30.3 km, t4 ~ 36.7, t5 ~ 46.6 and t6 ~ 52.8 km altitude, assuming only
southward drift, and correspondingly lower altitudes if the drift was also towards the east. The
wind direction-change around 29 km is responsible for the break in the train in Fig. S26. Mildwinds between 22 and 27 came from about 310º. The train is indeed located slightly south of thefireball trajectory. Above 30 km, the curvature in the train is that expected from wind strengthchanges as a function of altitude (Fig. S24). The much stronger winds between 30 and 58 km
were from 270º, and the train would be expected to have moved slightly north of the fireball37path, rather than slightly south. Hence, local winds around 03:20 UT appear to have been slightly
more north of due east.
Fig. S27 shows the lower part of the train at 24-18 km altitude as observed from
Yemanzhelinsk 81±1 seconds after peak brightness of the fireball, and from Etkul 56±3 s after
the fireball. Both images were calibrated against background stars (Fig. S10-S11). The train at
18.5 km altitude was calculated to have drifted south perpendicular to the line of sight at a rate of
5.5±0.1 m/s in Yemanzhelinsk and 4.2±0.2 m/s in Etkul. The ECMWF model (Fig. S24) and theatmospheric sounding measurements at Verkhneye Dubrovo station (Fig. S25) have a southerncomponent to the wind speed perpendicular to the line of sight of ~8 m/s.

Fig. S27. Train drift relative to the best-fit fireball trajectory (solid line), as filmed in Yemanzhelinsk andEtkul. Black dots are modeled directions, open circles are the actual measurement points. At both sites
below the track, the train had drifted in southern direction by the time these images were taken.

381.4. Infrasound Data
(Contributed by: Y. S. Rybnov, V. A. Kharlamov, O. P. Popova, A. Solovyov, Y. S. Rusakov,
V. V. Shuvalov)
Infrasound waves are low-frequency (< 20 Hz) acoustic waves above the 10-3 Hz Brunt-Vaisalafrequency of the atmosphere. They attenuate slowly and can travel on global scales. The
Chelyabinsk meteoroid generated infrasound waves that were recorded by 11 Comprehensive
Nuclear-Test-Ban Treaty Organization stations (CTBTO), as well as other stations all over the
globe [69].

Fig. S28. The infrasound signals from the Chelyabinsk event recorded at IDG, Moscow. Shown signals
are filtered in the range 0.01 - 1 Hz.

In this section, signals are discussed that were obtained in four locations nearest to theimpact: (1) at a ~1,500 km distance in Moscow at the Institute for Dynamics of Geospheres(IDG), shown in Fig. S28; (2) at a ~1,500 km distance in Mikhnevo at the Institute for Dynamics
of Geospheres' Geophysical Observatory; (3) at a ~1,520 km distance in Obninsk at the Researchand Production Association "Typhoon" (Fig. S29), and (4) at a ~1,600 km distance in Tomsk at
the Tomsk State University (Fig. S29). In addition, another relatively close range infrasoundrecord was obtained by one of the CTBTO station in Kazakhstan is discussed (IS31,
Aktyubinsk), located ~520 km from the impact (Fig. S29). Microbarometers with a frequency
range 0.001-10 Hz were used at IDG and Mikhnevo, while those in Obninsk and Tomsk weresensitive over the range 0.003-10 Hz. Aktyubinsk (IS31) is equipped with absolute pressure
microbarometers (MB2000, France), sensitive from 0.001 to 4 Hz.

39

The propagation of infrasound waves, and their interpretation as a source of information
about the kinetic energy of the Chelyabinsk impact, is sensitive to local atmospheric conditions.
To verify that these signals originated from the Chelyabinsk impact, the bearing angles were
determined by Progressive Multi-Channel Correlation (PMCC; [70]) and by the correlation
function method [71] to a precision of about ±0.50, which corresponds to about ± 13 km in
Chelyabinsk area. At the first approximation winds were ignored. All bearing angles passed
within 15 km from Karataban, about 20 km east from Yemanzhelinsk. The infrasound signal
arrived in Tomsk earlier than in Moscow/Obninsk, suggesting western winds of about 23.5 m/s
on average in the stratospheric waveguide where the signal was propagating.
The influence of wind on the propagation was calculated based on the wind data fromweather stations along the trajectory of propagation (Fig. S25). Based on the available data, themeasured average wind speed was 23.3 m/s, in agreement with the estimate above. By taking
these wind speeds into account, the source position shifts about 30 km westward and is now
centered between Korkino and Yemanzhelinsk, close to the position of peak brightness based on
the video data (Sect.1.1).
At distances larger than a few hundred kilometers, the infrasound waves from meteoroid
entries are very similar to those from chemical explosions with the same kinetic energy released[72]. Estimating the source energy for infrasound sources generally relies on empirical scaling
relations derived from known sources. These relations use either the period at the maximum
amplitude of the signal or the peak-to-peak amplitude [73-76].
Ens et al. [8] have examined a data set consisting of 71 bolides detected by satellite sensors,which provided energy and location estimates, with simultaneous measurements of the same
events by infrasound detectors. The energy of these bolides was about 0.02–20 kt TNT
equivalent yield. Based on a mean amplitude-yield relationship, the predicted amplitudes for a 1
kt event varied by nearly two orders of magnitude at a distance of 1,000 km. The Chelyabinsk
event would result in an extremely low energy of less than a few kilotons, based on theamplitude of 2 Pa at 1,500 km.
Infrasound signals from 30 Soviet air nuclear explosions at altitude not exceeding 4,000 m,
with energy yields from 10 to 2,400 kt TNT, were recorded at distances from 500 to 3,000 km[77]. The amplitude of the infrasound signal varied by a factor of 4-8, depending on the windvelocity and direction at stratospheric heights (40–60 km), the direction to the source, and the40

weather conditions at the registration point. Again, the amplitude-yield relations are not very
precise at these long ranges.

Fig. S29. The infrasound signals from Chelyabinsk event recorded at Obninsk, Tomsk, and Aktyubinsk(IS31). Shown signals are filtered in the range 0.01 - 1 Hz.

The period at maximum amplitude is generally more insensitive to propagation effects than
the amplitude of the signal. From the period-yield relation derived by Ens et al. [8], a yield of41

~470 kt TNT was previously reported for the periods observed at international locations of the
CTBTO network [78]. To better understand the uncertainty in this number, we analyzed the datafrom Russia and Kazakhstan.
Based on the Stevens et al. [77] infrasound data, the frequency at maximal amplitude fmchanged only a few percent when the distance was doubled. The dependence of yield (E) on thefrequency fm can be approximated as follows:,
where E is the energy yield anddistribution of

Eq. S2is the proportionality coefficient. The probability

as well as their dependency on the propagation direction are shown in Fig.

S30. Application of the χ2 criterion shows that these distributions are log-normal to good
approximation, with mean values
direction, andfor the signal propagating in an east-west

for the propagation in the north-south direction.

Fig. S30. The probability distribution of coefficientsin the direction east-west (a), and north-south(b) derived from experimental data.

The frequency spectra of the Chelyabinsk event are shown in Fig. S31. The characteristicfrequencies (at maximum amplitude) are about fm ~0.039 Hz for Tomsk, 0.032 Hz for Obninsk,
0.0285 for Aktyubinsk and 0.0326 Hz for Moscow. The early peak at even lower frequency in
the Moscow spectra (~0.014 Hz) may be due to turbulence, but that remains uncertain. Fromthese frequencies, the yield was calculated.

42

Energy estimates, summarized in Fig. S32, vary by about a factor of 2.5. The mean is433±127 kt TNT. If the lowest frequency value would be taken as representative, the estimatedenergy would increase a few times, which would put the Chelyabinsk event into the Mt energy
range.

Fig. S31. Spectra of infrasound signals (Pressure in Pa versus frequency in Hz) at different locations(Tomsk, Obninsk, IDG) and a wavelet representation of the spectrum recorded at the Mikhnevo IDG
station shown in 3D color. Spectral power (in arbitrary units) is plotted as a function of time andfrequency period.

The scatter is caused by the influence of stratospheric winds on signal propagation. The windvelocity at stratospheric heights may exceed 50 m/s. It is possible to take the effects of winds
into account by considering how stratospheric winds vary seasonably [74-76, 79-80]. Based on43the Stevens et al. [77] dataset, the frequency at maximum amplitude varies as a function of the
distance from the energy source:,

Eq. S3where E is the energy yield in kt TNT, fm is the characteristic frequency and R is the distancefrom the source in km, d is the azimuth and season correction factor (see below). Coefficients inthe equation are as follows: a~0.65, b~2.3 and c~0.49.
The factor d may be expressed as d = Ks*Ka, where Ks is the seasonal coefficient and Ka is
the azimuth coefficient. Ks takes into account the seasonal variation of wind velocity, and Ka
incorporates the azimuth from the source to the registration point. The values of thesecoefficients, based on the Stevens et al. [77] data, are given in Fig. S33.

Fig. S32. Energy estimated (A) based on Eq. S2 (left), showing a range of solutions, and (B)based on Eq. S3 (right), taking stratospheric winds into account.

Fig. S33. Azimuth correction coefficient Ka (left) and seasonal correction coefficient Ks.

44

The yield estimates based on Eq. S3 are shown in Fig. S32. The average energy estimate
now is 432±60 kt TNT. The results from one station to the next are now in better agreement.
This is not the full story. Eqs. S2 and S3 are obtained based on analysis of infrasound records
from nuclear explosions at altitudes below 4 km. The corresponding yield of a chemical
explosion, for example, is two times smaller due to a different partitioning of energy going into
the blast wave [81-84]. The height of the burst may increase the effective energy yield as thepartitioning of the energy changes with altitude [84-85]. In addition, free air explosions tend tohave about a two times higher yield due to the absence of a surface reflection [86]. At thealtitude of about 30 km, the correction factor is thought to be about 1.33±0.30 [84-85]. There isno calibration data, however, for such high altitudes and such high energies. The influence of theheight of the burst on the infrasound signal at long distances is unclear [79]. With these caveats,
the most probable kinetic energy of the Chelyabinsk meteoroid impact is 570±150 kt TNT.
1.5. Witness Reports: Smells(Contributed by: S. Korotkiy, I. Serdyuk, A. Kartashova, S. Khaibrakhmanov)In the immediate aftermath of the fireball, various smells were reported in a wide area aroundthe fireball trajectory. Most distinct smells were reported while under the trajectory and starting
about one hour after the event.
Data on smells can only be collected by interviewing witnesses. Two approaches were taken
to collect a variety of data from witness interviews, results of which are summarized in Table 7A
and 7B. In this section, data on smells are discussed.
First, a total of 1,674 witness accounts were collected via a questionnaire on the internet, agreat example of crowd sourcing. Unfortunately, the responses are mostly from highly populatedareas centered on Chelyabinsk, the Miass / Chebarkul area, and the highway M36 corridor (Fig.
S34). Questions asked included requesting information about the eye witness location, sounds
heard (yes, no, or observer was inside at the time of the event and therefore could not hearsounds from the meteor), temperature effects (observer became hot, felt some heat, did not feel
heat, was inside, provide own description), smells (smell of burning, no smell, own descriptionof smell), ashes (yes ashes, no ashes, did not notice), blast wave arrival (time difference
estimated, yes, did not hear, was inside), and whether there were any injuries (Table S7B).

45

Fig. S34A. Eye witness reports on smells collected by internet query. Red = "burning smell", blue "nosmell", yellow points are "other", mostly also reporting smells of various kind. The black line is thefireball trajectory.

Secondly, to cover the smaller villages in the area as well, some 50 villages and towns werevisited between 3 and 5 weeks after the event, during which time about 150 locals werequestioned (Table S7A). These offer natural sampling points for information, because thepopulation is concentrated in villages and small towns, with no houses in between. In most cases,
several people in the each village were questioned (the number given in the first column of Table
7A), often starting from those operating the local grocery stores and including random observers
encountered on the street, until reports of damage were confirmed. In addition, several telephoneinterviews were made to cover further outlaying villages (labeled "*" in Table 7A) and data fromofficial reports were collected for a few major population centers (labeled "**" in Table 7A).

46

Fig. 34B. As Fig. 34A, wider area with reports of smells (large red dots) from eye witness interviews.
The strongest smells were from locations under the trajectory.

The witnesses were asked whether the fireball was seen (was the light blinding, did they havepain in their eyes, was heat felt, did sunburn occur?), how the impact of the shockwave wasexperienced (level of shaking, was dust generated?), whether damages or injuries occurred(structural damage, flying glass?), whether unusual scents were smelled, and whether meteorites
were found locally.

47

Field survey reports of smells were concentrated in the area surrounding the fireballtrajectory, with scents starting about an hour after the event (Fig. S34B). Fourteen villages where
scents were reported are marked using red labels on the map of Fig. S34. The eastern edge of thearea coincides with the eastern edge of the glass damaged area (Fig. 3). Similarly,
Arkhangel’skoe is the most western village where smells were reported, which is situated near
the western edge of the glass damaged area.
Nearly all respondents reported similar scents, described either as a sulfur smell, a burning
smell, or a smell similar to that of gunpowder. After an initial strong burst, the scents continued
for a few hours. These smells may have originated from the decomposition of troilite (FeS),
which is one of the main component of this meteorite. Alternatively, some burning scents may
have been caused locally when the shockwave dispersed soot from flues and stoves.
Respondents in Emanzhelinka, immediately under the fireball trajectory, also reported anozone smell, similar to that smelled after a thunderstorm. Ozone may have been produced in theimmediate surroundings of the fireball from UVB radiation of the meteor with λ= 200-300 nm
wavelengths. This fact supports reports about the prevalence of sunburns, also caused by UV
radiation.
Table S7A. Summary of eye witness reports ordered per village/city (-.- = no data; ">" = followed by). #is number of persons interviewed. D is the ground projected distance from the village center to the point
below peak brightness at Lat. = 54.845ºN, Long. = 61.412ºE.
#

Location

Heat

Smell

Sound

Shaking

Dust

Aleksandrovka
Arkhangel'skoe

D
(km)
10
30

4
3

-.-.-

no
sulfur

yes
faint

-.-.-

-.no

1
4

Bashakul’
Baturinskiy

95
8

-.yes

-.strong

noise
yes

-.-.-

-.no

3

Belonosovo

4

yes

-.-

-.-

-.-

2
3
1*
1*
5
1
6

Beloretsk
Belousovo
Beloyarskoye
Bereznyaki
Brodokalmak
ButakiChebarkul

219
35
79
15
92
27
68

no
no
-.-.yes
-.-.-

no
yes
-.-.no-.nono-.faint
yes
faint
-.-.-

30

Chelyabinsk
center

34

yes

yes

no
3 plops-.-.-.-.strong+
few faint
yes

ashe
s
no
-.-.-.-.-.-.-

yes

yes

48

Glass
damageyessome old
windows
nosevere,house
crackedyes

Aggrieved
person-.headaches

Injuriesnono-.headaches

no
-.-

-.-

no

no
one
no
-.somesomenono-.-.-.-.-.nonono-.-.no
no
no

some,
roof

yes

yes

38

-.-

-.-

yes

yes

-.-

collapse
some

-.-

yes

35

-.-

-.-

yes

yes

-.-

severe

-.-

-.-

96
18
57

-.yes
-.-

-.-.-.-

-.yes
-.-

-.yes
yes

-.-.-.-

no
some
no

-.no
-.-

-.no
no

2
8

Chelyabinsk
State
University
Chelyabinsk
South Ural
State
University
ChumlyakDeputatskiy
Dolgoderevenskoe
Emanzhelinka
Etkul

9
11

heat feltno-.2 strong
>few
faint

-.a few
minutes-.sootseveresevere

-.-.-

yes
yes

3

Kalachevo

13

yes

ozone
sufur
and
burnedwire
burnedwire

3 plops-.--.-

2 mencuts

yes

5Karataban

26

yes

no

-.-

-.-

-.-

no

2

Kazbaevo

39

-.-

no

yes

no

no

no

1*
3

KoelgaKolobanovo

39
40

-.-.-

-.no

-.no

Some
no

-.no

-.no

4
3

Kopeysk
Korkino

38
6

yes
yes

yes
-.-

-.-.-

severe
yes

-.yes

yes
yes

6
1
4
1
3
1
5

Kunashak
Lebedevka
LesnoyMarkovo
Miasskoye
Muslyumovo
Nikolaevka

96
39
55
49
58
85
36

yes
sunburn,peelingno-.-.-.-.-.no-.strong+
few faint
-.yes

sharp
shock
long
shaking-.nosever,
house
crackedonly old
windowsnofaint-.-.faint-.-.-.--.-.-.-.-.-.-.-

no
no
some
no
significant
someno-.-.-.-.-.-.-.-

no
no
no
no
yes
no
no

4

Novobalandino

35

yes

-.-

no
-.no
-.-.-.1> few
faint
faint

-.-

hospital

Novotroitskiy
Nugumanova
Pervomayskiy
Petrovskoe

25
76
15
48

-.-.yesnono-.-.no-.-.-.-.-

someschool
yes
some

1
4
2
2
1
2
1
3

Pogudino
Poletaevo
Polevskoy
Potapovo
Preobrazhenka
PriozerniyRozhdestvenka
Russkaya
Techa
Sakkulovo
Sary

40
28
196
22
50
9
49
110

no
yes
no
-.-.-.no
yes

-.yes
no
no
-.-.no-.--.-.no-.-.-.-.-.--.-.no-.-.-.-.-.-

no
some
no
some
no
yes
some
no

-.-.no-.no-.-.-.-

no
no
no
no
no
-.no
no

71
7

-.-.-

-.-.-

3 plops
-.yes
1>few
faint
yes
3 plopsnono-.-.1 strong
1 strong >thundr-.-.-headaches,eyes hurt-.-.-.-.-

yes

2
**
2
3

ashe
s
-.-.-.-.-

-.-.-

-.-.-

no
some

-.-.-

no
no

20

20

1*
7
2

2
1

no
no
yes
no
no
-.burning

49

no
no
-.no

2
2
**
1

SmolinoSultaevo
Surakovo
Taendy

24
70
73
24

-.-.-.yes-.-.-.sulfur
gunpowder
no
no
-.no
-.-.no-.3 crashes-.1 strong>
3-4 faint

-.yes
-.yes

-.-.-.-.-

schoolnoschoolyes-.-.-.-.-

no
no
no
no

5
5
**
2
3
2
5

42
55
86
142
45
53
242

-.sunburn-.no-.-.no1*
15
6Timiryazevskiy
Travniki
Troitsk
UchalyUvel'skiy
Varlamovo
Verkhnyaya
PyshmaYaroslavka
Yekaterinburg
Yemanzhelinsk

yes
1>5 faint
-.no
-.yes
no

5 min
no
-.no
yes
yes
no

no
no
-.no
-.-.no

no
no
some
no
some
no
no

no
no
-.no
-.-.no

no
no
no
no
yes
-.no

50
226
11

-.no
sunburn

-.no
yes

-.no
yes

yes
yes

no
no
severe,statuecrackedyessevere

-.no
yes

yes
yes

-.-.-

-.-.-

yes

no

-.no
soot,
ashe
s
-.ashesno-.noheadaches

-.yes

-.no
sulfur,bitter
taste
-.yes

**
3

Yuzhnouralsk
Zaural'skiy

45
13

5

Zvyagino

44

no

no

no

1 strong> 5 min.
few faint* based on telephone interviews; ** reported by authorities.

