Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Flash Report on Damage Caused in Mexico City, Mexico, by the 2017
Puebla-Morelos Earthquake
Tsuneo OHSUMI
Dr., Research Center for Reinforcement of Resilient Function, National Research Institute for Earth Science andDisaster Resilience (NIED), Tsukuba, Japan
Email: t_ohsumi@bosai.go.jp

Hemanta HAZARIKA
Professor, Department of Civil Engineering, Kyushu University, Fukuoka, Japan, hazarika@civil.kyushu-u.ac.jp

ABSTRACTAn earthquake with a moment magnitude (Mw) of 7.1 occurred at 13:14 CDT (18:14 UTC) on September 19, 2017, inthe city of Puebla in Mexico. A damage survey was conducted in the affected area from November 18 to 21 by a teamfrom the National Research Institute for Earth Science and Disaster Resilience. This paper outlines the findings of thesurvey in terms of the various aspects of the earthquake that affected Mexico City and surrounding areas. It wasobserved that the main damage was to masonry reinforced concrete buildings and the most heavily damaged structures
correspond to areas underlain by soft soils 10–20 m in thickness. Comparison of estimated acceleration