Table S7B. As Table S7A, giving summary of eye witness reports collected by internet query, ordered
per village/city (-.- = no data; ">" = followed by).
#Location

D
(km)

Heat

Smell

Sound

Shaking

Dust

DamageAggrieved
personMeteorites

1
2
2
12
1
1
1
1
1
1
2
1
1

Akbasheva
Aleksandrovka
ArgayashAsbestBarachinskiy
Baturinskiy
Belonosovo
Beloretsk
BelozeryBishkil'Bobrovka
Bogdanivich
Bolshoye
Balandino
Bolshoye
Kharlushi
Borisovka
Celinnoe
Chebarkul

62
10
80
240
385
8
4
219
83
44
92
219
58

-.-.yes
no
no
yes
yes
no
yes
no
yes
no
-.-

no
no
no
no
no
yes
-.no
no
no
yes
no
yes

no
yes
no
no
no
yes
-.no
no
yes
yes
no
-.-

-.-.-.-.-.-.-.-.-.-.-.-.-.-

no
-.no
no
no
no
yes
no
no
no
no
no
-.-

-.yes
-.-.-.-.yesno-.-.-.-.-.--.-.-.no
no
yes
-.no
-.no
yes
no
-.-

-.yes
-.-.-.yes
yesno-.-.-.-.-.-

50

yes

no

no

-.-

no

-.-

-.-

-.-

15
151
71

no
no
no

no
yes
no

yes
no
no

-.-.-.-

nono-.--.-.nononono-.-.yes

1
2
1
6

50

1301
1
1
2
2
4
3
1
1
4
3
2
1
1
2
1
2
3
1
1
32
1
20
2
1
3
1
1
12
1
3
6
1
2
1
1
2
1
5
1
1
1
1
1

Chelyabinsk
Cheremushki
Cherkasovo
Churilovo
Dolgoderevenskoe
Emanzhelinka
Etkul
Il'inoIshalino
KamenskUral'skiy
Kanashevo
Kasargi
Kashino
Kasli
KatayskKazantsevo
Khomutinino
Klenovka
Kluchevka
Kluchi
Kopeysk
Korablevo
KorkinoKostanay
Krasnoe Pole
Krasnogorskiy
Krasnoufimsk
Krasny Partizan
Kremenkul'
Krugloe Lake
KurganKurochkino Lake
Kusa
Lazurny
Lebedevka
LesnoyLubimovo/
Uksyankoe
Magnitny
Magnitogorsk
Malaya Sosnovka
Malysheva
Medvedevo
Medvedskoe
Metlino

37
56
52
43
57
9
11
54
66
175

yes
no
yes
yes
-.yes
yes
no
no
no

yes
no
yes
yes
no
yes
yes
no
no
no

no
yes
yes
no
no
no
no
no
no
no

yes
-.-.-.no-.yes-.-.-.-

no
no
yes
no
no
no
yes
no
no
no

-.-.-.-.noyesyes-.-.-.-

yes-.yes - ears
no
-.no
-.no
yes
no

-.-.-.-.-.yes-.-.-.-.-

56
57
192
120
176
48
35
17
57
48
38
21
6
233
43
30
295
287
40
44
261
22
134
60
39
55
161

no
yes
no
no
yes
yes
yes
-.yes
-.yes
no
yes
yes
yes
yes
no
no
yes
yes
no
yes
yes
no
-.-.no

no
no
no
no
yes
yes
yes
no
no
yes
yes
no
yes
no
no
yes
no
no
yes
no
no
yes
yes
no
no
yes
no

no
yes
no
no
no
yes
no
yes
yes
yes
yes
no
yes
no
no
no
no
no
yes
yes
no
no
no
yes
-.no
no

-.yes
-.-.-.-.-.-.-.-.yes-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

no
no
no
no
no
no
no
no
no
yes
no
no
no
no
no
no
no
no
no
no
no
no
no
no
-.-.no-.-.-.-.-.-.-.-.-.-.yes-.yes-.-.-.-.-.-.-.-.-.-.-.-.yes
-.-

no
-.no
no
no
-.-.-.no-.yes - eyes, ears
no
yes
no
no
-.-.noyes - eyes
-.no
no
no
no
-.-.no-.-.-.-.-.-.-.-.-.-.yes-.yes-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

220
220
25
36
43
110
105

no
no
-.no
-.no
no

no
no
yes
no
no
no
no

no
no
yes
no
yes
no
no

-.-.-.-.-.-.-.-

no
no
no
no
no
no
no

-.-.-.-.-.-.-.--.yes - eyes
-.no
-.no
no

no
no
-.-.-.-.-.-

51

20
2
1
1
1
1
1
1
1
1
5
1
2
1
1
1
3
3
3
1
1
2
1
1
1
1
2
4
1
1
8
1
8
1
2
2
1
1
4
1
2
1
1
2
8

Miass
Miasskoye
MirniyNikolaevka
Nizhniy Tagil
Novy Mir
Novobaturino
Novogorniy
Novoural'sk
Novoye Pole
Novyy
Kremenkul'
Nyazepetrovsk
Oktyabr'skiy
Ozerniy
OzerskPechenkino
Petrovskiy
Plast
Poletaevo
Polevoy
PolevskoyPolovinka
Pristantsionniy
RodnikiRoza
Sadoviy
Sargazy
Satka
Severnyy
Shadrinsk
ShagolShuch'eSineglazovo
Siniy Bor
Snezhinsk
Sokolovo
Sosnovka
TalicaTalovkaTayandy
Tominskiy
Travniki
Travyanoe
Trekhgorny
Troisk

87
57
48
36
355
79
4
96
281
50
41

no
no
-.no
yes
no
no
yes
no
no
yes

yes
yes
yes
yes
no
no
yes
no
yes
no
yes

no
no
yes
no
no
no
no
no
no
yes
yes

-.-.-.-.-.-.-.-.-.-.yesnono-.-.no
no
yes
no
no
no
no

-.yes
-.no
-.-.-.-.-.-.-.-

yes - eyes
no
-.yes
no
no
no
no
no
-.yes - eyes-.-.-.no-.-.-.-.-.-.-.-

175
35
43
107
15
44
69
28
17
190
200
141
73
7
47
22
154
32
192
45
95
16
35
145
17
171
281
328
24
19
55
150
191
89

yes
yes
-.yes
yes
yes
yes
yes
yes
no
yes
no
no
yes
yes
yes
no
yes
no
yes
no
yes
yes
no
yes
yes
no
yes
yes
-.no
no
no
yes

no
yes
no
no
yes
no
yes
no
no
no
no
no
no
no
yes
yes
no
-.no
yes
no
yes
yes
no
no
yes
no
yes
no
yes
no
no
no
no

no
yes
no
no
no
yes
no
yes
-.no
no
no
no
no
yes
no
no
yes
no
no
no
no
no
no
no
yes
-.no
no
yes
no
no
no
no

-.-.-.-.-.-.-.-.-.-.-.-.-.-.yes-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.no-.-.-.-

no
yes
-.no
yes
no
no
no
-.no
no
no
no
no
no
no
no
-.no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no

-.-.-.-.-.-.-.yes-.no-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.no-.-.-.-

no-.-.-.-.yes - eyes
yes - eyes
yes - eyes
-.no
no
no
no
-.yes - eyes, ears
yes - eyes
yes - eyes
yes - eyes, earsnonono
yes - eyes, ears
-.no
no
-.no
no
no
-.no
no
no
no

-.-.-.-.-.-.-.-.-.no-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.no
-.no
no

52

17
1
11
1
1
1
2
1
10
9
3

Tujmen'Tuktubaevo
TurgoyakUchalyUst'-Katav
Verkhnyaya
Samarka
Yalutorovsk
Yasnye Polyany
Yekaterinburg
Yemanzhelinsk
Zauralskiy

9

Zlatoust

365
44
92
142
209
33

no
no
no
yes
no
no

no
no
no
yes
no
no

no
yes
no
yes
no
no

-.-.-.-.-.-.-

no
no
no
no
no
no

-.-.-.-.-.-.-

no
no
no
yes
no
no

-.-.-.-.no
-.-

366
153
227
11

no
yes
no
yes

13
118

yes
no

no
no
no
yes
yes

no
yes
no
yes
no

-.-.-.yes
-.-

no
no
no
no
no

-.-.-.yes
-.-

no
no
no
yes
-.-

-.-.no
yes
no

no

no

-.-

no

-.-

yes - eyesno1.6. EMP and Electrophonic sounds(Contributed by: S. Khaibrakhmanov, A. Kartashova, S. Korotkiy, I. Serdyuk)
Bright fireballs may produce significant extremely low frequency (ELF) and very low frequency(VLF) radio emissions. If so, these electromagnetic signals would induce voltage changes acrosspower lines, called an electro-magnetic pulse (EMP), and be audible by coupling to dielectricmaterials in the immediate surroundings of the witnesses, called electrophonic sound.
Two local electricity companies in Yemanzhelinsk district, AES Invest and the InterRegional Distributive Grid Company of the Urals, reported that there were no significant voltage
surges across power lines at the time of the bolide. The electricity supply did not switch off.
Information on electrophonic noises was not gathered in a systematic fashion during the fieldstudy, but some detailed reports were obtained (Table S8). While in his office in Yemanzhelinsk,
Evgeny Svetlov, the head of the Yemanzhelinsk administration and an electrical engineer bytraining, heard a noise like the buzz of the electrical transformer during the main bolide flash.
Alexander Polonsky, a car driver, heard a noise like the roar of two fighter planes even before hesaw the bolide, while standing on a street in Yemanzhelinsk. Finally, Vladimir Bychkov, a police
programmer and physicist by training, heard a noise like the sizzle of oil in a frying pan, during
the bright stage of the bolide while he stood on a square in Chelyabinsk. The noise appeared tobe from the direction of the bolide. The noise stopped at the main bolide flash, but there was a
short sound like a clap during the flash. None of these witnesses were wearing glasses.

53

Table S8. Summary of eye witness reports of electrophonic noises (compiled by Sergey N. Zamozdra).
Name

Age
(yr)
39

Profession

Location

Sound

Time

electricalengineerAlexander
Polonsky~45

car driver

Yemanzhelinsk:
administration
officeYemanzhelinsk
streetlike a buzz of anelectricaltransformer
like the roar of
two fighter planes

Vladimir
Bychkov~43

physicist

Chelyabinsk
open area nearregional hospital

sizzle of oil infrying pan, andclap like afluorescent bulb
burning out

during themain bolide
flash
during theapproach of
the bolide
bright stageof bolide (theclap duringmain flash)

EvgenySvetlov

Environment,dielectrics
office furniture, bigwooden tables,
paper, cabinets
no data

Cars (distance ~5m), trees (distance~30 m)

From the 1,674 people interviewed during the internet survey, 198 reported hearing sounds.
The sound effects were described as hissing, as if you run fireworks noise interference, the soundof bengal light, crackle, sparking, crackling, rustle, rustling, like a whistle, squeaking, rumble,
and the sound of a passing plane (Table S9).
Table S9. Summary of electrophonic noises reported in internet survey.

Description of sound
Hiss or hissing, as if you run fireworks noise interference
Like sound of bengal light
Whistle soundSqueakCrackle or sparking or crackling
Rustle or rustling
RumbleLike passing plane

54

#
76
13
26
2
25
6
19
31

2. Damage Assessment

2.1. Injuries(Contributed by: P. Jenniskens, A. Kartashova, O. P. Popova, S. Korotkiy, I. Serdyuk,
V. Emel'yanenko, S. Khaibrakhmanov)According to tallies compiled by hospitals and communicated to us by the Headquarters of theRussian Ministry of Emergencies in the Chelyabinsk area (Table S10), 1,613 people asked for
medical assistance at hospitals, 112 people were hospitalized, 2 in serious condition. Media
reported that a 52-year old woman had a broken spine and was flown to Moscow for treatment.
There were no fatalities. All people were released from the hospital after four weeks.
Table S10. Number of people asking for medical assistance for each district as a function of range to the
airburst source (Data provided by Russian Ministry of Emergencies). Range is the distance from themeteoroid's 29.7-km point at altitude (Table S1) to the main population center in the district (in brackets).

District
Korkinsky (Korkino)
Yemanzhelinsky(Yemanzhelinsk)
Etkulsky (Etkul)
Chelyabinsk
Kopeysky
Yuzhnouralsky
Uvel'sky (Uvel'skiy)
Sosnovsky(Dolgoderevenskoye)
Krasnoarmeysky(Miasskoye)
Troitsky M.R.
Troitsky T.R.

Latitude(N)
54.895654.7536

Longitude(E)
61.3832
61.3097

range
(km)
28
29

# inhabitants(2013 Census)
63,40053,781# injured

%

102
50

0.161
0.093

54.8230
55.1692
55.102054.4436
54.442955.3460

61.5857
61.4045
61.6159
61.261761.3640
61.3408

34
45
48
54
57
59

30,697
1,156,471
142,029
37,877
31,62763,308

32
1,210
159
36
7
6

0.104
0.105
0.112
0.095
0.022
0.009

55.2841

61.890372

43,1007

0.016

54.0860
54.0860

61.5565
61.5565

96
96

27,40077,70000<0.004<0.002

Most people asking for medical attention had cuts and bruises from broken glass shattered by
the shock wave. No injuries came directly from structural damage or from traffic accidents. The
blast wave shattered windows in a wide area, both inward and outward depending on location.
Ceiling tiles and support structures in suspended ceilings were sucked down after nearby
windows broke, suggesting the action of both positive and negative pressure. Near the epicenter,55

structurally old window frames were also blown in or out. Structural damage was rare. One
aging roof collapsed at a zinc factory in Chelyabinsk and took along part of a supporting wall. A
few other older walls cracked, a confirmed case was in a private residence in Baturinskiy (part ofYemanzhelinsk), but also as far out as the village of Russkaya Techa (administration building).
The percentage of people asking for medical assistance dropped rapidly as a function of
distance from the airburst source (Table S10), according to a range (r) power-law dependence of
r-3.2±0.5, or an exponential decay with range having exponent -0.059±0.009 /km (providing abetter fit). Note that most districts fall along a north-south line perpendicular to the trajectory and
it is insensitive whether the range to the 27-km altitude point is considered, or that perpendicular
to the trajectory, except for Etkul, Korkino and Yemanzhelinsk. The majority of injuries (1,210)
took place in Chelyabinsk city (population density is about 1,130 km-2), as the city is the mostpopulated part of Chelyabinsk Oblast. The highest fraction of people asking for assistance wasnear the trajectory in the Korkino (0.16%).
The district boundaries within Chelyabinsk Oblast distort the record somewhat. Even though
Dolgoderevenskoye did not have any injuries (Table S7), 6 were reported injured in the district(Table S10). The main hospital for the Sosnovsky municipal district is there. The most damaged
areas in this district are at Tominsky, Archangelskoye, Mirny, Sargazy, and Solnechny. So, it islikely that the injured came from those villages instead. Miasskoye, too, is the center of the
Krasnoarmejsky municipal district. Again, no injuries were reported in Miasskoye itself, despite
significant damage, but injured could have come from Berezova and Oktyabrsky, elsewhere in
the district.
Of the 1,754 internet questionnaires filled out, 1109 reported no injuries and 271 left the
injury section blank. The remaining 374 reports (21.3%) mentioned 452 types of injuries orinconveniences. Most of those who responded probably did not request medical assistance. Of
the 374 people affected, 20 (5.3%) reported sunburn, 70 (19%) were temporarily blinded, 180(48%) felt eyes hurt, and 11 (2.9%) sensed retinal burns. The shock wave arrival had asignificant effect also: 24 (6.4%) had a concussion or were mentally confused, upset, or
exhausted as a result of excessive stress, and 118 (32%) of those affected were temporarily deaf.
Video records exist that show the shock wave was strong enough at places to blow people off
their feet. Flying glass and falling building debris affected a relatively small fraction of56

respondents: 18 (4.8%) had cuts and 11 (2.9%) had bruises, but no respondent reported having
had broken bones.
2.2. Heat and Sunburn(Contributed by: A. Kartashova, P. Jenniskens, O. P. Popova, S. Khaibrakhmanov,
S. Korotkiy, I. Serdyuk)
People who looked directly at the fireball had painful eyes (Table S7) and all of them closed
their eyes or turned in the opposite direction. There were no reports of lasting eye damage (lensor retina) from watching the fireball.
Throughout the survey area, there were reports of mild sunburns following the fireballsighting (Table S7). Of 1,113 respondents in the internet survey who were outside at the time of
the fireball, 25 were sunburned (2.2%), 315 felt hot (28%), and 415 (37%) felt warm. In Kokino(r = 30 km), resident Vladimir Petrov reported sunburn as severe as causing his skin to peel offsome time after the event. Korkino is almost directly underneat, ~33 km from the point in the
trajectory where peak radiation occurred. Many reports mentioned feeling heat in the neck, when
the fireball was behind the observer.

Fig S35. Left: Reports of sunburn (purple), burning retina (red), blinded for some time (yellow), and having
irritated eyes (orange). Right: Reports of being cut by glass (red) and unspecified injuries (orange).

57

The villages where heat sensations were reported were distributed throughout thesurveyed area (Fig. S35), but did not extent as far as Yekaterinburg (range r = 223 km) or
Verkhnyaya Pyshma (r = 238 km) in the north and Uchaly (r = 127 km) or Beloretsk (r = 204km) in the south. This reflects the fact that the light's flux density falls off with the inverse squareof the distance to the brightest point of the fireball (r -2). At those distant sites, the radiation flux
density was a factor of 18 (Uchaly) to 63 (Verkhnyaya Pyshma) lower.
2.3. Glass damage(Contributed by: P. Jenniskens, O. P. Popova, S. Khaibrakhmanov, A. Kartashova,
E. Biryukov, V. Emel'yanenko, A. Dudorov)
One set of data on the extent of glass damage was provided by the Chelyabinsk Regional
administration and the regional office of the Emergency Department. These data were collectedby officials in the weeks after the event to address the need for government-supported primarywindow replacement. Each listed building was inspected. That did not include secondary ones
such as balcony glazing, damage of which was still observed weeks after the event.
Damage took place in eleven municipal districts of Chelyabinsk Oblast. Data are grouped per
district in Table S11. In total, 7,320 buildings were affected, amongst which were 740 schools
and universities, 296 medical facilities, 110 cultural organizations, 48 sport facilities and 6,097
apartments and houses.

Fig S36. Examples of glass damage in pictures from Yemanzhelinsk. (A) Broken window glass. (B) Initialprotection against wind. (C) Window frames blown in. (D) Clean up. (E), (F) and (H) Lost window frames inschool. (G) Suspended ceiling sucked down. Photos by Victor I. Gubar of Yemanzhelinsk.

58

Table S11. Number of damaged buildings per district and number of buildings damaged per 1000
inhabitants (fr). Range is distance from meteoroid's 29.7-km point at altitude (Table S1) to center ofmunicial (M.R.) or city (T.R.) district. *District

MedicalSocialCultural

EducationalSportsHouses

Total

Range
(km)

Total
inhab.

fr.

Korkinsky
Yemanzhelinsky
Etkulskiy
Chelyabinsk
Kopeysky
Yuzhnouralsky
Uvel'skiy
Sosnovsky
Krasnoarmeysky
Troitsky M.R.
Troitsky T.R.

21
13
14
184
40
2
8
1
11
1
1

2
3
1
16
3
2
1
0
1
0
0

9
6
14
43
14
4
12
0
8
0
0

59
32
33
423
109
25
28
5
20
6
0

1
0
0
34
8
3
1
0
1
0
0

502
322
241
3613
903
210
154
42
92
7
11

594
376
303
4,313
1,077
246
204
48
133
14
12

28
29
34
45
48
54
57
59
72
96
96

63,40053,781
30,697
1,156,471
137,601
37,877
31,62763,308
43,10027,40077,700

9.4
7.0
9.9
3.7
7.8
6.5
6.5
0.8
3.1
0.5
0.2

*) No damage reported from these other districts in Chelyabinsk Oblast: Agapovsky (225 km),Argayashsky (76), Ashinsky (248), Bredinsky (280), Chebarkulsky (58), Chesmensky (131), Kartalinsky(212), Kaslinsky (140), Katav-Ivanovsky (212), Kizilsky (272), Kunashaksky (106), Kusinsky (132),
Nagaybaksky (180), Nyazepetrovsky (174), Oktyabrsky (99), Plastovsky (71), Satkinsky (155), Uysky(105), Varnensky (173), and Verkhneuralsky (179), with the distance from the center of the district to thepoint below the main explosion at Lat. = 54.845º, Long. = 61.412º given in brackets.

The number of houses damaged per 1,000 inhabitants (fraction, Table S11) shows an r -2.6±1.2
dependency on distance from the airburst source (r), or an exponential decay with exponent-0.050±0.009 /km. Due to a high number and density of buildings, and a large number of highrise buildings, 3,613 apartment buildings (about 44% of the total amount) were damaged in
Chelyabinsk, mainly from shattered and broken glass in windows and doors.
The most damaged districts included the most populated, Chelyabinsk and Kopeysk, anddistricts close to the trajectory (Korkino and Yemanzhelinsk). In the Korkino municipal district,
594 buildings were damaged. 7,938 wooden windows and 1,077 double pane windows werebroken in multi-apartment living houses. In Yemanzhelinsk municipal district, 376 buildings
were damaged and 2,776 windows were broken in 322 inhabited multi-apartment houses.
In the Chelyabinsk/Kopeysk area, the damage was not evenly distributed in the city. Certain
areas were damaged more than others. Also, the side of buildings damaged was not always in theshock wave arrival direction. Fig. S37 shows some examples from some areas throughout thecity, in which sides of buildings with known glass damage are marked red, those that did not
suffer damage are marked blue.

59

Fig S37 (A-G). Example areas in the city of Chelyabinsk with red marking glass damage, blue no damage. Northis up. Shock wave arrived from the South. No reliable data exist for other buildings on the maps. Sites are identified
in bottom right map, which also shows the distribution of internet responses (blue dots). This distribution reflects tosome extent the distribution of homes and internet access, but may also reflect the level of damage in the city. Note,
for example, the clustering of responses in the heavily impacted area around South Ural State University ("A").

60

Fig S38. Glass damage. Red data points were collected during the field survey, purple data were provided by the
Emergency Department. Open circles indicate that no glass damage occurred.

The most damaged settlements according to official data are shown by purple symbols in Fig.
S38. The damage area has an extent of about 180 km from north to south and 80 km from east to
west, but is shaped along a curved arc centered on Yemanzelinsk, extending from the northernparts of Chelyabinsk as far south as Troitsk.
Red data points in Figure S38 are collected during the field survey, purple data points arevillages that reported damage through the Ministry of Emergencies at Chelyabinsk. Open circles
are sites where no damage occurred. The red points include many villages that had only a few
windows damaged (usually in school buildings). Hence, the inner contour of the purple points
may represent a higher overpressure than the outer contour of the red sites.
The value of overpressure, Δp, needed to break window glass is dependent on the glass
thickness and surface area. These values are not different between windows in Russia (mostaffected buildings being from the 20th century) and other locations in the world. Glasstone andDolan [84] estimated the overpressure which caused essential glass damage at about Δp~3,5005,000 Pa. According to Mannan and Lees [87], an overpressure of about Δp~700 Pa is able to61shatter 5% of glass windows, Δp~1,400 Pa would break 50%, and Δp~3,500 causes damage toabout 90% of glass windows. This suggests that a value of Δp~500 Pa would describe the extent
of the damage area where just a few windows were broken (Table S7A), while Δp~1,000 Pa
would result in significant window damage as in the central core of Fig. S38 [88].
2.4. Model of the shockwave(Contributed by: V. V. Shuvalov, O. P. Popova, Y. S. Rybnov)
To model the damage on the ground, numerical modeling of explosions with different energies,
and at different altitudes in the atmosphere, were conducted. The gasdynamical code SOVA
(SOlid Vapor Air, [89]) was applied, with a numerical grid density of 1000×500 points. Realistic
atmospheric densities, pressures, and temperatures were used as input to the model. The standard
atmosphere model CIRA (COSPAR International Rerence Atmosphere) was used to include thevariation of atmospheric density and temperature with altitude. The Kuznetsov [90] table giving
the equation of state of air was used. The maximum pressure at different points on the ground
was calculated, which took into account the reflection of the shock wave by the surface.

Fig. S39. The relative pressure versus distance R from the ground-projected position of the point source
explosion, normalized to 1 atmosphere pressure, that would be caused by explosions with different energy
energy (E) ranging from 3 to 300 kT TNT and altitudes (H) ranging from 5 to 25 km. The horizontal line
corresponds to an overpressure of Δp~500 Pa.

62

A point-source explosion at 25 km altitude with energy of 300 kT equivalent TNT is able tocause an overpressure of Δp~500 Pa over an area with diameter of ~60 km (Fig. S39).
In practice, the energy is not released in a single explosion during flight and fragmentation of
the meteoroid through the atmosphere. A number of numerical simulations were conducted that
attempted a more realistic release of energy along the trajectory. In each model, the total kinetic
energy of the entering asteroid was fixed at 300 kT TNT. An entry angle of 16.5 degree withrespect to the horizon was assumed (observed: 18.3º). The observed fireball had three main
moments of fragmentation and corresponding flares (Fig. S16), hence three principal moments ofenergy release were considered. The last part of the trajectory below 21 km was not taken into
account, because the radiation was fainter in this part of trajectory and the meteoroid mass andvelocity had decreased significantly.
Three different cases were considered. In all cases the energy was released along the
trajectory with a time delay corresponding to the meteoroid motion. For these models, thenumerical grid has 500×250×250 points along the X, Y and Z axes. The X axis was taken along
the trajectory in a direction opposite to the meteoroid motion, Y was taken perpendicular to the
trajectory, while Z was vertical in upward direction.
In case I, all energy was released in one point X,Y = (+20, 0) km at Z = 31.7 km altitude,
which corresponded to the main flare.
In case II, all energy was released along the trajectory between points (+100, 0) at 55 km
altitude and (-16, 0) at 21 km altitude, and this energy release was taken to be proportional to the
air density. Such energy release corresponded to a meteoroid flight with constant cross section,
no disruption and negligible ablation, and without deceleration.
In case III, half of the energy (150 kt TNT) was released along the trajectory as in case II,
30% of energy (90 kt) was released in the first flare at (+20, 0) at 31.7 km altitude, 15% ofenergy (i.e. 45 kt) during the middle flare at (0, 0) at 25.8 km altitude and the final 5% (i.e. 15 kt)
was released during the small flare at the end of the considered trajectory (-16, 0) at 21 km
altitude. These altitudes correspond to early estimates of the entry trajectory [46].
The relative pressure distribution in the plane (X, Z) is given in Fig. S40 for case III at threedifferent time steps. Time t=0 corresponds to the end of energy release. At all times, the63spherical shock waves from the three individual flares and the ballistic shock wave caused by themeteoroid's subsonic flight are well distinguishable.

Fig. S40. The relative pressure Р/Р0 distribution (P0 is the pressure at the surface) for case III, case of 300
kt TNT continuous energy release with three flares (see text).

64

Fig. S41. The relative density ρ/ρo distribtuion (ρo being the density at the Earth surface) at the moment
when the shock wave reaches the surface. The contour line corresponds to 0.1% compression. Case II –300 kt TNT energy is released continuously along the trajectory (proportionally to the air density).

The ballistic shock wave has a conical shape with a small opening angle due to the highmeteoroid velocity (taken at 18-19 km/s) compared to the sound velocity (0.3 km/s), at which
speed the quickly decaying shock wave is spreading. It is important to note that the moment of
the shock wave arrival at some point on the ground does not depend on the position of the main
flare along the trajectory. To a good approximation, sound arrives at a location from the nearest
point to the trajectory (but see below).
The relative density distribution in the plane (X, Z) is given in Fig. S41 for case II at the
moment when the shock wave reaches the surface. At this time, the meteoroid wake alreadystarted to show billowing due to the development of instabilities.

65

Fig. S42. The relative overpressure on the ground along the trajectory for case I (black dashed curve),case II (grey curve), and case III (black solid curve). Forward direction is towards the left.

The relative overpressure on the ground along the trajectory is given in Fig. S42. Projected to
the Earth surface (X, Y plane), the overpressure contours of Δp>500 Pa and Δp>1000 Pa areshown in Fig. S43A. This pattern should reflect the observed area of broken windows.

Fig. S43A. For three considered cases, shown is the surface area corresponding to overpressures of
Δp>500 Pa (relative overpressure >0.005; colored grey) and Δp>1000 Pa (relative overpressure >0.01,
colored black). Case I: left panel; Case II: middle panel; Case III: right panel.

66

In all three considered cases, the surface area on the ground that was affected by theshockwave is very similar, determined mainly by the total amount of energy released. The shapeof the overpressure distribution is determined by the details of the energy release along the
trajectory. This may be explained by the fact that in all cases the main part of energy is released
at a similar high altitude and the size of the energy source is comparable (or even smaller) thanthe distance to it. In the case of a point energy source (case I) the damaged area has a circulargeometry. In both cases considered where the energy source is stretched along the trajectory(cases II and III) the area of damage is elongated in the direction perpendicular to the trajectory.
Non-constant energy release (case III) is needed to match the observed pattern in Fig. S38.

Fig. S43B. Surface overpressures from total initial energy 300 kT (a, b) and 520 kT (c, d) of TNT. Leftpanels (a, c) are deposition Case III and Case IV (see below), while right panels (b, d) are Case V. Gray isoverpressure Δp>500 Pa (relative overpressure >0.005), black corresponds to Δp>1000 Pa (relative
overpressure >0.01).

In case III, which has the continuous energy release with three flares, the peaks ofoverpressure are evident in the places where the shock waves from individual flares intersect67

(Fig. S42). In case II (continuous energy release along limited trajectory), there is only one
pronounced peak, which corresponds to the transition from cylindrical explosion to the sphericalone. In case I, the peak is not sharp and its thickness has about the radius of curvature of thearriving shock wave. Case III also best describes the rapid decrease of overpressure in forward
direction and the long tail of overpressure observed towards the back of the trajectory during eye
witness interviews (Fig. S38). The Δp = 500 Pa contour for the 300 kT impact reaches to ~75
km. Using the scaling law distance D ~ E1/3 [84], implies that an energy of E ~ 520 kT would
cause an airburst that reaches to 90 km from the trajectory.
In order to check this scaling law, we calculated the overpressure on the surface for 520
kt TNT total meteoroid energy (Fig.S43B). The altitudes of energy deposition were now basedon the trajectory determined in this work (Case IV). Similar to Case III, half of the energy (260kt TNT) was released along the trajectory, 30% of energy (156 kt) was released in the first flareat (+18.6) at 29.7 km altitude, 15% of energy (i.e., 78 kt) during the middle flare at (0, 0) at 23.9
km altitude and the final 5% (i.e., 26 kt) was released during the small flare at the end of theconsidered trajectory (-17.2km) at 18.5 km altitude.
One more case (Case V) was modeled under the assumption that all energy was releasedin accordance with the bolide light curve (Fig. S16, S18A). Results are shown in Fig. S43B. This
results in a more extended area perpendicular to the trajectory. At 520 kt TNT, the overpressure
contour (P>500 Pa) reaches 120 km in this direction, compared to 102 km for 300 kt TNT Case
III. So far, case V is our best effort in matching the observed damage area (Fig. 3, main text).
The results confirm that the total affected area is roughly scaled with the total energy andthe shape of the area is dependent on features of assumed energy release. An energy release inproportion to the observed lightcurve results in a more narrow overpressure zone along the
trajectory and a more extended zone in perpendicular directions.
However, the manner of energy release affects not only the pressure pattern on the
ground (Fig. S43A, 43B), but also the structure of disturbances in the air and the observed
structure of the meteor wake (Fig. S41). The relative pressure Р/Р0 distribution for Case V (520kt TNT) is shown in Fig. S43C. Compared to Fig. S40 (Case III, 300 kt TNT), there are
noticeable differences in the pressure pattern.

68Fig. S43C. The relative pressure Р/Р0 distribution (P0 is the pressure at the surface) for Case V (520 kt
TNT released in proportion to the light curve).

Blast Wave Arrival Times(Contributed by: V. V. Shuvalov, O. P. Popova, Y. S. Rybnov, and P. Jenniskens)
A blast wave is a particular type of shock wave caused by the deposition of a large amount ofenergy in a small very localized volume, a propagating disturbance characterized by anextremely rapid rise in temperature, pressure, and density [91]. Blast wave arrival times can be
estimated assuming that the wave expands with a constant velocity equal to the sound speed. Our
numerical simulations show that this is a good assumption for the blast wave when an airburst
occurs at high altitude [91]:

69

if

Eq. S4

if

Eq. S5Here t0 is counted from the time when the meteoroid reaches the terminal point, c0 is thesound speed, shock angle α = β - arcsin (co/U), where U is the meteoroid velocity, and β is the
trajectory entry angle (to the horizon). The meteoroid moves from right to left in the plane Z0X,
whereby (0,0,z0) are the coordinates of the terminal point. Terminal point here means the end of
the main energy release by the meteoroid, in the case of Chelyabinsk this corresponds to thebrightest part of the meteoroid lightcurve. The comparison of arrival time determined based on
Eqs. S4-S5 and gasdynamical numerical modeling demonstrates satisfactory agreement (Fig.
S44). By comparing these results to observed arrival times, it is possible to determine the altitude
where most meteoroid energy was deposited.

Fig. S44. The comparison of arrival time estimates based on Eqs.S4-S5 (grey lines, assuming a terminal
altitude of 15 km), compared to results from gasdynamical numerical modeling (magenta lines). Time iscounted from the moment when the blast wave reaches the ground just under the terminal point.

Eighteen time-calibrated video records (at 10 frames per second) provide a record of thearrival times of the shockwave in the Chelyabinsk/Kopeysk area (Table S12). Most reliable arethose where the shockwave shakes the camera, or moves smoke, car exhaust, or cables in the70field of view. Less reliable are those that show car alarms go off, because they tend to have avariable delay of a few tenths of seconds (or much more).
Table S12. Summary of shock wave arrival times from video records. Range is distance from site to theapproximate 23.9-km point (Table S1) at altitude.
Video
#
90
30
97
171
177
31
237
417

Site

Lat. (N)Long. (E)61.29611
61.41418
61.60240
61.61304
61.39614
61.38184
61.40257
61.43558

Alt
(m)
226
232
213
211
230
229
229
223

Range
(km)
42
43
48
48
44
44
44
46

Time UT(±0.1s)03:22:52.8
03:22:53.1
03:22:54.8
03:22:55.4
03:22:56.2
03:22:56.8
03:22:57.0
03:23:00.4

Chelyabinsk
Chelyabinsk
Kopeysk
Kopeysk
Chelyabinsk
Chelyabinsk
Chelyabinsk
Chelyabinsk

55.17098
55.14344
55.11727
55.11686
55.15866
55.16260
55.16014
55.16818

258
160
329
452
30a
216
60
35
105

Chelyabinsk
Chelyabinsk
Chelyabinsk
Chelyabinsk
Chelyabinsk
Chelyabinsk
Chelyabinsk
Chelyabinsk
Kurgan55.17832
55.1722155.19525
55.18404
55.19009
55.18320
55.19177
55.25174
55.46484

Detection

61.35922
61.45356
61.32239
61.39359
61.35732
61.38599
61.38485
61.40274
65.26888

215
234
258
228
252
229
223
251
82

44
46
46
46
45
46
46
52
272

03:23:00.6
03:23:02.0
03:23:02.1
03:23:02.8
03:23:03.1
03:23:03.3
03:23:05.9
03:23:24.8
03:28:01.7

car alarms
car alarmswinging cable
cable, billboard
car alarm
car alarms
camera shakes
car exhaust,
cablescable
cable cam. shakewaving banner
balloons waving
camera shakes
cablewaving banner
car exhaust, cableswinging cable

2
Pervomayskiy
54.87060
61.17369
6
Korkino54.89089
61.39966
7
Yemanzhelinsk 54.75664
61.30380*) relative to peak luminosity at 03:20:32.2 UT.

275
249
227

23
30
30

03:21:47.8*
03:22:00.8*
03:22:01.7*

car shaking
car shaking
car shaking

We use this simplified approach to compare blast wave arrival time with data from Table
S12. An entry velocity of 18.6 km/s and an entry angle of 18 degrees to the horizon wereassumed, but a 19.15 km/s entry speed give very similar results. The wind and dependence ofsound velocity on atmospheric profile were neglected, as well as the difference between thesound speed and the shock wave velocity near the source (blast radius). The difference between
real and model arrival times may reach 2-5 s dependent on the atmospheric conditions. For mostvideo cameras located in Chelyabinsk and Kopeysk, the time delay Δt between maximum
brightness and blast wave arrival is about 140-151 s (Table S12, Fig. S45A). In Kurgan, about
270 km from the chosen trajectory point, Δt ~450 s (Fig. S45C). The smallest values of Δt are
obtained for Pervomayskiy, Korkino and Yemanzhelinsk: Δt ~ 76-90 s.

71For a given entry velocity and angle, the blast wave arrival time is dependent on the assumed
terminal altitude of energy release (z0). Fig. S45A shows the arrival times corresponding to z0 =29.7 km, at the peak of the lightcurve profile (Fig. S16). It is reasonable to suggest that mostenergy is deposited here, but that does not appear to be the case. The wave arrives too late in
Chelyabinsk (Δt ~ 160 s) and the sites of Pervomayskiy, Korkino and Yemanzhelinsk near the
trajectory (Δt>100-110 s). Also, the wave arrived earlier in Korkino than Pervomayskiy,
opposite to observations (Table S12).

Fig. S45A. Blast wave arrival times from a conical source with 29.7 km terminal altitude, comparing
those calculated (black lines) and observed (red markers). The yellow line is the meteoroid trajectory.

It appears that energy release down to lower altitude is important. With the source at 23.9 km
altitude at the peak of the third flare (Fig. S45B), and after increasing the arrival times by 1.2 s toaccount for the relative time that the meteoroid arrived at this altitude (Table S1), the calculated
arrival times are in good agreement in the Chelyabinsk-Kopeysk area, but the arrival times in
Pervomayskiy and Korkino are 4 s late. That is well within the range of our estimateduncertainty. Hence, the energy deposition past peak brightness and down to 23 km significantly
contributed to setting the arrival times for the shock wave.

72

Fig. S45B. Same as Fig. S45A, for a conical source with 23.9 km terminal altitude.

Fig. S45C. Expanded view of Fig. S45B, for a conical source with 23.9 km terminal altitude.

73

A lower terminal height of 18 km (after adding 2.5s to account for flight time) would also
result in reasonable agreement with arrival times at observing locations, because those aredetermined by earlier parts of the trajectory. There are no data further forward along the
trajectory that could measure the contribution from this altitude. In Chebarkul, even a smoke
cloud in video #105 (Table S3) did not react to the shockwave.
A conically shaped blast wave (see for example Fig. S40) provides agreement with the blast
arrival time in Kurgan (Δt = 450 s, Fig. S45C), whereas a spherical energy source essentiallyoverestimates the propagation time. Kurgan is located 272 km from the source region and theshock wave arrival was measured by the response of a swinging cable right in front of the video
security camera (Table S12).
In conclusion, comparing the arrival times from conical sources with different terminal
altitudes to those observed at different locations demonstrated that a conical source cansatisfactory describe the observed blast wave arrival times, but only if the energy deposition
continued down to 23 km altitude. The deposition of the energy, which is responsible for theformation of the blast wave, occurred spread along the trajectory. Only a negligible fraction of
the initial kinetic energy (and mass) was probably deposited below 23 km.
2.5. Structures hit by Falling Meteorites(Contribution by P. Jenniskens, O. P. Popova)
Small meteorites were found on the roof of a building in Emanzhelinka. Only one structure, asecondary building owned by the Biryukovy family in Deputatskiy, was damaged by a fallingmeteorite. The meteorite created a gap at the edge of a corrugated plate (arrow in Fig. S46) and
was found in fragments at the foot of thebuilding. No injuries occurred.

Fig. S46. The owners of the property in
Deputatskiy (left) show the meteorite responsible
for the structural damage (arrow) to one of us(O.P., center).

74

3. Recovered Meteorites
3.1. Meteorite Recovery.
(Contributed by: S. Khaibrakhmanov, A. V. Korochantsev, M. Yu. Larionov,V. Grokhovsky, P. Jenniskens, A. Kartashova, O. Popova, D. Glazachev)
A series of dedicated searches for meteorites were organized by the Chelyabinsk State
University, the Ural Federal University in Yekaterinburg, and by the Vernadsky Institute ofGeochemistry and Analytical Chemistry of the Russian Academy of Sciences in Moscow
between February 19th and 25th. In these early searches, the exact (< 10 m) location of most
meteorite finds was not documented. The meteorites with exact find locations are listed in Table
S13. The searches were continued after the snow melt on April 12th, resulting in many more
finds with known locations. Meteorites studied in this work are identified in Fig. S47.

Fig. S47. Fragments of Chelyabinsk (C2 - C6) analyzed in this study. Find locations are marked. C2 is anoriented meteorite, backside shown.

Fig. S48. Confirmed locations of meteorite finds. Numbers indicate meteor altitude in km.

75

Table S13. Chelyabinsk meteorites with known masses and find locations. They are listed in the orderthat the information was provided. Those labeled with an asterisk are studied in this work (Fig. S47).
C#
1
2*
3*
4*
5*
6*
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Mass (g)-.5.83
4.46
4.84
1.58
0.46
1,060
430
150
470
11.41
18.41
6.9
1,800
3.6
2.8
382
125
50
56
126
200
156
420
15
141
142
151
320
760
122
190
1,748
10
256
980
198
1,000
252
201
450
715
45
133
95
25
1,050
290
170
501

Latitude (N)54.8388
54.8273
54.802254.802254.802254.802254.8698
54.875254.842754.851454.871154.872054.874254.8598
54.842054.8463
54.850254.8448
54.8376
54.8347
54.842854.842854.861754.833154.861054.8760
54.874854.862054.874154.8745
54.8732
54.850354.884554.8440
54.8789
54.8850
54.8828
54.8776
54.8885
54.8805
54.873454.8592
54.8589
54.8550
54.8533
54.8588
54.874454.872454.880754.8761

Longitude (W)61.124161.159461.2756
61.2756
61.2756
61.2756
60.9672
60.9551
61.0828
61.020960.8533
60.8555
60.8233
60.9348
61.103661.1084
61.105461.1066
61.0925
61.0968
61.102961.102961.1356
61.0879
60.990960.9782
60.984460.9978
60.9775
60.980161.101761.0892
60.8176
61.0664
60.860160.8660
60.8755
60.921060.8948
60.981060.989361.0308
61.029761.0575
61.081661.0234
60.900260.9068
60.993160.8972

Altitude (m)
280
282
256
256
256
256
281
306
308
302
298
314
317
298
297
297
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300

76

Date Find
2/15/2013
2/19/2013
2/19/2013
2/19/2013
2/19/2013
2/19/2013
4/15/2013
4/16/2013
2/26/2013
2/28/2013
4/13/2013
4/13/2013
4/13/2013
4/23/2013
2/22/2013
2/22/2013
2/21/2013
2/22/2013
2/23/2013
2/23/2013
2/23/2013
2/23/2013
2/24/2013
2/24/2013
4/15/2013
4/15/2013
4/15/2013
4/15/2013
4/16/2013
4/16/2013
4/17/2013
4/19/2013
4/20/2013
4/22/2013
4/22/2013
4/22/2013
4/23/2013
4/23/2013
4/23/2013
4/24/2013
4/24/2013
4/25/2013
4/25/2013
4/26/2013
4/26/2013
4/28/2013
4/30/2013
4/30/2013
5/2/2013
5/3/2013

Finder
Biryukovy (house hit)
V. Kubrin
A. Dudorov
student CSU
S. Khaibrakhmanov
S. Khaibrakhmanov
V. Bogdanovsky
V. Bogdanovsky
E. Tvorogov
E. Tvorogov
S. Khaibrakhanov
A. Bukhalov
A. Zhilkin
M. Pen'kova
S. Petukhov
I. Talyukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin
S. Petukhov/I. Tayukin

51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106

40
6.0
5.9
18
50
23
503
1,786
186
3,400
21.7
300
102.5
354
164.2
147.5
4.2
30.0
22.1
36.9
439
35
198
14.9
30
107
14.9
439
27
1,220
361
593
84
448
200
76
55
150
97.9
82.5
24.5
963
23.7
136
1,845
60
117
150
110
356
52
290
502
201
560
200

54.8371
54.8372
54.8372
54.8372
54.871954.8704
54.871854.904154.8705
54.901154.873154.8732
54.8765
54.875454.874154.8689
54.862954.852054.864854.8696
54.8688
54.871054.870854.869354.8687
54.8687
54.8676
54.869754.8691
54.870154.872254.871654.8706
54.869954.8652
54.8670
54.8686
54.8747
54.882354.879954.8792
54.8740
54.871854.8724
54.8784
54.865354.862554.8638
54.879754.8772
54.8772
54.8772
54.881854.8777
54.885354.8863

61.170161.169961.1687
61.1684
60.9666
60.9565
60.9677
60.7867
60.9769
60.7575
60.9668
60.9557
60.954360.952860.9676
60.9778
60.951460.9893
60.952260.960760.9679
60.930760.930760.934260.9348
60.942160.941260.9275
60.9266
60.914460.9262
60.8875
60.893960.952060.962760.9482
60.9296
60.9496
60.964260.9649
60.952860.954260.9562
60.9170
60.7943
60.9905
61.003161.0193
60.9368
60.9351
60.932260.9304
60.9152
60.914360.902760.8981

300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300

77

2/25/2013
2/25/2013
2/25/2013
2/25/2013
4/14/2013
4/14/2013
4/14/2013
5/15/2013
4/15/2013
4/26/2013
4/15/2013
4/15/2013
4/15/2013
4/15/2013
4/15/2013
4/19/2013
4/19/2013
4/19/2013
4/19/2013
4/19/2013
4/19/2013
4/20/2013
4/20/2013
4/20/2013
4/20/2013
4/20/2013
4/20/2013
4/20/2013
4/20/2013
4/20/2013
4/20/2013
4/21/2013
4/22/2013
4/22/2013
4/22/2013
4/23/2013
4/23/2013
4/23/2013
4/24/2013
4/24/2013
4/24/2013
4/24/2013
4/24/2013
4/24/2013
4/24/2013
4/24/2013
4/24/2013
4/24/2013
4/29/2013
4/29/2013
4/29/2013
4/29/2013
4/29/2013
4/29/2013
4/30/2013
4/30/2013

Vernadsky Institute
Vernadsky Institute
Vernadsky Institute
Vernadsky InstitutelocalslocalslocalsV. Bogdanovsky
localsA. Usenkov
localslocalslocalslocalslocalslocalslocalsV. Bogdanovsky
localslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalsV. Bogdanovsky
localslocalslocalslocalslocalslocalslocalslocalslocalslocals

107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162

133
53
150
250
175
150
590
303
902
190
600
515
490
125
1,430
3,070
520
41
360
420
200
548
25
5.8
82.9
219.6
76
29.6
16.1
75.8
32.4
49
57.9
153.5
5
49.7
16.2
1.9
11.4
13.9
303
10.2
12.2
163
86.6
14.1
100
152.9
1,410
493
19.4
376
68.8
38.1
28.8
63.8

54.8395
54.8592
54.8760
54.8780
54.8763
54.8445
54.8798
54.871954.880354.8830
54.883654.8877
54.8849
54.874654.907154.903754.8855
54.839354.8694
54.884454.885454.900754.8355
54.8355
54.8567
54.8586
54.853954.863954.855154.855954.859454.8585
54.8556
54.8379
54.8473
54.850354.850354.850354.8304
54.8452
54.865954.865954.867754.8676
54.868354.8685
54.8632
54.882254.872254.884854.8585
54.8565
54.895654.861354.8652
54.8628

61.1188
61.074660.9873
60.952960.977761.1540
61.021360.9675
60.9365
60.9288
60.9267
60.9158
60.922160.952360.8158
60.8088
60.8134
61.1459
61.091961.0857
61.0676
61.0625
61.1088
61.1088
61.121261.0938
61.1246
61.1246
61.1008
61.101661.122261.1076
61.1026
61.1084
61.1103
61.0988
61.0988
61.0988
61.0988
61.0989
61.017161.003561.012061.012961.013861.0133
61.0053
60.974460.973660.9683
61.019461.0174
61.010761.0174
61.0343
61.0302

300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
298
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300

78

4/30/2013
4/30/2013
5/3/2013
5/3/2013
5/3/2013
5/3/2013
5/7/2013
4/15/2013
5/9/2013
5/9/2013
5/9/2013
5/10/2013
5/10/2013
4/14/2013
5/12/2013
5/13/2013
5/13/2013
5/29/2013
5/29/2013
5/29/2013
5/29/2013
5/29/2013
4/12/2013
4/12/2013
4/13/2013
4/13/2013
4/13/2013
4/13/2013
4/13/2013
4/13/2013
4/13/2013
4/13/2013
4/13/2013
4/14/2013
4/14/2013
4/16/2013
4/16/2013
4/16/2013
4/16/2013
4/16/2013
4/17/2013
4/17/2013
4/17/2013
4/17/2013
4/17/2013
4/17/2013
4/17/2013
4/18/2013
4/19/2013
4/19/2013
4/20/2013
4/20/2013
4/20/2013
4/20/2013
4/22/2013
4/22/2013

localslocalslocalsV. Bogdanovsky
localslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalsV. Bogdanovsky
V. Bogdanovsky
A. Filimonov
A. Prokopenko
A. Prokopenko
A. Prokopenko
A. Prokopenko
localslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocals

163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178

24.9
68.7
358.5
350.2
52.5
278
2,180
1,889
125.2
1,510
118
3.6
129
28
148
10

54.8559
54.882154.886154.886154.874454.8758
54.879754.8560
54.8786
54.8766
54.884154.8866
54.8774
54.889054.8856
54.880961.0170
60.8874
60.912460.9124
60.8939
60.894660.9099
60.910760.8930
60.909460.8578
60.9092
60.9082
60.824160.854160.8635

300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300

4/22/2013
4/23/2013
4/23/2013
4/23/2013
4/23/2013
4/23/2013
4/23/2013
4/23/2013
4/23/2013
4/23/2013
5/23/2013
5/29/2013
5/29/2013
6/15/2013
6/20/2013
6/21/2013

localslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalslocalsK. Ryazantsev
K. Ryazantsev
K. Ryazantsev

Table S14. Chelyabinsk meteorite collections with approximate find locations.
#

Total
mass (g)Mean(g)

Range (g)N

Latitude(N)

Longitude (W)

A
B
C
D
E
F
G
H
I
J

1.99
166
1,300
780.0
169
5,000
15.45
-.133
483

0.039
5.9
5.2
120
3.68
30.9
0.4
-.133
12.0

0.06-0.95
0.7-20.6-.20-300
0.04-100
1.4-120.5
0.04-1
0.5-5
133
0.4-37

51
28
~250
9
46
>9
41
50
1
40

54.959454.802254.8273
54.802254.827154.802254.812954.785254.840254.8461

60.322161.2756
61.159461.2756
61.150261.2756
61.281461.370361.102061.1029

K
L
M
N
O
P
Q
R
S
T
U

235.0
2.2
7
4
10
>86
495.7
2,989.3
309.7
647.6
556.5

2.6
1.1
2.3
0.4
<0.1
-.1.72
44.6
1.35
27.0
92.8

0.2-35
1-1.2
0.5-5
0.2-3
0.1-3
0.04-86
0.58-11.1
0.39-18060.23-20.25
0.53-29.70
7.52-299.5

90
2
3
9
100+
many
288
67
229
24
6

54.822254.760454.760454.8138
54.770254.7965
54.80454.85854.81654.84354.86061.1667
61.351961.351961.462261.4980
61.251461.25160.93561.30361.12760.977

Altit
ude
(m)
318
256
282
256
279
256
245
230
291
295

Date
Find

Finder

2/17
2/19-25
2/19-25
2/19-25
2/19-25
2/19-25
2/19-25
2/19-25
2/23
2/23

276
225
225
230
225
262
251
291

2/23-24
2/19-25
2/19-25
2/19-25
2/19-25
2/19-25
2/22-23
2/22-23
2/22-23
2/19
4/21

UrFU - Larionov
CSU - Dudorov
V. Kubrin
A. Khaibrakhmanov
E. Chayko
T. Iljin
L. Kuznetsova
Mrs. Pivovarova
S. Zamozdra
S. Buchkov /D. Rakhmankulov
A. Wahl
O. Panova
local children
local
local
localsR. Kolunin
L. Alexandrov:
S. Malagamba
M. Larionov
N. Kruglikov

286
286

Other information about the distribution of meteorite falls comes from the approximate
location (±0.5-1 km) of meteorite finds in collections (Table S14). Photographs of meteorite
collections were taken with a scale and the finder was asked to identify the approximate findlocation. Unless specified otherwise, only meteorite collections that could be photographed areincluded in the list.

79

In examining the large Kubrin collection (Table S14), it became clear that half of the larger
3-5 cm sized meteorites found near Bereznyaki were oriented in shape. One example is meteorite
C2, shown in Figure S47, which is a thin, flat, meteorite that travelled with its flat side forward.
Meteorite Recovery from Snow(Contributed by: P. Jenniskens, A. V. Korochantsev)
Meteorites fell in snow and were found several days after the fall by looking for holes anddigging in search of 10-15 cm long ice cones that encapsulated the meteorites (Figs. S49-S50).
Snow fall on February 25 prevented further meteorite searches until later in the season.

Fig. S49. (A) Meteorite found during the Vernadsky Institute, RAS, field campaign; (B-C) Hole insnow layer and ice cone attached to meteorite; (D) Chondritic meteorite; (E) Impact melt.

Fig. S50. (A) Hole from falling meteorite in snow layer with ice cone exposed; (B) The meteorite isrecovered at the bottom tip of the ice cone. Photo's from a video by V. Kubrin.

The exact mechanism generating the observed ice cones is not readily understood; however,they may be created by the following process. Competing processes make a freshly fallen snow
layer more powdery over time, closely related to the bond-to-grain ratio in snow [92]. At80

temperatures below freezing, larger and more dendritic grains in low density dendritic snow
morphologies undergo a growing metamorphosis and form stronger bonds over time bysintering, but at the same time result in the formation of unbounded small rounded particles. On
the surface, on the other hand, the temperature fluctuations by exposure to sunlight cause snow
crystals to undergo a disintegrating metamorphosis, by becoming rounder in shape to minimize
free energy, which sinter to form stronger bonds. This process is responsible for forming an icy
crust [92, 93]. We found layers of icy crust at different levels in the snow pack.
In the days following the fall, wind swept powdery snow filled the lower half of the holes,
which tended to be 3-4 times wider than the meteorite. Winds could have rounded thesnowflakes by loosing their points. Temperature fluctuations then made them susceptible to thetype of disintegrating metamorphosis found near the surface by sintering into larger roundedgrains. Moreover, vapor diffusion is the main mechanism leading to sintering [92] and perhaps
sintering was intensified by a higher humidity in the tunnels. This turned the snow into ice
popsicles, isolated from the surrounding powdery snow.
Mass Distribution of Fallen Meteorites and Total Fallen Mass
(Contributed by: A. E. Dudorov, S. A. Khaibrakhmanov, A. E. Mayer, D. D. Badyukov,
and P. Jenniskens)
Here, we consider a total of 939 meteorites with known recovery masses, totaling 7,767 g, withindividual samples ranging from 0.04 to 300 g. Most of these meteorites were found near
Emanzhelinka and Deputatsky and collected during the field search by the Vernadsky Institute
RAS and Chelyabinsk State University.
The mass distribution, normalized to unity (Fig. S51), is close to a log-normal mass
distribution function:(Eq. S6)
where A, µ and σ are the distribution parameters. A least-squares fit to the histogram gives: A =0.60 ± 0.02, µ = 0.27 ± 0.02, σ = 0.67 ± 0.02. (dashed line in Fig. S51). The log-normal
distribution implies that the process leading to the production of these fragments happened
randomly and in a cascading way [94]. In some cases too, the strewn-field mass distribution was
well described by a log-normal distribution [95].
81Fig. S51. Meteorite mass distribution, histogram with a log-normal fit (dashed line).

Atmospheric drag causes size-sorting along the trajectory and the distribution does notinclude the >300 g fragments found further west. On the other hand, if this same log-normal
distribution extends to masses as large as 1.8 kg, the largest fragment found just west of
Deputatskiy (Table S13), then the total fallen mass comes out to >789 kg. This is a lower limit
because larger masses may have fallen as part of this population of fragments.
Table S13 and S14 lists a total mass of just over 69 kg, representing a meteorite line density(mass per kilometer along the trajectory) of about 2 kg/km. This is a lower limit. An estimate of
the actual value can be made from the large collection of Vyacheslav Kubrin (Table S14), whoestimated his finds represented only 10% of the total amount of meteorites recovered from a
triangular area of 0.23 km2 centered on longitude 61.1636ºE. This translates to a meteorite
density of 57 kg/km2 at that location. If the meteorite strewn field has an effective width of 2 km
[96], then the line density is 114 kg/km, assuming that the search area is near the center of thestrewn field. Previous falls found a constant line density along the trajectory [96] which, for a
40-km long confirmed fall area out to the location of the 1.8-kg fragment, translates to a total
fallen mass of approximately 4,600 kg between Aleksandrovka and the location west of
Deputatskiy where the 1.8-kg fragment was found (Fig. S48). The accuracy of this number
depends on the accuracy of the recovery efficiency, the effective width of the field, and to someextent if Kubrin's finds were made at the center of the strewn field.
This does not include material surviving from disruptions below 29.7 km altitude. Light
curve modeling (Sect. 1.2) suggested that larger fragments survived down to the ground, the82largest about 100-400 kg (recovered: 600-650 kg). The fragment mass distribution varied fromone model to another, but there could be about 1,000 kg more in 20-2000 fragments in the area
up to 70 km west along trajectory from the point of maximum brightness (line density ~14kg/m). The number density of these fragments is lower than that for the gram-sized fragments. If
so, the total fallen mass is about 4,000-6,000 kg (i.e., 0.03-0.05% of the initial mass).
Table S15. Ground-projected displacement and the time it takes meteorites of different mass to fall to theground from 29.7 km altitude, assuming a spherical shape with density 3.3 g/cm3 (Sect. S4.2), dragcoefficient Cd = 0.43 if Mach number Ma < 0.5, Cd = 1.0 if Ma > 1.4, and otherwise Cd = 0.715 + 0.285
sin [3.1415 (Ma/0.9 - 1.05)], and prevailing winds (Sect. S1.4). Lateral velocity from fragment interaction
after disruption [97], responsible for the lateral spreading of the strewnfield, was not taken into account.

Mass
(kg)

Time
(s)

Measured Impact
Time (s) Speed(m/s)

Perpendicular
Displacement(km)*

Along Track
Displacement(km)**

Measured Along
Track Displacement(km)***

0.0001 758
-.17
-12.4
-9.0
-6
0.001
514
-.25
-8.3
-1.3
6
0.01
347
-.37
-6.2
10.7
18
0.1
235
-.55
-3.8
20.4
33
1.0
158
-.82
-2.6
32.4
43
10
107
-.124
-1.8
45.6
-.100
73
-.184
-1.4
59.4
-.600
53
62.5
225
-1.0
70.7
67
*) Negative is south of track; **) If no further ablation; ***) Relative to 29.7 km altitude point.
Fig. S52. Observed and calculated position of
meteorites on the ground, for an origin longitudeof 61.40ºE (=29.5 km altitude, triangle), 61.51ºE(=31.8 km altitude, upper dashed line) and61.23ºE (=26.1 km altitude, lower dashed line).
Black dots are single finds, open circles aregroup finds.

Table S15 lists the calculated andmeasured displacements along the trajectoryfor release at 29.7 km altitude. Size sorting
due to small fragments being more efficiently stopped than bigger ones by friction with theatmosphere resulted in a mass (m), in kg, falling on average at a longitude λ = 60.906 - 0.18883log10(m) - 0.0073 (log10(m))2, but a range of masses is found at each location (see below).
Comparing the mass-dependent behavior to the observed distribution of meteorites (Fig. S52),
calculated from the point that no further ablation occurred, shows that meteorites were mostly
broken into their final form between 31.8 km and 26.1 km (±0.6 km) altitude, in good agreementwith an episode of rapid fragmentation in our meteor model (Fig. S18C).

Chebarkul Lake Meteorites(contributions by: V. Grokhovsky and P. Jenniskens)
Shortly after the fall, a circular hole was found in Chebarkul Lake with a scattering of ice
fragments surrounding it (Fig. S53A). During investigation by Ural Federal University (UrFU)
researchers on February 17th, 51 small rocks were found scattered 5-50 m from the hole (Fig.
S53A, and #1 in Table S14). A police guard did not permit searches within 5 m of the hole.

Fig. S53A: Small meteorite fragments recovered by a UrFU research team from Chebarkul Lake near thehole in the ice layer, shown right in an airborne photograph taken by Eduard Kalinin from a Diamond C2
aircraft shortly after the hole's discovery on February 16th at 11:05:34 UT.

The position of the hole was measured at Lat. = 54.959377 ±0.0003ºN, Long. =60.322107±0.0005ºE at about 01:00 UT that day, by placing two people at opposite sides of thehole with the center of the hole on the viewing line, in two configurations forming a cross, andmeasure their position using a handheld GPS. The hole dimensions were estimated at a slightly
asymmetric ~7x8 m. The ice layer thickness was about 70 cm. Subsequent measurementssuggest that the GPS systems used that day were not well calibrated.
84

Many recovered meteorite fragments show fusion crust with strong curvature (Fig. S53A).
The abundance of fusion crust may be a selection effect, as darker rocks were easier to find, or it
may indicate that these fragments came from the surface of the impacting meteorite, which thenmust have been irregularly shaped by ablation.
At the time, the origin of these fragments was uncertain. Alternatively, they might have comefrom smaller meteorites that fragmented deep in the atmosphere and low enough to not cause
further fusion crust. In that case, however, fragments ought to have fallen over a wider area
along the trajectory, but no other such fragments were found.
Fig. S53B: Meteorite impact on Lake Chebarkul,
captured in video by Nikolaj Mel'nikov. From top tobottom: at 03:20:32.20 UT, the landscape is lit by thefireball;at

03:21:34.68

UT,

the

landscapeisunremarkable, reddish illuminated by the rising sun;one frame later, a cloud of ice or snow is detected (dotjust below the arrow); in later frames that cloud isobserved to be blown in the wind out of the frame to
the right. Video courtesy of Gennadiy Ionov.

The meteorite impact on the lake's icy cover
was captured on video by a 25 fps video security
camera owned by Nikolaj Mel'nikov in Chebarkul (Long. = 60.34461ºE, Lat. = 54.976852ºN).
The video shows that 62.52 seconds after the fireball lit up the landscape, a white spot emerged
suddenly from one frame to the next, in the direction where the hole in the lake was later found(Fig. S53B). Counting frames from the time of peak brightness, assumed to be at 3:20:32.2±0.1
UT (Sect. 1.1), the impact occurred at 03:21:34.72±0.1 UT. What is presumably a cloud of ice orsnow is seen to rise and expand in subsequent frames, creating a dark shadow in the landscapebehind. The cloud is then elongated by wind, which blows stronger higher above the ice. In thenext 7 minutes, the cloud drifts towards the right side of the frame, seen in projection against thedark forested shore in the background (Fig. S53B).
In an effort to locate a possible surviving meteorite, a team of the UrFU Quantum
Magnetometry Laboratory conducted a magnetometer survey of the site using a MMPOS-2

85

magnetometer-gradiometer and standard GPS navigator Garmin-60cx on February 28th andMarch 11th [98]. 6,000 points of the Earth magnetic field were measured in a grid separated by 1
m, covering an area of 60 x 100 meters around the hole (Fig. 53C). An anomaly was found at
Long. = 60.3206725ºE, Lat. = 54.9593669ºN, indicative of what may be an iron-containing
object, just South-East from the center of the hole at the time of the measurement [98]. The
absolute accuracy of that position was 15 meters. Subsequent dives only found depressions in the
mud at the bottom of the lake. The position of the hole was 98m further west than measured on
February 17, at Long. = 60.32058±0.00013ºE and Lat. = 54.95940±0.00013ºN (Fig. S53C).
Fig. S53C: Map of magnetic anomalies with aresolution of 1 nT [98]. The dashed circle marks
the position of the hole on March 11. The solid
black circle marks the suspected location of themeteorite. North is up, and the center of hole(affected by ice drift) is displaced by X = +20m
and Y = +25m.

A similar, but again slightly different,
location and a further hole diameter estimate
as well as sun illumination data were derived upon request from a calibrated satellite image (©
CNES 2013, Distribution Astrium Services /Spot Image S.A., France, all rights reserved) taken
at 50 cm/pixel resolution by the French Pléiades 1A satellite at 7:30:41.6 UTC on February 22.
The published picture can be found on the website: http://www.astrium-geo.com/en/4687russian-meteorite-impact-viewed-by-pleiades. The hole was viewed in a direction 10.3ºW and
32.1ºN, while the Sun elevation was 24.52º and azimuth 168.54º (SSE). Shadows of people
standing close to the hole are seen. The diameter and the center of the hole were measured fromthe calibrated full resolution satellite image data by Ulrich Johann, Astrium Satellites GmbH.
The values determined here are 6.3±0.5m, with Long. = 60.32087±0.00006ºE, Lat. = 54.95976±0.00006ºN with respect to the GPS reference frame WGS 84 geoid, respectively. This is 19m
east and 40m north of the magnetometer survey position. Drift in the ice sheet from winds andtides, or measurement errors, could account for these smaller differences.

86

At the time of writing, news came that the search of meteorite fragments in the lake based on
the magnetometer results was successful. The first probable meteorite fragment with a mass of
1.5 kg was recovered from the bottom of the lake by diver Alexey Lyahov in the morning of2013 September 24th. The main mass was recovered on October 16th and found to weigh ≥570
kg, part of which is shown in Fig. S53D. The impacting mass may have been 600-650 kg.

Fig. S53D: Main mass of the Chelyabinsk fall at the Chelyabinsk State Museum of Local History
shortly after recovery from Chebarkul Lake. Photo courtesy of Andrey Yarantsev.

Model of Chebarkul Lake Impact(Contributed by: G. Gisler)
In order to investigate whether the hole could indeed have been created by a falling meteorite, 2D dynamical simulations in axisymmetry were run to investigate the size of the expected hole ina 70-cm thick ice layer at -25 ºC ground temperature (-20ºC air temperature) for different sized
masses (spheres of 3.3 g/cm3) impacting the ice. The simulations were done with RAGE [99], afinite-volume adaptive-mesh hydrocode. Time steps of ~300 ns are required to resolve pressure
waves across the finest 0.25cm mesh size. The water depth used in the simulations was 7 m witha reflective bottom boundary. Three conditions were investigated: a 10 kg meteorite falling at the
expected 140 m/s (Table S15), a 100 kg meteorite falling at a high 600 m/s, and a 200 kg
meteorite falling at 1,300 m/s. In this initial investigation, vertical impact trajectories wereassumed (the calculated impact angles are 3º, 45º, and 47º from the vertical, respectively).
The 10 kg meteorite (Fig. S54A) punched through the ice intact, but did not carry enoughmomentum to create a water rebound powerful enough to increase the hole size to 6 meter87

diameter. The ice refroze rapidly. The 100 kg meteorite (Fig. S54B) just barely punched throughthe ice. The meteorite shattered and the remains smeared around the bottom of the crater. The
water was heated enough to not have frozen over at the end of the simulation.

Fig. S54: A 2-D model of meteorites falling on ice (yellow) covering the lake water (orange). Verticaland horizontal scales are in cm, while the color scale depicts density, ranging from 0.0 to 1.0 g/cm3 (blueto red). (A) 10 kg meteorite falling at 140 m/s; (B) A 100 kg meteorite falling at 600 m/s; (C) A 200 kg
meteorite falling at 1,300 m/s, plot now showing the second invariant of the deviatoric stress tensor in theice at 15 ms after contact, plotted in a linear scale ranging from 0 to 4.0 × 107 dyn/cm2; (D) A color
representation of the deviatoric stress tensor values in two dimensions as a slice through in the ice layer.
Color scale is logarithmic, ranging from 1.0 × 106 (blue) to 3.0 × 109 dyn/cm2 (red).

The 200 kg meteorite (Fig. S54C) impact shakes the ice out to at least 12 m from the impact site(edge of numerical grid), but these oscillations are insufficient to break the ice, which has atensile strength of 3 × 109 dyn/cm2. Because of the shaking, there is some cavitation occurring in
the water below. These low-density voids limit the time step of the calculations, which made thisa slow run. These pockets are small and ice breakup is not expected from these cavitations.
Instead, this would result in some pock marking of the ice layer's bottom surface. Hence,
inspection of the bottom ice surface may have revealed whether the impact energy was as high as
the value assumed here.
The calculations suggest that the ice is so thick and cold that it would prove a robust shieldpreventing fragments of under 100 kg getting through. On the other hand, a large enoughfragment (200-1,000 kg) could have made a hole in the ice.

88

4. Meteorite Characterization

4.1. Mechanical Properties(Contributed by: V. Grokhovsky, S. Gladkovsky, P. Jenniskens, and D. Sears)
Mechanical properties of the Chelyabinsk meteorite were determined at NASA Ames, using aSouthWark-Emery Tensil Machine to measure the load at which small, uncut meteorites
developed the first crack. Three meteorites broke at a load of 1.16 (C3), 1.11 (C4), and 0.49 kN(C5), respectively (Fig. S47). The effective surface area to which the pressure was applied wasmeasured by placing aluminum foil between meteorite and press. From the smallest area of theindent on the top and bottom of the meteorite (measured: 0.027, 0.034, and 0.012 cm2), thequasistatic compression strength is determined to be 330 MPa (C3: 4.46 g), 327 MPa (C4: 4.84g) and 408 MPa (C5: 1.58 g), similar to other ordinary chondrites [100]. The uncertainty ismostly that in the surface area, nominally ~20%, but perhaps as high as a factor of two.
At the Ural Federal University(UrFU),

compression

strengthmeasurements were made using theuniversal

servo-hydraulic

INSTRON

8801 tensil machine (grip displacement
0.5 mm/min) at room temperature. For
this measurement, the meteorite was cut
to have a squared area of approximately
10 × 10 mm and height 20 mm.
Similarly cut Tsarev (type L5) meteorite
Fig. S55: Optical image of Chelyabinsk C4, broken
along a shock vein that terminated at the fusion crust on
the left. The shock vein surface is warped like that of ashatter cone. Scale bar is in mm (main markers: cm).

samples [95] were used for comparison.
The minimum rupture load for Tsarev
samples

was

16.26

kN,

while

Chelyabinsk samples broke at 6.18 kN.
This translates to a compressive strength of 132.5 MPa for Tsarev and 64.0 MPa for
Chelyabinsk. Literature values for Tsarev [101-103] are in the range 150-500 MPa (medianvalue: 320 MPa). Hence, it is possible that this compression strength is underestimated by a89

factor of 2-3 in both cases. Alternatively, the Chelyabinsk sample measured at UrFU was weaker
than the Chelyabinsk meteorites measured at Ames due to fractures or other type of weakness
along shock veins.
Meteorite C4 developed a crack along one of the shock veins (Fig. S55). This is a potentially
important weakness in the structural strength of this particular ordinary chondrite that could havecontributed to the manner of fragmentation during descent. The exposed surface of the shockvein, photographed at the CheMin laboratory at NASA Ames Research Center (Fig. S55), shows
the same surface features as typically seen in shatter cones.
The melt in the cracks that underlay melt veins can act either to strengthen the material bywelding clasts together, or leave clasts only weakly consolidated. Veins in the Chelyabinsk
meteoroid were created by an impact event in space, probably the one that produced thebrecciated structure of mildly shocked lighter clasts and moderately shocked darker clasts [17].
Moderate shocks can fracture the rock. Strong shocks can cause the melting of metal andsulfides, which are then pressure-driven through the cracked meteorite, increasing its mechanicalstrength, the residual heat facilitating the process. This can make the material harder than theoriginal rock. In this case, however, the laboratory experiments suggest that the production of
cracks weakened the meteorite more than shock melting increased its strength. Indeed, bolide
observations show that there is no clear correlation between shock level (S1-S6) andfragmentation behavior in ordinary chondrite bolides [15].

4.2. X-ray Computed Tomography(Contributions by: D. J. Rowland, J. Friedrich, Q.-Z. Yin, N. W. Botto, and S. Roeske)
A 0.53g fragment of Chelyabinsk, C3-3-4, was imaged at the Center for Molecular and Genomic
Imaging at University of California (UC), Davis, for X-ray Computed Tomography (CT). X-ray
tomographic images were obtained on the Center’s MicroXCT-200 specimen CT scanner(Xradia Inc.). The CT scanner has a variable X-ray source capable of a voltage range of 20-90kV
with 1-8W of power. Samples were mounted on the scanners sample stage, which has submicronlevel of position adjustments. The sample was secured in place using a custom plastic holder
such that the samples did not come in contact with any adhesive material. Scan parameters were
adjusted based on the manufacturer's recommended guidelines. First, the source and detector

90

distances were adjusted based on sample size and the optimal field of view for the given regionof interest. Once the source and detector settings were established, the optimal X-ray filtration
was determined by selecting among one of 12 proprietary filters, in this case the Xradia LE5
filter was used. Following this procedure, the optimal voltage and power settings were
determined for optimal contrast (85kV and 8W (94microAmp)).

Fig. S56. X-ray CT imagery of Chelyabinsk, fragment C-3-3-4. (A) Surface shape model rendering of Xray CT data showing external structure of the stone with fusion crust. (B) Shows a volume rendering ofinternal components. The internal components were rendered in a blue-green color scale with a thresholdof 22000-65535 over the nominal full scale of 0-65535, thus making the surface and matrix materials
transparent for the solid object imaged. The green components are FeNi and FeS and the light blue
components are finely disseminated FeNi and FeSi grains intermingled with silicates. (C) Single slice
view of the interior (1 of 1155 X-ray CT slices in this view direction with a pixel size of 5.4618 micron).
(D) Full section of the X-ray CT image (one of 2600 scans with a pixel size of 5.4618 microns).

91

Table S16. X-ray CT imaging of Chelyabinsk (fragment C3-3-4). Sample mass, CT resolution, number ofimage stacks, measured volume, and computed density (g/cm3) are listed.

Scan	
  ID	
  
C3-­‐3-­‐4	
  

Mass	
  (g)	
  0.53277	  Resolution	  (µm/vxl)	
  5.4618	  Tiles	
   Volume	  (cm3)	
  1	
  0.16147	  Density	  (g/cm3)	
  
3.30	
  

Lab	
  
UCD-­‐CMGI	  A total of 2600 projections over 360 degrees were obtained with 8 seconds per projection.
The camera pixels were not binned and the source-detector configuration resulted in a voxel sizeof 5.4618 micron. The tomographic image was reconstructed with a center shift (0.355 pixels)
and beam hardening parameter value of 0.25 to obtain optimized images. A smoothing filter ofkernel size 0.7 was applied during reconstruction. Images were reconstructed into 16-bit values.
With a precisely computed volume of 0.16147 cm3 for the imaged fragment mass of 0.53277
gram, we obtain a bulk density of 3.30 g/cm3 for Chelyabinsk (Table S16). This bulk density is inreasonable agreement when compared with the Consolmagno et al. [16] data for LL chondrites,
which reports 3.22±0.22 g/cm3.
Fig. S56 shows the exterior surface model of Chelyabinsk (C3-3-4) as determined by X-ray
CT imaging (panel a), interior high atomic number (Z) elements shown in green (FeNi metal,
FeS) and blue (silicates intermingled with finely disseminated FeNi and FeS grains) (panel b) as
well as the slices of X-ray absorption maps (panels c, d). Fusion crust on the exterior, fracturesand void spaces, and chondritic texture in the interior with abundant chondrules, metal andsulfide grains are obvious. Full X-ray CT data and 3D rendition of the fragment C3-3-4 areavailable as part of the Supplementary Materials (Movie S1) and from the UC Davis website at
http://www.youtube.com/user/YinLabatUCDavis.
In addition to the 3D morphological description of chondritic components, we have used Xray CT data to precisely quantify the fraction of Fe metal (1.11 ± 0.13%) and FeS (troilite, 4.54 ±
0.54%) in Chelyabinsk (C3-3-4), following methodologies described by Friedrich [104, 105]. A
2D X-ray map of K-alpha lines from the electron microprobe results (Fig. S64 below) gives atroilite fraction of 4.6%. While the troilite fractions for H, L, and LL chondrites do not varysignificantly (Fig. S57A), the metal fractions vary significantly among the ordinary chondrite
groups (Fig. S57B). Chelyabinsk’s metal fraction of 1.11±0.13% is most consistent with those of
the average LL chondrite group [106].

92

Fig. S57. (A) Troilite (FeS) and (B) metal fractions in Chelyabinsk deduced from the X-ray CT data of C3-3-4. Data source for LL, L and H falls [106].

Fig. S58. Urey-Craig diagram [107] showing the position of Chelyabinsk relative to other majorchondrite groups of relative iron contents and oxidation states of the chondritic groups, where iron present
in metal and sulfide phases is plotted versus iron present in silicate and oxide phases, for bulk chondrite
composition. Red point represents 3D data obtained from the X-ray CT, blue point represents K-alphaline X-ray map from a 2D section by electron microprobe. Bias between the 2D and 3D approaches areapparent. The plot is adapted and modified after Brearley and Jones [108] and Krot et al. [109].

93

The estimated metal and sulfide fraction shown in Fig. S57, together with whole rock major
elemental composition of Fe and Si (see Section S4.5), allow the data to plot in the classic UreyCraig diagram [107-109] for chondrite classification to delineate their respective oxidation states.
As shown in Fig. S58, Chelyabinsk plots closest to the LL field.

Metal grain orientations(Contributed by: J. Friedrich)
Nearly all chondrites have experienced several episodes of impact-related processing andCheylabinsk is no exception. Cheylabinsk is a breccia consisting of at least two distinct light anddark lithologies. This brecciation is impact related: an impact into the Cheylabinsk parent bodybroke up the material and redeposited it. This material later experienced at least one significant
consolidating shock event, which produced the current S4 shock stage and petrofabric alignment
seen in the material.
Petrofabric investigations, including orientation and intensity of foliation, within the
Chelyabinsk C3-3-4 stone was accomplished by methods found in Friedrich et al. [104-105,
110]. In short, metal grains within tomographic volumes are digitally isolated and best-fit
ellipsoids are drawn around each. Orientation of the foliation can then be displayed by drawing aline through the long axis of each ellipsoid and collectively projecting points of intersection on ahypothetical sphere surrounding a sample on a stereoplot (Fig. S59).

Fig. S59. (A) Equal area, lower hemisphere stereoplot of major axis orientation of all individual metal
grains in the Chelyabinsk C3-3-4 stone. (B) Density distribution for the metal grain orientations. The
petrofabric is the result of a significant impact or compaction event on the Chelyabinsk (LL) parent bodysometime prior to atmospheric entry (see [105]).

94

Fig. S60. Degree of compaction or collective preferred orientation of metal grains (given by the Strength
Factor, C) versus shock stage in equilibrated ordinary chondrites.

Chelyabinsk has significant common orientation of metal grains indicating an extraordinary
impact-related petrofabric in the analyzed sample (Fig. S59B). To obtain a quantitative value forthe intensity of foliation, we used a variation of the orientation tensor method: the natural
logarithm of the ratio of major over minor eigenvalues of the ellipsoids are computed to yield astrength factor C [111,112]. The higher the strength factor, the greater the common orientation of
the metal grains in the sample and the greater the compaction/shock loading apparent in thematerial volume under investigation (Fig. S60). Strength of the petrofabric correlates well with
degree of shock loading and related compaction.
The Chelyabinsk C3-3-4 sample has an exceptionally well developed petrofabric, stronger
than those seen to date for ordinary chondrites of any shock stage (Fig. S60). Other data in Fig.
S60 include results from LL, L, and H chondrites [105, 110]. The petrofabric reflects the mostrecent extraterrestrial shock event experienced by the Chelyabinsk sample. The degree ofcompaction is consistent with the lack of intragranular porosity present in X-ray
microtomography volumes (Fig. S56 and [110]).

95

4.3. Magnetic Susceptibility and Paleomagnetic Signature(Contributed by K.L. Verosub, Q.-Z. Yin, and M. Sanborn)
Magnetic susceptibility was measured with a Bartington MS-2 magnetic susceptibility meterusing an MS-2B probe in the Department of Earth and Planetary Sciences at the UC Davis.
Sample 3-3-4 had a magnetic susceptibility value of log10χ = 4.49 (where χ is measured in unitsof 10-9 m3/kg). Values of log10χ for all LL type meteorites range from about 3.5 to 4.7 with LL5
meteorites falling in the slightly narrower range of 3.7 to 4.6 [27, 113]. Thus Sample 3-3-4 falls
at the upper end of the normal range for LL5 meteorites (Figure S61A).

Fig. S61. (A) Magnetic susceptibilities of Chelyabinsk (C3-3-4) compared to those of ordinary chondrite
groups [27,113]. (B) Alternating field demagnetization of natural remanent magnetization (NRM) of
sample C3-3-4. The intensity of magnetization is normalized by the initial intensity of magnetization,
which was 3.41 × 10-3 Am2/kg. (C) Acquisition of isothermal remanent magnetization (IRM) in d.c.
magnetic field. The intensity of magnetization is normalized by the final intensity of the IRM, which was
1.11 × 10-2 Am2/kg. (D) Alternating field demagnetization of isothermal remanent magnetization (IRM).
The intensity of magnetization is normalized by the intensity of magnetization achieved during theacquisition of the IRM.

96

Some other LL5 meteorites with high values of log10χ are Richmond (4.45), Aldsworth(4.54) and Paragould (4.54) [27,113]. Because LL5 meteorites have experienced some degreeof thermal metamorphism, it is unlikely that magnetite is the primary magnetic mineral andhence it is not possible to estimate the iron concentration from the magnetic susceptibility.
The magnetization of Sample 3-3-4 was measured with a 2-G Enterprises Model 755
automated cryogenic magnetometer in the Paleomagnetism Laboratory at UC Davis. The sample
responded well to progressive alternating field demagnetization of the natural remanent
magnetization (NRM). The initial intensity was 3.41 × 10-3 Am2/kg with a median destructive
field of 25 mT (Figure S61B). The initial (arbitrary) direction of magnetization was I = -36° D =314°, but during demagnetization the inclination moved smoothly to I = 43° while thedeclination remained unchanged, indicating the presence of two components of magnetization.
The sample was resistant to attempts to create a laboratory-induced anhysteretic remanent
magnetization (ARM). The ARM experiment was done twice, and in both cases, there was only amodest (factor of 2) increase in the intensity of magnetization and almost no change in themagnetic direction. When subjected to alternating field demagnetization, ARM reverted back to
the intensity observed at the end of the demagnetization of the NRM. This mode of behavior isunusual for terrestrial samples. One possible interpretation is that the thermal metamorphism thatthe sample experienced created an array of strongly-interacting magnetic grains. Studies of othermeteorites have also found various types of anomalous ARM behavior [114].
An attempt to induce an isothermal remanent magnetization (IRM) in the sample using
progressively higher d.c magnetic fields up to 1T was more successful. Most of the IRM was
acquired with applied fields between 20 and 75 mT (Figure S61C). The saturation IRM was 1.11
× 10-2 Am2/kg; the direction of the induced magnetization quickly became parallel to the appliedfield. Alternating field demagnetization of the IRM showed roughly the same behavior as
demagnetization of the NRM (Figure S61D).
In some instances, the NRM and IRM demagnetization behavior of a meteorite can be used
to estimate the magnetic field(s) in which the NRM was acquired. The basic principle of themethod, known as REMʹ′, is that one finds the demagnetization interval over which the
NRM/IRM ratio is constant [115]. That ratio times 3000 gives the magnetic field intensity inµT. For Sample 3-3-4, the NRM/IRM ratio is essentially constant at 0.38 over the97

demagnetization interval of 10 to 25 mT, which yields a magnetic field estimate of 1138 µT.
However, the demagnetization interval corresponds to the interval over which one of the twocomponents of the NRM was being removed, and hence may not be appropriate for the
REMʹ′ method. Over the demagnetization interval from 35 mT to 80 mT, the NRM/IRM ratio
ranges from 0.47 to 0.56 with a mean of 0.52, which yields a magnetic field estimate of 1545 µT.
Both of these estimates of the magnetic field are two orders of magnitude higher than magnetic
field estimates obtained from other meteorites using the REMʹ′ method. The most likely
explanation for this result is that the conditions of entry into the Earth’s atmosphere led toresetting of whatever previous remanent magnetization might have been present in the meteorite.

4.4. Petrography and Mineralogy(Contributions by: M. Zolensky, Q.-Z. Yin, S. Roeske, N. W. Botto, Loan Le, Daniel Ross)
Electron microprobe studies of Chelyabinsk C3 and C4 at NASA Johnson Space Flight Center
indicate that the petrography and mineral chemistry of Chelyabinsk is basically very similar towhat was already reported by Nazarov et al. [18]. The meteorite is a breccia of less-shocked
white clasts and moderately-shocked black clasts with abundant thin to cm-wide shock melt
veins. Chondrules exhibit clear boundaries in some instances and in others are significantly
recrystallized. Olivine exhibits mosaicism, planar deformation features, and local melting. Thereis no primary glass, having been devitrified to plagioclase (Ab79-85), which is partiallyisotropic.

Accessory phases include troilite, diopside, endiopside, chromite and kamacite.

Olivine and low-calcium pyroxene compositions average at Fa = 28.65 and Fs = 23.50, withpercent mean deviations of 0.54 and 4.70%, respectively. Olivine contains up to 0.05wt% CaO,
but is generally less than 0.02 wt%. These mineral compositional ranges are slightly larger thanthose reported by [18], but still compatible with a classification as LL5, shock stage S4 as
discussed in the next section [19].
The shock melt veins (Fig. S62) show metal layers located about 20 micron inside the vein,
but which follow the outer contours of the vein, shown as white in the BSE image of Fig. S62A,
and clearly in the Fe and Ni maps. Metal veins also project outward from the vein. It appears that
this layer is more Fe-rich, whereas the dispersed individual metal grains inside the vein are more
Ni rich (Fig. 62D and F).

98Fig. S62. A shock melt vein in Chelyabinsk. (A) Backscattered electron (BSE) image, (B) Si element
map, (C) Mg element map, (D) Fe element map, (E) Ca element map, (F) Ni element map.

Fig S63. Chelyabinsk C4 in optical light: comparison on a thin section in (A) plane polarized light, and(B) crossed polars. The shock-darkened lithology is indicated by arrows. The section measures 1.5 cm
across. (C) Light optical image of a polished surface, metal is white.

99

Figure S64. Three elements, false color composite images, arranged in red-green-blue sequence, for
Chelyabinsk polished section C3-3-4a.

100

Fig. S65. Backscattered electron (BSE) mosaic map of Chelyabinsk C3-3-4a, showing many chondrules,
including one bared olivine chondrule, metal and sulfide (troilite) grains, and fine grained matrix material.

The lower left 2/3 of the sample C4 is dominated by the white, less shocked lithology (Fig.
S63). The upper right 1/3 consists of dark gray shock melt materials with black, highly-shocked
pieces (Fig. 63C, arrowed).
At UC Davis, simultaneous elemental X-ray maps from the main characteristic peak (Kalpha) of major elements (O, Na, Mg, Al, Si, P, S, K, Ca, Ti, Cr, Mn, and Fe) (Fig. S64) and ahigh-resolution back-scattered electron (BSE) image (Fig. S65) were collected from a polishedthin section of Chelyabinsk C3-3-2, and C3-3-4a, respectively. A Cameca SX-100 was used, a 5spectrometer wavelength dispersive electron microscope, which is housed in the Department ofEarth and Planetary Sciences. The instrument settings were 15 keV, 80 nA current, 5 micronwide beam. The resulting stage scan is a merged file of numerous ~ 1600 micron wide cells, with
X-rays being recorded for 5 milliseconds every 4 microns as the stage moves. The false color
imagery records increasing intensity of X-ray counts for each element. A series of three elementscomposite images (in RGB, i.e. red-green-blue sequence) are shown in Fig. S64 to highlightelemental and mineral compositions.
BSE imagery combined with energy-dispersive spectrum (EDS) shows that the major silicate
phases in the sample are olivine, orthopyroxene, and plagioclase. The troilite (FeS) occurs bothas coarse crystals and as very fine (<3 micron across) grains aligned within pyroxene and olivine.
FeNi metal is variable in composition and locally contains minor Co. Minor phases include
chromite, ilmenite, apatite, and an FeZnS compound.
101

Table S17A. Chemical composition (Wt%) of olivine in a polished section of Chelyabinsk C3-3-2. Traceelements are listed with the detection limits.

Comment	
  

Mg	
  

Si	
  

olivine	  1	
  olivine	  2	
  olivine	  3	
  olivine	  6	
  olivine	  7	
  olivine	  8	
  olivine	  9	
  olivine	  10	
  olivine	  11	
  olivine	  12	
  21.19	
  21.57	
  21.33	
  21.51	
  21.49	
  21.39	
  21.47	
  21.42	
  21.47	
  21.39	
  17.49	
  17.63	
  17.44	
  17.55	
  17.55	
  17.49	
  17.49	
  17.35	
  17.45	
  17.49	
  

Ca	
  
(120	
  
ppm)	
  
0.011	
  0.015	
  0.025	
  0.038	
  0.015	
  0.029	
  0.016	
  0.007	
  0.013	
  0.013	
  

Mn	
  

Fe	
  

0.32	
  
0.36	
  
0.35	
  
0.35	
  
0.34	
  
0.33	
  
0.35	
  
0.35	
  
0.37	
  
0.37	
  

20.38	
  20.45	
  20.32	
  20.15	
  20.38	
  20.44	
  20.35	
  20.28	
  20.11	
  20.34	
  

Ni	
  
(525	
  
ppm)	
  
0.013	
  0.007	
  0.021	
  -­‐0.012	
  0.005	
  0.022	
  0.010	
  0.013	
  -­‐0.009	
  -­‐0.010	
  

Cr	
  	
  	
  
(170	
  
ppm)	
  
0.011	
  0.018	
  0.002	
  0.005	
  0.029	
  0.058	
  0.003	
  
0.227	
  0.027	
  0.008	  O	  Total	  	
  39.83	
  40.27	
  39.86	
  40.04	
  40.10	
  40.01	
  40.00	
  39.89	
  39.90	
  39.94	
  99.25	
  100.32	
  99.35	
  99.65	
  99.90	
  99.77	
  99.69	
  99.54	
  99.34	
  99.55	
  

	
  
	
  
	
  
	
  
	
  
	
  
	
  
	
  
	
  
	
  

Olivine composition was determined quantitatively by wavelength dispersive analysis.
Instrument set-up conditions were 15 keV, 30 nA current, 1 micron beam. Standards for the
major elements are as follows: Si, Mg: Olivine 174.1, from lherzolite nodule, Kamooloa stream
Kauai; Ni, Fe: synthetic olivine; Mn – Rhodonite. Ca – Cr-augite; Cr – Chromite. Ni is below thedetection limit on all points. The data are presented in Table S17, from which we calculate
average Fa = 29.2±0.3 for olivine (compared to Fa = 28.65 measured at NASA JSC). Fa ofolivine vs. Δ17O shows Chelyabinsk is an LL chondrite (Fig. 4D, main text).
Table S17B. Same in Wt% oxide.

Comment	
  olivine	  1	
  olivine	  2	
  olivine	  3	
  olivine	  6	
  olivine	  7	
  olivine	  8	
  olivine	  9	
  olivine	  10	
  olivine	  11	
  olivine	
  12	
  

MgO	
  
35.14	
  35.77	
  35.37	
  35.67	
  35.63	
  35.48	
  35.61	
  35.52	
  35.61	
  35.47	  CaO	
  0.015	
  0.021	
  0.035	
  0.054	
  0.021	
  0.041	
  0.022	
  0.010	
  0.019	
  0.018	  MnO	
  0.416	
  0.467	
  0.457	
  0.450	
  0.437	
  0.425	
  0.448	
  0.454	
  0.481	
  0.475	
  FeO	
  26.22	
  26.31	
  26.14	
  25.92	
  26.22	
  26.30	
  26.18	
  26.09	
  25.87	
  26.17	
  

102

NiO	
  
0.017	
  0.008	
  0.026	
  -­‐0.015	
  0.006	
  0.027	
  0.013	
  0.016	
  -­‐0.011	
  -­‐0.012	
  Cr2O3	
  0.017	
  0.027	
  0.002	
  0.007	
  0.042	
  0.085	
  0.004	
  0.332	
  0.039	
  0.011	
  SiO2	
  37.43	
  37.72	
  37.32	
  37.54	
  37.55	
  37.42	
  37.42	
  37.13	
  37.32	
  37.41	
  Total	
  99.25	
  100.32	
  99.35	
  99.65	
  99.90	
  99.77	
  99.69	
  99.54	
  99.34	
  99.55	  

Fig. S66. Back-scattered electron image of apatite grain in Chelyabinsk C3-3-2 polished section.

The Ca-P-Si composite map (Fig. S64F) shows the locations of phosphate. The larger ofthese regions of P concentration were selected for imaging to document shape and size of thephosphate grains (Fig. S66) as target materials for U-Pb isotopic dating (see Section 4.8). The
composition of the grains were confirmed with energy-dispersive spectrum (EDS), which show
all of the possible major and minor elements in one display acquired over 5-second timeintervals. Most that were imaged are Ca-phosphate with minor Mg. Some of the Ca-phosphate(assumed to be apatite) contains significant Cl (Cl-Apatite). Apatite, known to contain significant
amount of U and Th, are suitable for in-situ U-Pb dating to determine its absolute age andthermal history of the Chelyabinsk parent asteroid (see Section 4.8).

4.5. Major, Minor, and Trace Element Analyses(Contributed by: Q.-Z. Yin, J. Wimpenny, A. Yamakawa, and M. E. Sanborn)
Major, minor and trace element concentrations were determined using a high resolution magnetic
sector inductively coupled plasma mass spectrometer (Thermo Fisher Element XR ICP-MS) at
UC Davis. A sample slice (C3-3-1: 108.85 mg) was crushed by mortar and pestle to obtain ahomogenized powder. An aliquot of the whole rock powder (35.95 mg) was dissolved byconcentrated HF-HNO3 mixture in Teflon Parr bomb and heated in the oven at 200°C for 60
hours to ensure complete dissolution of all refractory phases. Once dissolved, small aliquots ofeach sample were taken, weighed using a 5-digit balance, and diluted to factors of ~ 5000 and
500,000 for trace and major element analyses respectively. All samples were diluted using 2%
twice distilled HNO3. An internal standard comprising In, Re and Bi was added to each sample at
a level of 10ppb in order to correct drift within each analytical session.

103

Samples were introduced to the Element XR using a dual cyclonic glass spray chamber and a
Teflon nebulizer with a flow rate of 50µl/min. The system was initially tuned for maximum
signal intensity using a 1 ppb solution of In, which gives a signal of ~1,000,000 cps at low
resolution. The Element XR has a range of resolving capabilities; low resolution (m/Δm ~400),
medium resolution (m/Δm ~4000) and high resolution (m/Δm ~10,000). Elements that haveinterferences at low resolution such as the transition elements and K can be analyzed using MR
or HR in order to avoid isobaric interferences. Prior to the analyses mass calibrations were
performed at each resolution, and the crossover threshold between counting, analogue andFaraday mode was also calibrated.
During each analytical session unknowns were calibrated using reference data for terrestrial
standards. Five standards were used with a range of chemical compositions; two basalts (BCR-2
and BHVO-2); two andesites (AGV-2 and JA-1) and one peridotite standard (JP-1). The
accuracy of our measurements were assessed by analyzing a series of well characterized
meteorite samples (Allende CV3, Murchison CM2, Orgueil CI1, Tagish Lake and Lance CO3)and comparing our measured values with published data. In general our measurements
reproduced published values for these meteorites to within ~5%. There are some exceptions tothis and larger uncertainties are associated with Na, K, Sn, Cs and W measurements. Certain
elements such as the PGE’s could not be successfully calibrated using the terrestrial standards
either because their concentrations in these standards are too low, or reference values are notwell known. Instead, we used Allende, Murchison, Orgueil and Tagish Lake to calibrate theseelements and treated Lance as an unknown to assess accuracy.
Table S18. Major, minor and trace element composition of the Chelyabinsk and other chondritic
meteorites
	
  	
  

Units	
   Chelyabinsk	
  

Li	
  

ppm	
  

Be	
  

Allende	
  Murchison	
  Tagish	  Lake	  	  Meas.	
  b,cRef. 	
  

	
  	
  

Meas.	
  Ref. 	
  

1.28	
  

1.20	
  

	
  

	
  	
  

	
  	
  

0.040	
  0.036	
   0.025	
   0.030	
  0.052	
  

	
  

	
  	
  

	
  	
  

11.50	
  

9.29	
  

9.58	
  

10.60	
  10.80	
  

	
  

1.13	
  

0.80	
  

0.85	
  

0.95	
  

0.99	
  

**	
  

1.31	
  

0.103	
  0.131	
   0.095	
   0.105	
  0.090	  	
  0.115	
   0.114	
  

1.29	
  

0.98	
  

0.92	
  

1.25	
  

0.98	
  

	
  

1.86	
  

1.64	
  

8.24	
  

8.20	
  

5.96	
  

5.90	
  

6.84	
  

7.20	
  

	
  

10.69	
  

9.36	
  

0.088	
   0.090	
   0.069	
  0.055	
  0.052	
   0.045	
   0.059	
  0.052	  	
  0.076	
   0.078	  Meas.	
  aMeas.	
  b,cRef. 	
  Ref. 	
  

1.60	
  

1.44	
  

1.89	
  

1.58	
  

ppm	
  

0.039	
  

Mg	
  

Wt%	
  

15.96	
  

Al	
  

Wt%	
  

1.18	
  

1.72	
  

1.09	
  

P	
  

Wt%	
  

0.153	
  0.104	
   0.100	
   0.113	
  

Ca	
  

Wt%	
  

1.70	
  

1.78	
  

1.86	
  

1.28	
  

Sc	
  

ppm	
  

9.54	
  

11.73	
   11.50	
  

Ti	
  

Wt%	
  

0.072	
  Orgueil	  Meas.	
  dRef. 	
  

1.50	
  

1.47	
  

1.47	
  

0.046	
   0.030	
   0.040	
  14.44	
   14.77	
   11.81	
  
1.70	
  

104

Lance	
  e

14.12	
   14.10	
  
1.42	
  

V	
  

ppm	
  

63.59	
  89.23	
   91.50	
   65.16	
  75.00	
  48.50	
   54.30	
   57.66	
  59.00	
  

	
  

Cr	
  

ppm	
  

3482	
  

3802	
  

3146	
  

3050	
  

2657	
  

2854	
  

2840	
  

	
  

	
  	
  

	
  	
  

Mn	
   Wt%	  0.300	
  

0.143	
   0.155	
   0.176	
  0.165	
  0.183	
   0.193	
   0.164	
  0.153	
  

	
  

0.17	
  

0.15	
  

Co	
  

ppm	
  

401.9	
  634.4	
   580.0	
   561.4	
  560.0	
  475.6	
   506.0	
   519.3	
  485.0	
  

	
  

	
  	
  

	
  	
  

Fe	
  

Wt%	
  

20.3	
  

22.6	
  

23.5	
  

21.0	
  

21.3	
  

18.4	
  

18.5	
  

19.7	
  

19.3	
  

**	
   25.40	
   24.37	
  

Ni	
  

Wt%	
  

1.17	
  

1.31	
  

1.270	
  

1.21	
  

1.230	
  

1.00	
  

1.080	
  

1.15	
  

1.110	
  

	
  

1.38	
  

1.40	
  

Cu	
  

ppm	
  

73.9	
  

113	
  

120	
  

133	
  

130	
  

133	
  

131	
  

125	
  

120	
  

	
  

	
  	
  

	
  	
  

Zn	
  

ppm	
  

49.9	
  

115	
  

113	
  

174	
  

180	
  

308	
  

312	
  

217	
  

207	
  

	
  

	
  	
  

	
  	
  

Ga	
  

ppm	
  

4.52	
  

5.77	
  

5.40	
  

7.56	
  

7.60	
  

9.55	
  

9.80	
  

7.97	
  

8.40	
  

	
  

	
  	
  

	
  	
  

As	
  

ppm	
  

2.17	
  

n/a	
  

1.9	
  

n/a	
  

1.8	
  

n/a	
  

1.85	
  

n/a	
  

1.74	
  

*	
  

1.79	
  

1.80	
  

Se	
  

ppm	
  

9.47	
  

n/a	
  

10.5	
  

n/a	
  

12	
  

n/a	
  

21	
  

n/a	
  

14.3	
  

*	
  

7.87	
  

7.50	
  

Rb	
  

ppm	
  

2.90	
  

1.25	
  

1.29	
  

1.64	
  

1.60	
  

2.37	
  

2.31	
  

1.80	
  

1.55	
  

	
  

	
  	
  

	
  	
  

Sr	
  

ppm	
  

10.56	
  15.93	
   14.70	
   10.07	
  10.00	
  

7.40	
  

7.81	
  

7.88	
  

8.30	
  

	
  

	
  	
  

	
  	
  

Y	
  	
  

ppm	
  

2.09	
  

2.94	
  

2.09	
  

2.00	
  

1.59	
  

1.53	
  

1.91	
  

2.13	
  

	
  

	
  	
  

	
  	
  

Nb	
  

ppm	
  

0.362	
  0.574	
   0.559	
   0.398	
  0.400	
  0.296	
   0.279	
   0.348	
  0.410	
  

	
  

	
  	
  

	
  	
  

Ru	
  

ppm	
  

0.696	
  

n/a	
  

n/a	
  

0.87	
  

n/a	
  

n/a	
  

1.08	
  

*	
  

1.01	
  

1.10	
  

3626	
  

3.20	
  
1.007	
  

2650	
  

0.655	
  79.04	
   89.00	
  

Sb	
  

ppm	
  

0.100	
  0.096	
   0.088	
   0.133	
  0.130	
  

0.169	
   0.130	
   0.172	
  0.170	
  

	
  

	
  	
  

	
  	
  

Ba	
  

ppm	
  

3.41	
  

n/a	
  

n/a	
  

3.10	
  

2.56	
  

2.98	
  

2.77	
  

*	
  

	
  	
  

	
  	
  

La	
  

ppm	
  

0.363	
  

0.512	
   0.510	
   0.315	
  0.320	
  0.258	
   0.246	
   0.341	
  0.310	
  

	
  

	
  	
  

	
  	
  

Ce	
  

ppm	
  

0.947	
  1.280	
   1.330	
   0.818	
  0.940	
  0.659	
   0.600	
   0.872	
  0.745	
  

	
  

	
  	
  

	
  	
  

4.00	
  

2.46	
  

Pr	
  

ppm	
  

0.140	
  0.198	
   0.210	
   0.120	
  0.137	
  0.098	
   0.091	
   0.125	
  0.114	
  

	
  

	
  	
  

	
  	
  

Nd	
  

ppm	
  

0.697	
  1.012	
   1.009	
   0.612	
  0.626	
  0.501	
   0.464	
   0.622	
  0.531	
  

	
  

	
  	
  

	
  	
  

Sm	
  

ppm	
  

0.231	
  0.325	
   0.328	
   0.193	
  

0.204	
  

0.169	
   0.152	
   0.203	
  0.185	
  

	
  

	
  	
  

	
  	
  

Eu	
  

ppm	
  

0.081	
  0.103	
   0.113	
   0.072	
  0.078	
  0.058	
   0.058	
   0.073	
  0.066	
  

	
  

	
  	
  

	
  	
  

Gd	
  

ppm	
  

0.285	
  0.399	
   0.409	
   0.251	
  0.290	
  

0.213	
   0.205	
   0.243	
  0.247	
  

	
  

	
  	
  

	
  	
  

Tb	
  

ppm	
  

0.058	
  0.075	
   0.081	
   0.050	
  0.051	
  0.041	
   0.038	
   0.049	
  0.048	
  

	
  

	
  	
  

	
  	
  

Dy	
  

ppm	
  

0.381	
  0.481	
   0.440	
   0.331	
  0.332	
  0.267	
   0.255	
   0.302	
  0.260	
  

	
  

	
  	
  

	
  	
  

Ho	
  

ppm	
  

0.083	
  0.096	
   0.113	
   0.068	
  0.077	
  0.054	
   0.057	
   0.067	
  0.066	
  

	
  

	
  	
  

	
  	
  

Er	
  

ppm	
  

0.242	
  0.294	
   0.300	
   0.213	
  

0.221	
  

0.167	
   0.163	
   0.201	
  0.188	
  

	
  

	
  	
  

	
  	
  

Tm	
  

ppm	
  

0.039	
  0.052	
   0.055	
   0.033	
  0.035	
  0.026	
   0.026	
   0.033	
  0.032	
  

	
  

	
  	
  

	
  	
  

Yb	
  

ppm	
  

0.258	
  0.308	
   0.300	
   0.223	
  0.215	
  

0.172	
   0.169	
   0.211	
  0.185	
  

	
  

	
  	
  

	
  	
  

Lu	
  

ppm	
  

0.040	
  0.043	
   0.049	
   0.032	
  0.033	
  0.027	
   0.025	
   0.031	
  0.033	
  

	
  

	
  	
  

	
  	
  

Hf	
  

ppm	
  

0.154	
  0.203	
   0.197	
   0.148	
  

0.180	
  0.106	
   0.106	
   0.135	
  0.134	
  

	
  

	
  	
  

	
  	
  

Ta	
  

ppm	
  

0.019	
  0.036	
   0.035	
   0.022	
  0.019	
  0.015	
   0.015	
   0.018	
  0.022	
  

	
  

	
  	
  

	
  	
  

Ir	
  

ppm	
  

0.417	
  

n/a	
  

n/a	
  

0.58	
  

n/a	
  

n/a	
  

0.547	
  

*	
  

Tl	
  

ppm	
  

0.002	
  0.054	
   0.053	
   0.081	
  0.092	
  0.116	
   0.142	
   0.109	
  0.090	
  

	
  

	
  	
  

	
  	
  

Pb	
  

ppm	
  

0.256	
  

1.28	
  

1.69	
  

1.60	
  

3.05	
  

2.40	
  

2.90	
  

	
  

	
  	
  

	
  	
  

Th	
  

ppm	
  

0.044	
  0.064	
   0.059	
   0.046	
  0.041	
  0.034	
   0.031	
   0.042	
  0.039	
  

	
  

	
  	
  

	
  	
  

U	
  

ppm	
  

0.014	
  0.017	
   0.015	
   0.012	
  0.012	
  0.009	
   0.008	
   0.011	
  0.009	
  

	
  	
  

	
  	
  

	
  	
  

0.684	
  1.26	
  0.435	
  2.63	
  0.663	
   0.720	
  Notes: Major, minor and trace element concentrations in Chelyabinsk, alongside measured values for
5 previously characterized ‘standard’ meteorites with published values for comparison. Reference
values have been taken from the following publications; aJarosewich et al. [116], bBrown et al. [117],

105

c

Friedrich et al. [118], dLodders [119], and eMetbase [120]. Element concentrations are calculated bycalibrating to a series of terrestrial standards; BCR-2, BHVO-2, AGV-2, JA-1 and JP-1. Elements
marked * have been calibrated using the meteorites Allende, Murchison, Orgueil and Tagish Lakeand consequently no concentration data can be provided for these meteorites. Accuracy of theseanalyses can be assessed by comparing our measured values with reference data for Lance. Elements
marked ** have also been calibrated using the meteorites Allende, Murchison, Orgueil and Tagish
Lake, however these meteorites were also separately measured as unknowns during the sample run
and the results of these analyses are presented in italics for comparison with reference data.

4.6. Ultrahigh Precision Cr Isotope Analysis(Contributed by: Q.-Z. Yin, , A. Yamakawa, and M. E. Sanborn)
A fragment of Chelyabinsk, C3-3, was sliced using a BUEHLER IsoMet Low Speed Saw andDiamond Wafering Blade. A sample slice (C3-3-1: 108.85 mg) was crushed using an agate
mortar and pestle to obtain a homogenized powder. An aliquot of the homogenized whole rockpowder (35.95 mg) was dissolved using concentrated HF-HNO3 in a 3:1 mixture in Parr aciddigestion vessel by heating in an oven at 200°C for 60 hours to ensure complete dissolution of allphases, including Cr-rich refractory phases such as spinel and chromite. The resulting clear
sample solution was evaporated, dissolved in 6 M HCl, heated at 90 °C overnight and evaporated
again. The sample was then re-dissolved in 6 M HCl and a 40 % aliquot of the dissolved sample
was taken for Cr isotope measurements.
Following a three step column chemistry as described in Yamakawa et al. [121], the Cr
isotope ratios were measured using ThermoFisher TRITON-Plus at the Department of Earth andPlanetary Sciences at UC Davis. The purified Cr fraction collected after the column chemistry
separation procedure was mixed with a silica gel-boric acid-Al type activator and loaded onto asingle outgassed W filament. The Cr fraction was split among four filaments with equal loading
amounts (i.e., 3 µg Cr per filament). Standard filaments, with Cr standard SRM 979, wereanalyzed both before and after the four filaments with the sample. The instrumental massfractionation effect was corrected according to an exponential law using a 50Cr/52Cr ratio =0.051859 [122]. Interferences on 50Cr and 54Cr from 50V and 54Fe, respectively, were correctedby monitoring 51V and 56Fe. The beam intensity of 52Cr was set at 1 × 10-10 A (± 15 %). A gain
calibration was performed before each analysis. Each filament measurement consisted of 48

106blocks of 25 cycles (8 s integration time per cycle) for a total of 1200 ratios per filament. A 60 s
baseline was measured and the amplifiers were rotated at the beginning of each block.
Table S19. Cr isotopic data of Chelyabinsk from this study. For comparison, the ε53Cr and ε54Cr data forother ordinary chondrites from literature [21,123] are also shown in this table.
ε53Cr

ε54Cr

Chelyabinsk

0.23 ± 0.03

-0.38 ± 0.08

Ste.-Marguerite (H4)0.13 ± 0.06

-0.39 ± 0.07

Knyahinya (L5)0.15 ± 0.06

-0.38 ± 0.08

Chainpur (LL3.4)

0.24 ± 0.06

-0.47 ± 0.07

Olivenza (LL5)

0.23 ± 0.06

no data

St-Séverin (LL6)

0.28 ± 0.06

-0.41 ± 0.10

ε53Cr and ε54Cr values of the sample were calculated relative to the Cr standards, defined as
ε53,54Cr = [(53,54Cr/52Cr)sample/(53,54Cr/52Cr)standard -1] × 104. Our result shows both ε53Cr and ε54Cr
values of Chelyabinsk are identical within error to those of other LL chondrites (Table S19 andFig. S67). ε54Cr values are becoming an increasingly useful tool to identify meteorite groups andprovenances (e.g. [21, 124]). Here we show that Chelyabinsk (ε54Cr = -0.38 ± 0.08) is identicalto those of other ordinary chondrites (~-0.4), suggesting that Chelyabinsk is derived from theprecursor material in the solar nebula where LL type ordinary chondrites formed.
Fig. S67. Variation of ε54Cr values among various
terrestrial and extraterrestrial materials. Our ε54Cr
data of Chelyabinsk is identical to those of reported
values for ordinary chondrites. Filled symbols
represent data acquired at University of California,
Davis (two data points for Sutter’s Mill are reported
in Jenniskens et al. [1]). The ε54Cr data of Earth and
Moon

are

represented

by

JP-1

and

70017,

respectively. Open symbols are literature data:
diamonds, inverted triangle and regular triangles
from Trinquier et al. [21], Qin et al. [125], andYamakawa et al. [126], respectively.

107

4.7. Oxygen Isotope Analyses(Contributed by: K. Ziegler, T. Nakamura, I. Ahn, J. I. Lee, Q.-Z. Yin, M. E. Sanborn, andA. Yamakawa)
Bulk oxygen isotope compositions of many ordinary chondrites are summarized and reported by
Clayton et al. [20]. The three ordinary chondrite groups have oxygen isotope compositions thatfall in similar ranges but are resolvable from each other. Thus, the measurement of oxygenisotope ratios is a useful tool to identify different ordinary chondrite groups.
Four Chelyabinsk meteorites, an 0.6 g sample C3-3 (Fig. S47) provided by Chelyabinsk State
University to the Consortium, TJI (~1g) acquired by Korea Polar Research Institute, andSamples 001 and 002 (~0.5 g) provided to the University of New Mexico, were gently crushedwith mortar and pestle. Fresh fragments of interior materials were selected under a stereoscopic
microscope to avoid any possible contamination from fusion crust. Oxygen isotope analyses
were performed using the CO2 laser-­‐based BrF5 fluorination system following procedures of Ahn
et al. [127] at the Korea Polar Research Institute (KOPRI), Korea, and following modified
procedures of Sharp [128] at the Institute of Meteoritics (IOM) at the University of New Mexicoin Albuquerque, U.S.A.
Table S20. Oxygen isotope compositions of Chelyabinsk bulk rock samples.*Stone

Mass (mg)δ17O’ (‰)

δ18O’ (‰)

Δ17O’ (‰)

Lithology

Laboratory

TJI

2.87

3.89 ± 0.01

5.05 ± 0.01

1.22 ± 0.01

light

KOPRI

TJI

1.85

3.84 ± 0.01

4.79 ± 0.01

1.31 ± 0.01

light

KOPRI

TJI

2.04

3.76 ± 0.01

4.69 ± 0.01

1.28 ± 0.01

light

KOPRI

001-A

1.0

3.62 ± 0.01

4.67 ± 0.01

1.15 ± 0.01

grey

IOM

002-A

1.1

3.77 ± 0.01

4.99 ± 0.01

1.14 ± 0.01

grey

IOM

002-B

1.4

3.73 ± 0.01

4.86 ± 0.01

1.17 ± 0.01

melt

IOM

C3-3-31.0

3.89 ± 0.03

5.03 ± 0.01

1.23 ± 0.03

greyishIOM

C3-3-3

1.2

3.53 ± 0.01

4.76 ± 0.01

1.02 ± 0.02

greyishIOM

C3-3-3

1.3

3.58 ± 0.02

4.58 ± 0.01

1.16 ± 0.02

greyishIOM

C3-3-31.8

3.67 ± 0.01

4.40 ± 0.01

1.13 ± 0.01

greyishIOM

C3-3-31.8

3.62 ± 0.01

4.63 ± 0.01

1.17 ± 0.01

greyishIOM*) The analytical uncertainty is the 1-standard-error obtained by 20 cycles of sample-standard comparisonin the mass spectrometer.

108

Oxygen isotopic ratios were calculated using the following procedure: the δ17,18O values referto the per-mil deviation of a sample's (17O/16O) and (18O/16O) ratios from the V-SMOW standard
values, expressed as δ17,18O = [(17,18O/16O)sample/(17,18O/16O)V-SMOW - 1] * 103. The delta-values
were then converted to linearized values by calculating: δ17,18O’ = ln[(δ17,18O + 103)/103] * 103 inorder to create a straight mass-fractionation line in the three oxygen isotope plot such as Fig. S68(A). The Δ17O’ values were obtained from the linear δ values by the following relationship:
Δ17O’ = δ17O’ – 0.528 * δ18O’. Δ17O’ values of zero define the terrestrial mass-fractionation line,
and Δ17O’ values deviating from zero indicate mass-independent isotope fractionation. Typicalanalytical precision of the laser-fluorination technique is better than ± 0.02‰ for Δ17O’.

Fig. S68. (A) Oxygen isotope diagram, plotting Chelyabinsk (red circles) and H, L and LL chondrites[20]. TFL refers to terrestrial fractionation line as defined above. CCAM refers to carbonaceous chondrite
anhydrous mineral line [129]; Y&R refers to a line defined by unaltered minerals from CAIs in Youngand Russell [130]. V-SMOW: Vienna standard mean ocean water. Note the different scales on x- and yaxis. (B) ε54Cr versus Δ17O’ in Chelyabinsk (red square), compared to the other major meteorite groups.
Data sources for Δ17O’ and ε54Cr data of chondrites and achondrites are from [1, 20-21, 129-134].

A total of eleven interior chips of Chelaybinsk were analysed (Table S20 and Fig. S68). The
TJI sample is from the light lithology. Samples 001-A and 002-A are from the light grey
coloured host chondrite with abundant relict chondrules and recrystallized matrix; it also
contains metal and sulfide, and is highly shocked and invaded with sulfide-rich impact melt
veins. Sample 002-B is dark grey/black impact melt material, consisting of a matrix that isquenched silicate melt, including finely disseminated sulfides. Abundant partly resorbed grains109derived from the chondrite host are entrained in this melt material. Sample C3-3-3 is from agreyish lithology with small spots of light lithology, and is from the same stone (C3-3) that was
analyzed for its Cr-isotopes in the previous section.
The results show that all eleven data fall in the oxygen 3-isotope space occupied by theequilibrated LL-group meteorites (≥ petrologic type 4) reported by Clayton et al. [20] (Fig. S68).
The Chelyabinsk mean value of 1.18 ± 0.02‰ (1 sigma standard deviation) for Δ17O also agrees
well with literature data of LL chondrites that range from 0.97‰ to 1.44‰ with a mean Δ17O =1.24 ± 0.13‰ [20].
These results indicate that Chelyabinsk is heterogeneous both on a large (different stones)
and a small (different C3-3-3 aliquots) scale in terms of oxygen isotopes. There are two possible
reasons for this variation: (1) the oxygen isotopes are not fully equilibrated in spite of thermal
metamorphism typical for LL5 meteorites, or (2) the oxygen isotopes are equilibrated, but themineral abundances of the eight 1-3 mg chips analyzed are not the same. The variation seen in
the Chelyabinsk data is common for ordinary L and LL chondrites with petrologic types 4 and 5.
4.8. U-Pb Age(Contributed by: Q-Z. Yin, Q. Zhou, X-H. Li, Q-L. Li, Y. Liu, and G.-Q. Tang)
Prior to in-situ U-Pb analyses, a thin section of the Chelyabinsk meteorite was imaged withJEOL JXA-8100 electron probe at the Institute of Geology and Geophysics, Chinese Academy of
Sciences (IGG-CAS) in Beijing. The electron microprobe was equipped with an energy
dispersive spectrometer (EDS) to identify phosphate grains and select suitable analytical spots,i.e., to avoid micro-fractures, inclusions and other observed physical defects in the individual
phosphate grains (Fig. S69). For more details see Section 4.4.
In-situ isotopic analysis of the U-Pb system was performed on a large radius magnetic sector
multi-collector Cameca IMS-1280 ion microprobe at the Institute of Geology and Geophysics,
Chinese Academy of Sciences (IGGCAS) in Beijing. Samples were carbon-coated prior to SIMS
analysis. The detailed analytical procedure for U-Pb dating of phosphate grains can be found in
Li et al. [135] and a brief introduction is given here. The O2- primary ion beam was accelerated
at -13kV, with an intensity ranging between 7 and 9 nA. The aperture illumination mode (Kohler
illumination) was used with a 200µm diameter aperture, resulting an ellipsoidal spot size of 20 ×
30 µm. Positive secondary ions were extracted with a 10 kV potential. A single ion-counting

110electron multiplier (EM) was used as the detection device to measure secondary ion beam
intensities of 204Pb+, 206Pb+, 207Pb+, 208Pb+, 232Th+, 238U+, 232Th16O+, 238U16O+, 238U16O2+ and amatrix reference peak of 40Ca231P16O3+ at a mass resolution of ~9,000 (defined at 50% height).
The 40Ca231P16O3+ signal was used as reference peak for tuning the secondary ions, energy andmass adjustments.

Fig. S69. Apatite grains found in Chelyabinsk (section C3-3-2). Ovals indicate analyzed spots by Cameca
IMS-1280. Numbers indicate the corresponding data in Table S21.

Fig. S70. U-Pb Concordia plot for Chelyabinsk apatite grains (Table S21). The upper intercept age is4,452±21 Ma with a mean-square weighted deviates (MSWD)=1.4.

111

Pb/U ratios (Fig. S70) were calibrated with power law relationship between Pb/U and UO2/U
relative to an apatite standard of NW-1 (1,160 Ma) that comes from the same complex of Prairie
Lake as that of the Sano et al. [136] apatite standard (PRAP). U concentration is calibrated
relative to the Durango apatite which has U ~9 ppm [137]. The standard deviation of themeasured 206Pb/238U ratios in the standard was propagated into the unknown samples, in this case
the Chelyabinsk sample. Each measurement consisted of 10 cycles, with the total analytical timeof about 12 minutes. Correction for common Pb was made by measuring the amount of 204Pb andthe CDT Pb isotopic compositions [138]. The uncertainties for individual analyses are reported
as 1σ. The weighted average of 206Pb*/238U and Pb-Pb ages, quoted at the 95% confidence level,
was calculated using ISOPLOT 3.0 [139].
Table S21. SIMS U-Pb isotopic data of apatite from Chelyabinsk.
Spot

U
(ppm)

Th
(ppm)

207

Th/U

Pb* ±1σ/ Pb* (%)
206

207

Pb*
/ U
235

±1σ
(%)

206

Pb*
/238U

±1σ
(%)

t207/206(Ma)±1σt207/235(Ma)±1σt206/238
(Ma)

±1σ

1
5.4
5.6
1.03 0.5795 1.79
67.1
4.7
0.840 4.34 4457
26
4286
32
3930
77
2
6.9
6.9
1.00 0.5459 2.42
66.7
4.1
0.887 3.29 4370
35
4281
33
4092
65
3
5.6
4.6
0.82 0.5609 1.78
67.2
4.0
0.869 3.57 4410
26
4288
29
4033
68
4
6.2
5.2
0.84 0.5965 2.29
87.4
4.1
1.063 3.37 4499
33
4551
37
4669
92
5
7.0
9.0
1.29 0.5871 1.94
78.1
4.4
0.964 3.95 4476
28
4438
30
4353
71
6
5.6
4.5
0.81 0.5570 2.11
76.4
5.0
0.995 4.53 4400
30
4416
30
4453
66
7
4.4
3.2
0.73 0.5877 2.48
86.7
4.7
1.070 3.99 4478
36
4542
35
4689
77
9
4.7
5.6
1.21 0.5948 2.39
97.6
7.6
1.190 7.25 4495
34
4662
34
5053
79
10
3.9
3.2
0.83 0.5625 2.38
73.1
5.4
0.942 4.88 4414
34
4372
32
4280
64
11
5.2
4.9
0.95 0.5747 1.76
87.6
5.1
1.106 4.82 4445
25
4553
39
4800
114
13
6.7
6.5
0.97 0.5660 3.68
55.3
5.8
0.708 4.54 4423
53
4092
42
3452
52
14
7.2
7.2
1.00 0.5789 2.24
56.1
5.7
0.703 5.26 4456
32
4107
30
3432
51
15
8.3
7.9
0.94 0.5758 1.80
66.0
3.7
0.831 3.21 4448
26
4269
27
3900
59
16
1.7
2.3
1.35 0.5589 4.97
77.4
9.8
1.005 8.45 4405
71
4429
55
4484
63
17
7.6
10.1
1.32 0.5909 2.00
71.9
4.5
0.883 4.01 4486
29
4355
28
4079
59
* denotes radiogenic, using the modern terrestrial Pb as common-lead compositions (206Pb/204Pb =18.703, 207Pb/206Pb = 0.836,
Stacey and Kramers, 1975);

To test and verify the reliability of the developed phosphate dating technique, two additional
meteorites, a primitive achondrite Acapulco obtained from Dr. K. Marti and angrite NWA 4590
provided by Dr. Y. Amelin, were also selected for this study as both have precisely known
phosphate U-Pb ages by TIMS [23, 140]. Both meteorites are from very fast cooled parent
bodies with no sign of resetting [23, 140], ideal for precise age dating.
Seventy-three measurements of Pb-Pb isotope composition were obtained on apatite grains in
Acapulco. The weighted mean of 207Pb/206Pb ratios is 0.620 ± 0.002, translating to a Pb-Pb age of112

4,555.4 ± 5.2 Ma (uncertainties are reported at 95% confidence level, with a student t-factor
applied for the number of repeat analyses), assuming a primordial Pb composition for the initialPb [138]. The results from our study are consistent with the TIMS results (4,556.5 ± 1.3 Ma,[23]).
Eighteen Pb-Pb isotope measurements were obtained on silico-apatite grains [140,141] andone on a merrillite grain in angrite NWA 4590. There is no significant difference between theage of silico-apatite and merrillite. The weighted mean of 207Pb/206Pb for silico-apatite andmerrillite is 0.620 ± 0.002, translating to a Pb-Pb age of 4,556.6 ± 4.6 Ma (uncertainties arereported at 95% confidence level). The common lead of the phosphate in this sample isextremely low and 204Pb/206Pb ratio is nearly zero. The results from our study are consistent with
the TIMS result (4,557.381 ± 0.066 Ma [140]).
After these vigorous tests of our methodology, exactly 17 apatite spots were analyzed fromthe Chelyabinsk section C3-3-2 for U-Pb isotope composition. The results are listed in Table
S21, and the data are plotted in the classic Wetherill type U-Pb Concordia diagram (Fig. S70).
The upper intercept age of Chelyabinsk apatite is found to be 4452±21 Ma, using ISOPLOT 3.0[139]. There are a few smaller merrillite grains, however, the U contents were found to be too
low to yield useful data. Results from individual spot measurements for Chelyabinsk apatites are
summarized in Fig. S70.
The upper intercept age of 4,452±21 Ma is much younger than phosphate ages from otherordinary chondrites phosphate ages dated by conventional TIMS methods [22,23,142]. We notethat no ordinary chondrites, including H, L and LL chondrites reported by these workers, haveapatite U-Pb ages younger than 4.51 Ga. The only exception, to our knowledge, is a recent workby Tereda and Bischoff [24] who reported a Pb-Pb isochron age of 4.48±0.12 Ga Pb-Pb forphosphate in a granite-like fragment found in a LL3-6 ordinary chondrite regolith breccia AdzhiBogdo. This was performed using the SHRIMP ion probe technique, a similar SIMS technique tothat used here for Chelyabinsk. We have no reason to believe the SIMS and TIMS techniquewould provide a systematic bias in the U-Pb ages. Our results suggest that the
Chelyabinsk parent body must have experienced a significant thermal and/or collision resetting
event 115±21 Ma after formation of the oldest Calcium Aluminum rich inclusions in meteorites[25]. This may indicate a prolonged thermal cooling history of the Chelyabinsk parent body or,113perhaps more likely, a more recent impact related disturbance on the LL parent body in adifferent area than sampled by most other LL ordinary chondrites.

4.9. Reflection Spectroscopy(Contributed by: T. Hiroi)
Figure S71 shows the bidirectional visible-Near IR and biconical FT-IR reflectance spectra
measured at the Reflectance Experiment Laboratory at Brown University. Spectra are shown for
the exposed interior surfaces of two chips of C3 (a light lithology) and the shock darkened C6[143]. From these same samples, powders of grain size < 125 µm were prepared after removing asurface layer. The resulting material looked fresh, but did show stronger atmospheric waterbands due to a damper environment in the spectrograph. Those residual bands were removed.

Fig. S71. Reflection spectra of powder (thick line) and exposed surfaces (thin line) measured over the 0.3
to 2.5 µm wavelength range (left) and the 0.3 to 25 µm range (right), for both light (C3, top two curves)and dark lithologies (C6, bottom two curves) of the Chelyabinsk meteorite. In color are shown thereflectance spectra of light and dark lithologies on Itokawa [144].

Fig. S72 shows the continuum-removed natural log spectral plot of the C3-1 powder sample,
compared to powder samples of representative ordinary chondrites of H, L, and LL type. The
chip shows a similar band shape, but not shown here as the comparison spectra are for powder
samples. In detail, the light chip (C3-1) has a 0.8-1.2 micron reflectance shaped like that of H

114

chondrites, not LL chondrites. It is possible that this represents heterogeneity in the sample, C3-1
being richer in pyroxene than the bulk rock Chelyabinsk. The reflectance spectrum over thiswavelength range is mostly dependent on the olivine/pyroxene ratio of this particular specimen.
In detail, the band shape also depends on the Fe/Mg ratio and crystal size.

Fig. S72. Continuum-removed natural log spectral plot of C3-1 powder sample, compared to powder
samples of typical H (green), L (blue) and LL (red) chondrites.

The optical spectrum of the darker (C6) chip is mostly featureless (Fig. S71), with a bit ofterrestrial weathering at 0.5 microns. However, the 3-micron hydration bands are not strong, sothese surfaces are relatively fresh.
The resulting spectrum for the pre-atmospheric body would depend on how those light anddark components are mixed. If they are occur in separate components like boulders or gravels,and no intimate mixing occurs, then the asteroid spectrum would be nearly a simple linear
combination of those two. If fine grain regolith mixing occurs, then the dark component tends toaffect the whole spectrum significantly, which can make the absorption bands shallower and thealbedo lower. If the dark material is low in abundance, a Q-type spectrum can be the outcome,which can space-weather into an S-type spectrum. Even when the dark component is abundant,
space weathering can make the whole spectrum redder, and the cause of weak absorption bands
can be indistinguishable between dark matter mixing and space weathering.

115

Results are compared to in-situ measured reflectance spectra of the light and dark lthologies
of Itokawa in Fig. S71. Itokawa had black boulders as isolated rocks as well as lower-albedo
areas of regolith [144]. The near-infrared spectrometer (NIRS) onboard Hayabusa did not haveenough spatial resolution to measure spectra of individual boulders, and thus the "dark" lithology
spectrum in Fig. S71 is likely a combination of spectra of light and dark materials. The "dark"
Itokawa spectrum may result from the "light" Itokawa spectrum adding linearly a small fractionof dark Chelyabinsk component.

4.10. Thermoluminescence(Contributed by: D. Sears, I. A. Weinstein, A. S. Vokhmintsev, A. V. Ishchenko, andV. I. Grokhovsky)
Fragments of several Chelyabinsk meteorites were analyzed for thermoluminescence at the Ural
Federal University. Samples consisted of slices of 1 mm thickness (Fig. S73A) and powders
prepared by separating the core of some fragments from the fusion crust and then crushing thismaterial into a ~100 µm grain size powder, which was treated in hydrochloric acid to remove
metal particles (Fig. S73B).

Fig. S73. Chelyabinsk meteorite slices and powder.

116

Measurements were carried out in phosphorescence mode using a LS55 Perkin Elmer
spectrometer. A specially designed small heating appliance was used to measure thethermoluminescence (TL). The glow curves of the natural TL were registered at 440 nm
wavelength over the range from room temperature to 873 K at a linear heating rate of r = 2 K/s.
The natural TL spectra were measured at r = 1 K/s over the 300 - 650 nm wavelength range,
scanned at 700 nm/min. The temperature of the sample varied by ~30 K during one scan.
Table S22. Spectral parameters of luminescence in Chelyabinsk meteorite
TechniqueSampleT, K
437

slice C3
TL

481
powder P

393

powder P

300

slice C5300

PLComponent
G1
G2
G1
G2
G1
G2
G1
G2
G3
G4
G5
G6
G1
G2
G3
G4

Emax,
± 0.05 eV
2.74
2.40
2.82
2.43
2.81
2.43
2.77
2.45
6.28
5.42
5.17
4.84
2.80
2.45
6.23
5.39

FWHM,
± 0.05 eV
0.73
0.35
0.73
0.38
0.68
0.40
0.69
0.41
0.96
0.21
0.40
0.70
0.70
0.37
0.92
0.18

R2
0.996
0.993
0.995

0.999

0.999

Photoluminescence (PL) spectra were measured at room temperature, and scanned at a rate of
60 nm/min. Excitation spectra were recorded the sample excited at 440 nm, and measured at 200- 360 nm, while the emission spectra were recorded for 200 nm excitation over the wavelength
range of 300 - 650 nm.
TL spectra for samples C3 (Slice and Powder) are shown in Fig. S74A and S74B, peaking at
T = 437 and 393 K, respectively. The band profiles were decomposed by superposition of two
Gaussian shapes (satisfactory to R2 > 0.993) and the maximum energy (Emax) and Full-Width-atHalf-Maximum (FWHM) of each component are listed in Table S22. The stronger band (G1) is
2-4 times higher than the weaker (G2).
The natural TL (Fig. S75) has a peak in the 400 - 520 K range, with a high-temperature
shoulder at 520-750 K. These ranges are similar in shape and position to Dhajala's main TL peak117

[145]. The Dhajala meteorite is commonly used as a normalization standard for induced TL
measurements because it lies in the middle of the log-normal range for ordinary chondrites.
The intensity varies by a factor of 10 and the maximum temperature (Tmax) of the TL
peak from 427 to 487 K (Table S22) for different samples. This can be due to inhomogeneousmineral phases or mineral compositions, or differences in irradiation doses in space [29].

Fig. S74A. The natural TL spectra for the C3 slice measured at different temperatures (a) andapproximation by independent Gaussian components for T = 437 K (b)Fig. S74B. The natural TL spectra for the C3 powder sample measured at different temperatures (a) andapproximation by independent Gaussian components for T = 393 K (b)For a quantitative interpretation, the experimental curves of the 300-500 K range were
described in terms of a general-order kinetics equation [146]:,

118(Eq. S7)

where EA – activation energy, eV; r – linear heating rate, K/s; k – Boltzmann constant, eV/K; n0– initial concentration of occupied traps, cm-3; s˝ – effective frequency factor, s-1; b – kinetic
order, b > 1; T0 – initial temperature, K. The values obtained for activation energy and frequency
factor (Table S23) agree with those obtained by Biswas et al. [145].

Fig. S75. The natural TL measured in the 440 nm band (2.82 eV) for the samples of Chelyabinsk
meteorite (a) and approximation of the TL curves in terms of general order kinetics (b).

Fig. S76. The experimental excitation and emission PL spectra measured at room temperature for C5
powder and C5 slice (a) and spectra deconvolution into independent Gaussian components for C5 powder
sample (b).

Biwas et al. [145] also found that the kinetics order varies between b = 2 - 3, indicating thatcharge carrier traps of different types may be active at the temperatures under study. This could
mean that there are up to eight overlapping TL components so that a full theoretical analysis of
the glow curve structure would require independent input of the kinetic parameters (activation

119

energy, Arrhenius factor, etc.) for each peak. Because of that, empirical methods are normallyused to interpret induced TL data.
Table S23. Calculated TL kinetic parameters: Tmax is temperature of maximum thermoluminescense, EA
is activation energy barrier in eV, s" is effective frequency factor, b is kinetic order, and R2 is thecorrelation coefficient describing the accuracy of the fit [146].

Sample
C1
C2
C4
C5
P

Tmax,
±2K
487
487
467
444
427

EA,
± 0.06 eV
1.18
1.23
0.97
1.05
0.83

sʺ″,
s-1
1.7⋅1011
5.4⋅1011
2.8⋅1091.0⋅1011
5.6⋅108

b,
± 0.3
2.7
2.9
2.3
1.9
2.7

R2
−
0.999
0.999
−
−

Figs. S76 show the emission and excitation spectra for the most PL active meteorite C5 andits powder. Again, the spectral dependences are a superposition of several independent Gaussiancomponents, parameters of which are listed in Table S22. With varying energy, the shape of the
PL peaks do not change while their intensity decreases with varying energy of excitation in therange 6.2 to 4.5 eV. The similar values for the two Gaussian components suggests that the PL
and TL processes are due to similar recombination centers. The excitation spectra of the powder
sample show two extra bands (G5 and G6 in Table S22), alongside the dominant G3 and lessintensive G4 band that are typical for all studied samples.
At NASA Ames Research Center, two internal
chips of light lithology taken 2-3 mm from thecrust of sample C3 (left of line in Fig. S77) had astrongnaturalTL

signalsuggestingthat

temperatures ~200ºC did not penetrate that far into
the meteorite and that the temperature gradient of
this 1 cm meteorite were extremely steep.
Consistent with this, the fusion crust is extremely
thin (~0.2 mm). The average natural TL level,

Fig. S77. Chelyabinsk C3 fragment forcalculated in the way described by Sears et al.

thermoluminescence. Scale is in mm.

120

[147], is 47+/-13 krad. This corresponds to an orbit with a perihelion of 0.6-0.8 AU, using thearguments and curves of Sears et al. [148] to relate natural TL to perihelion (Fig. S78). This isconsistent with the estimates made on the basis of observed trajectory (Table S5B) and with
exposure ages (SOM Sect. 4.12) and dynamic ages (Table S6) indicating that the natural TL
levels were at their equilibrium at the time of fall. The TL properties of the dark vein material
were not determined, but they might have resembled the shock blackened ordinary chondrites
reported by Haq et al. [149].
The two chips had induced TL properties (TL sensitivity, TL peak temperature, and TL peakwidth) in reasonable agreement and the temperature and width are consistent with values
expected for equilibrated ordinary chondrites [150].
The TL sensitivity (the level of TL induced by a standard laboratory test dose normalized to a
standard meteorite, Dhajala) is 1.05+/-0.35. There is ambiguity in the significance of thisnumber which is easily removed when it is realized that this is a shocked meteorite (scale S4 on
the scheme described by Stöffler et al. [19]. If it was not shocked, the TL sensitivity of
Chelyabinsk would suggest that it was a petrographic type 3.8 or 4 on the metamorphism scale
described by Van Schmus and Wood [150] and Sears et al. [151]. This is inconsistent with thepetrographic type assigned on the basis of mineral composition and petrography.

Fig. S78. Natural TL levels for observed ordinary chondrites falls from Benoit et al. [153] with theperihelia distances suggested by Sears et al. [148] and with the data for Chelyabinsk indicated.

Figure S79 shows the Thermoluminescence sensitivity (TL induced by a standard laboratory
radiation dose normalized to a standard meteorite, Dhajala) as a function of petrographic type121

(i.e., degree of metamorphism on the parent body). The figure is from Sears et al. [152] with data
for Chelyabinsk superimposed with uncertainties reflected by the grey area. Using the TL
sensitivity, petroraphic type 3 has been subdivided into types 3.0 to 3.9 where the threemeteorites clustered around Dhalaja are type 3.8. On this basis, Chelyabinsk appears to be type
3.8 but this would be inconsistent with petrographic data (Sect. 4.4) that assigns it topetrographic type 5.
The TL sensitivity of Chelyabinsk compared with the TL sensitivity shocked ordinarychondrites suggests that the low TL sensitivity relative to types 5 and 6 is due to the meteorite
having experienced shock metamorphism to the level of S4 (30-35 GPa) (Fig. S80). Shock tolevels of S5 - S6 result in the complete destruction of feldspar, the mineral phase responsible forthe thermoluminescence signal, which would reduce the TL sensitivity to levels of ~0.01 or
lower [154].

Fig. S80. Diagram from [149] showing the
TL sensitivity of shocked meteorites as afunction of 40Ar content. Stepwise heating
experiments shows that 40Ar is lost at thetemperatures indicated and this has beenFig. S79. TL induced by a standard

related to shock class using data in [19].

laboratory radiation dose, normalized to a

These data are consistent with a shock

standard meteorite (Dhajala), as a function

classification of S4.

of petrographic type.

122

4.11. Electrospray Ionization Ultra-High Resolution Mass Spectrometry(Contributed by: P. Schmitt-Kopplin and N. Hertkorn)
The samples were surrounded by dense snow when found. After recovery, they were wrapped inporous paper to remove water. After drying, the samples were placed in plastic bags and stored atroom temperature. No further actions to prevent terrestrial organic contamination were taken.

Fig. S81. (A) Negative ESI-ICR-FT/MS mass spectra in the range m/z 150 to m/z 1,200 of the chondritic
methanol extract. (B) section of nominal mass 319 with corresponding assigned elemental compositionsof mass peaks as singly charged negative ions.

Two samples were analyzed at Helmholtz Zentrum München, a 3.6 g whole rock withcomplete fusion crust and a pea-sized 2.8 g impact melt sample (Fig. S49D,E). They were cut in
two with a diamond wire saw under minimal water cooling using water of Liquid
Chromatography / Mass Spectroscopy (LC/MS) analytical grade, in order to qualitatively
examine the interior of the sample and to choose the parts to be analyzed. One half of therespective samples are shown in Fig. S49D-E. The other half pieces were immediately crushed inan agate pillar, to avoid terrestrial contamination, and fragments from the core were isolated forfurther analysis.

123

An 80 mg fragment was selected and washed with methanol (500 µl LC/MS grade) prior ofbeing further crushed in the agate pillar. Methanol, a polar protic solvent was shown previously
to extract the maximum chemical diversity of polar compounds from organic chondrites asdetected by Electrospray Ionization Mass Spectrometry (ESI-MS [30, 155]). The slurry wastransferred into a 2 mL Eppendorf vial that was subjected to sonication for 60 seconds at room
temperature and directly centrifuged. The supernatant was injected into the Ion Cyclotron
Resonance Fourier-Transform (ICR/FT) mass spectrometer without further treatment.
Mass spectra were acquired using a Bruker SOLARIX 12 Tesla ion cyclotron resonanceFourier transform mass spectrometer. Singly charged and unfragmented negative ions weregenerated at atmospheric pressure within an Apollo II electrospray ionization (ESI) source at aflow rate of 2 µL min-1. Detailed information about the Electronspray Ionization Ion Cyclotron
Resonance Fourier-Transform Mass Spectroscopy (ESI-ICR-FT/MS) method applied in thisstudy for complex materials is given elsewhere [30]. Negative Electrospray Ionization (negative
ESI) was performed under conditions described earlier [155]; 3,000 scans were accumulatedwith 4 million data points resulting in more than 18,000 resolved mass peaks ranging from mass
150 to 700. The instrument´s performance was controlled by means of internal calibration on
arginine clusters prior to any analysis. The average errors in mass values relative to internal
standards (fatty acids) were usually < 100 ppb across a range of 150 < m/z < 1,500. The average
mass resolution ranged near 400,000 at nominal mass 400. The same internal calibrants wereused as in a previous study [30], resulting in a common absolute mass accuracy of 0.1 ppm. The
conversion of the exact masses into elemental compositions was shown in Tziotis et al. [156].
Basically, the molecular formula calculations based on excellent mass accuracy and mass
resolution were validated by network-based mass difference analysis from all initially assigned
compositions, with up to 5 elements (CHNOS) and isotopes as follows: 1H, 12C, 16O, 14N, 32S; the13

C and 34S isotopomers were included to validate the assigned molecular formulas with a

precision of 0.15 ppm.
The ultrahigh resolution mass spectra showed a wealth of organic compounds (Fig. S81). Outof 18,000 mass signals in the chondritic sample extracts within the mass range m/z 150 to 700,
2,536 elemental compositions could be assigned with the elements C, H, N, O, S (involving
isotopologues of 13C and 34S), of which 1,102 were identified as CHO compounds (shown inblue in the van Krevelen diagrams in Fig. S82A and S82B, 899 were identified as CHOS

124

compounds (shown in green), 391 were found CHNO compounds (orange), and 144 compounds
contained both sulfur and nitrogen (CHNOS; red). The impact melt solvent extract showedalmost identical counts of elemental formulas but with a shift in compositions towards higher
molecular mass, a relatively larger proportion of released nitrogen and aromatic compounds. The
van Krevelen diagrams (Fig. S82A,B) readily showed the rich chemical diversity as a projectionof the H/C versus O/C elemental ratios derived from all assigned elemental compositions,whereas the H/C versus mass diagram (Fig. S82C,D) allowed visualizing many chemical
homologous molecular series. In both diagrams, the size of the symbols was proportional to peakintensities, providing relative abundances of ions and a proxy of formation rate and stability of
the respective ions.

Fig. S82. van Krevelen diagram (H/C versus O/C elemental ratio) and H/C versus m/z plots of thenegative ESI-ICR-FT/MS data from the chondritic (A, C) and impact melt (B, D) samples; relative
abundance of assigned molecular compositions in four key molecular series (CHO (blue), CHOS (green),
CHNO (orange) and CHNOS (red), respectively).

125This chemical fingerprint and its distribution characteristics, with a high abundance of
CHNO and CHOS homologous series, showed significant differences between chondritic andimpact melt fractions in the Chelyabinsk meteorite. The similar distribution characteristics of allmolecular series, however, ensured that most of these organic compounds were no biogenic
contaminants from residence following the fall and subsequent handling. Terrestrial biologicalcontamination commonly shows known discontinuous signatures typical of biomolecules (e.g.
relative odd/even preferences for CHO molecules or clustering according to common classes of
biomolecules). Conceivable terrestrial impurities, while possibly present in trace amounts, left nonotable signature in the mass spectra of both meteorite extracts (Fig. S81).

Fig. S83. Count and distribution of the O, N, S atoms within the different chemical classes, showing thepeculiar changes of oxygen counts in soluble CHNO molecules when proceeding from the chondrite to
the impact or melt phase. (A) Count of sulfur and nitrogen atoms within the CHOS and CHNO series,
respectively, of the chondrite and impact melt extracts. Count of nitrogen versus oxygen atoms inchondrite (B) and melt fractions (C) in CHNO compounds. Count of oxygen atoms in CHOS (D), CHO(E) and CHNO (F) molecular series; note the shift in oxygen distribution within CHNO molecules during
processing of chondrite matter into melt phase.

126

The distribution of the elemental compositions of the two meteorite extracts is shown in Fig.
S83. Most of the CHNO and many CHOS compounds in the chondritic material contained only asingle heteroatom, i.e., one sulfur (CHOS1) or, alternatively, one nitrogen atom (CHN1O) per
molecule. The fraction of compounds with (ever) more than one heteroatom decreased rapidly
for both CHNO and less so for CHOS series (Fig. S83A), reflecting a lower tendency duringchemosynthesis to form these respective soluble compounds. The count and distribution of sulfur
within CHOS molecular series in the chondritic and the melt solvent extracts were almost
identical (Fig. S83A,D). In contrast, the distribution of nitrogen atoms within CHNO molecularseries showed a rather broad abundance maximum from CHN2-4O in the impact melt, reachingout to CHNO compounds with up to ten nitrogen atoms. Taking into account that in case of
Negative ESI ion detection, nitrogen-rich molecules will also carry sizable numbers of oxygen(Fig. S83B,C), one anticipates remarkable differences in oxygen distribution for chondritic andimpact melt CHNO molecules (cf. below).
When plotting the distribution of oxygen atoms according to molecular series (Fig. S83D-F),
a rather close accordance is found for both CHO and CHOS series for both chondritic and melt
materials, but not for CHNO molecules. The melt phase is depleted in oxygen-poor and enrichedin oxygen-rich CHNO molecules (Fig. S83F). In addition, when compared with CHO and CHNO
molecular series; CHOS compounds contain three more oxygen atoms on average in what seems
a bimodal distribution, suggesting compositional and structural preferences for molecules withsulfur in elevated oxidation states. High temperatures affecting the extraterrestrial organic matter
during the fall might have initiated a cascade of structural changes, including thermogenesis offunctionalized N-heterocycles with selective loss of volatiles, leading to a relative higher
methanol solubility of ionizable CHNO molecules in the melt relative to the chondritic phase.
The data show a high chemical diversity and abundance of soluble organic compounds in an
ordinary (non-carbonaceous) chondrite, based on C, H, N, O, and S belonging to continuous
homologous series reflecting their abiotic chemiosynthesis origin. In addition, the impact melt
fraction shows a significant increase in oxygen-rich CHNO compounds, suggesting that(precursors of these) polar soluble compounds were already present when these impact melts
were formed, and would have been accumulated during accretion and planetary formation. No
appreciable difference of relative oxygenation is observed for CHO and CHOS compounds in the127chondrite phase and impact melt, suggesting a different evolution of CHNO and CHOS
chemistry not only in Murchison [30] but also in the Chelyabinsk LL5 type meteorite.
4.12 Noble Gas Isotopes(Contributed by: K. Nagao, M. K. Haba, M. Komatsu, and T. Mikouchi)
Noble gas isotopes were measured for four chips from meteorite C3-2 (Table S13, Fig. S47),
and nine samples from seven commercially obtained Chelyabinsk meteorites (HR-1 to HR-7),
using a modified-VG5400(MS-3) mass spectrometer at the University of Tokyo. The HR
samples are from an unknown source and unknown location in the strewn field.
Table S24A. He and Ne isotopic ratios, and concentrations of noble gases in fragments C3-2 and HR-1 to
HR-7 of meteorite Chelyabinsk (LL5).
SampleMass
C3-2 (Bulk-1)
10.12mg ±C3-2 (Bulk-2)
32.15 mg ±C3-2 (Light)
3.20 mg ±C3-2 (Dark)
2.54 mg ±HR-1 (Bulk)
33.5 mg ±HR-2 (Bulk)
30.0 mg ±HR-3 (Bulk)
28.5 mg ±HR-4 (Bulk)
27.2 mg ±

3

4
He
He
10 cc/g 10-9 cc/g
4.3
116.4
0.4
8.6
5.8
131.1
0.4
9.3
5.5
117.6
0.8
8.3
8.0
118.4
0.8
7.5
311
353.7
20
24.2
200
98.3
20
9.9
902
1069.6
90
107.0
1421
121.7
146
12.2
-11

20

21

22

He/ He0.000370.000030.000440.000030.000470.00006
0.000680.00006
0.00880.00060.02040.00010.00840.00010.11680.0025

3HeNe
10 cc/g
0.219
0.018
0.705
0.048
0.570
0.046
3.187
0.221
1.381
0.091
0.560
0.057
1.911
0.192
0.948
0.103

Ne
10 cc/g
0.011
0.001
0.020
0.002
0.009
0.001
0.025
0.002
0.778
0.049
0.548
0.055
2.037
0.205
1.028
0.104

Ne
10-9 cc/g
0.036
0.002
0.094
0.006
0.072
0.005
0.383
0.024
0.945
0.057
0.608
0.061
2.244
0.225
1.146
0.115

3

4

-9

-9

20

Ne/22Ne21

Ne/22Ne

6.091
0.588
7.481
0.474
7.942
0.591
8.328
0.559
1.460
0.089
0.922
0.013
0.852
0.006
0.827
0.034

0.313
0.024
0.216
0.015
0.132
0.017
0.067
0.007
0.822
0.050
0.901
0.009
0.908
0.010
0.897
0.012

HR-5 (Bulk)

554

796.0

0.0070

3.547

3.836

4.195

0.846

0.914

25.5 mg ±HR-6 (Bulk)
25.9 mg ±HR-7 (Light)
31.6 mg ±HR-7 (Black)28.8 mg ±HR-7 (Bulk)*
501.8 mg ±

55
939
120
1254
83
1309
93
1245
125

79.7
2216.1
221.7
402.2
26.7
312.5
19.2
330.5
33.0

0.00000.00420.00030.03120.0021
0.04190.0026
0.03770.0002

0.355
0.644
0.065
2.285
0.160
3.724
0.210
2.883
0.289

0.386
0.730
0.074
2.454
0.177
2.989
0.192
2.763
0.277

0.420
0.817
0.082
2.743
0.195
3.569
0.222
3.033
0.303

0.005
0.789
0.012
0.833
0.051
1.044
0.065
0.951
0.004

0.009
0.894
0.010
0.895
0.054
0.838
0.050
0.911
0.008

* 81Kr was measured

128

A stepwise-heating noble gas extraction method (T = 600, 1000, 1300 or 1400, and 1700°C)
was applied to four C3-2 chips (2 bulk samples, one light and one dark color portion), HR-1
(bulk), HR-7 (light), and HR-7 (black). Noble gases were extracted from the bulk samples HR-2,
3, 4, 5, and 6 by total melting at 1700°C. Weights used for the noble gas analyses are listed inTable S24A. The concentration of 81Kr was measured for the HR-7 (bulk), the sample weighing
501.8 mg.
Table S24B. Ar isotopic ratios, and concentrations of noble gases in meteorite Chelyabinsk (LL5).
36

Ar
10 cc/g
3.981
0.266
5.879
0.331
6.365
0.368
10.185
0.610
3.769
0.262
3.495
0.353
4.309
0.434
0.463
0.050
7.674
0.771
0.794
0.083
3.661
0.239
6.100
0.372
3.126
0.313
-9

SampleC3-2 (Bulk-1)±
C3-2 (Bulk-2)±
C3-2 (Light)±
C3-2 (Dark)±
HR-1 (Bulk)±
HR-2 (Bulk)±
HR-3 (Bulk)±
HR-4 (Bulk)±
HR-5 (Bulk)±
HR-6 (Bulk)±
HR-7 (Light)±
HR-7 (Black)±HR-7 (Bulk)
±

38

Ar
10 cc/g
0.752
0.050
1.112
0.063
1.193
0.069
1.924
0.038
0.801
0.055
0.701
0.071
0.979
0.099
0.179
0.020
1.729
0.174
0.199
0.021
0.921
0.058
1.401
0.089
0.822
0.082
-9

40

Ar
10 cc/g
2228
141
2587
148
1605
86
4649
280
1304
88
674
68
4265
431
159
17
3944
397
7382
789
861
50
26875
1973
783
78
-9

38

Ar/36Ar

0.18900.015 80.18920.01070.18740.00980.18890.00640.21260.01480.20050.00100.22710.00260.38750.00530.22530.00100.25090.00430.25150.01750.22960.01020.26280.000940

Ar/36Ar
559.6
247.2
440.0
131.1
252.1
69.2
456.4
80.0
346.0
113.1
192.8
0.4
989.6
6.8
342.4
1.3
514.0
3.3
9296.4
200.8
235.1
61.5
4405.7
952.9
250.6
0.3

84

Kr
10 cc/g
168.8
9.6
178.8
10.0
275.7
15.7
279.2
16.2
46.0
2.4
110.2
11.0
65.5
6.6
11.8
1.2
97.7
9.8
30.8
3.1
44.0
2.4
185.0
11.7
49.0
4.9
-12

132

Xe
10-12cc/g
291.5
15.1
227.8
12.1
249.0
14.2
205.6
12.2
45.2
2.2
75.7
7.6
135.4
13.6
15.3
1.5
202.8
20.3
21.4
2.2
57.7
3.0
98.6
5.9
87.2
8.7

Tables S24A and S24B summarize the total concentrations and isotopic ratios of He, Ne, andAr, and concentrations of 84Ke and 132Xe. Krypton isotopic ratios, including 81Kr (T1/2 = 0.23My), for the sample HR-7(bulk) are presented in Table S24C. Isotopic ratios of Kr and Xe forother samples are not given here.
Cosmogenic He, Ne and 38Ar were clearly observed in the HR samples. The samples from129

C3-2, on the other hand show very low concentrations. This indicates that the C3-2 fragment wasderived from inside the large meteoroid, while the HR samples were from shallower parts of the
pre-atmospheric body. The HR-7 fragment had black portions larger than the typical scale ofmelt veins. Part of this black material, weighing about 30 mg, was used for noble gas analysis.
This material showed the highest concentration of 40Ar among the samples measured in this work,
which indicates enrichment in K in the black material.
Table S24C.

Kr isotopic ratios, and concentrations of 81Kr and 84Kr (10-12 ccSTP/g) in meteorite

Chelyabinsk HR-7 (Bulk).
SampleHR-7(Bulk)
±

84

Kr

81

78

Kr

Kr/
Kr

84

80

Kr/
Kr

81

84

Kr/
Kr

84

82

Kr/
Kr

83

Kr/
Kr

86

Kr/
Kr

84

84

84

49.0

0.01580.006390.04060.000322

0.20440.20300.30454.9

0.00190.000190.00050.000022

0.00070.00070.0012

Fig. S84. Helium isotope ratios versus helium concentrations.

Fig. S84 is a plot of 3He/4He versus 4He concentrations. The 3He/4He ratios of the C3-2
samples are in the range of primordial or solar wind He and relatively low concentrations of 4He,
suggesting negligible effect from cosmic-ray irradiation as well as loss of radiogenic 4He.
Presence of cosmogenic He in the HR samples is evident, but the concentrations are rather low
compared with those of most ordinary chondrites. Neon and Ar isotopic ratios plotted in Figs.
S85 and S86 also show a clear difference between the C3-2 and HR samples. Concentrations of

130

40

Ar in these meteorites are distinctly lower than those in unshocked ordinary chondrites. A

rough estimation of the K-Ar age for the samples shows young ages of about 1,000 My or less,which may be the time of a violent shock event, possibly the one that left the numerous melt
veins in the meteorites (Fig. 4A, main manuscript).

Fig. S85. Neon three isotope plot.

Fig. S86. Argon isotope ratios.

The shielding depth against cosmic-ray bombardment for each sample, and the cosmic-ray
exposure age for the Chelyabinsk meteoroid are estimated based on the cosmogenic noble gas
compositions measured in this work. Although the concentration of 81Kr was measured for the131sample HR-7 (bulk), the usual Kr-Kr method could not be applied due to the low concentrationof cosmogenic Kr in the sample. Because the concentration of 81Kr, 1.6 × 10-14 ccSTP/g, is in therange of the equilibrium level for ordinary chondrites, this fragment should have been at ashallow depth in the preatmospheric body. Calculation of the depth profile of 81Kr concentration
under 2π-geometry irradiation, following the method in Hohenberg et al. [157], indicates that theobserved concentration of 81Kr corresponds to a shielding depth of about 1 g/cm2. In thecalculation, the average concentrations of Rb, Sr, Y and Zr for other LL-chondrites were adopted.
The expected production rate of cosmogenic 21Ne under the same shielding condition of 1
g/cm2 is calculated to be 2.29 × 10-9 ccSTP/g/My (2π-geometry) following Hohenberg et al.
[157]. Combined with the measured concentration of cosmogenic 21Ne, 2.76 × 10-9 ccSTP/g forsample HR-7 (bulk), the cosmic-ray exposure is calculated as 1.2 My. Measured concentrationsof cosmogenic 21Ne for other HR samples from the same fragment, HR-7 (light) and HR-7
(black), are 2.45 and 2.98 × 10-9 ccSTP/g, respectively, and give similar exposure ages.

Fig. S87. Estimation of depth from the surface for each fragment in the preatmospheric body of the
Chelyabinsk meteoroid.

The depth profile of the 21Ne production rate, normalized to that at the shielding depth of 1
g/cm2, is shown in Fig. S87, where the production rate was calculated in the range from surface
to 500 g/cm2, following Hohenberg et al. [157], and extrapolated to about 400 cm in depth. An
average density of 3.3 g/cm3 (see Sect. 4.2) was used in the calculation. The observed 21Ne

132

production rate ratios for the measured samples, ranging from 1.39 for HR-5 (bulk) to 0.003 forC3-2 (light), may correspond to different depths, ranging from surface to ~300 cm beneath thesurface of the Chelyabinsk meteoroid. These data show that the diameter of the Chelyabinsk
meteoroid was larger than 6 m, which supports other estimates of about 20 m in diameter (seemain text). If that is the case, however, we can expect that fragments will be recovered derived
from deeper parts of the meteoroid that would have negligible effects from cosmic-ray
bombardment.

133

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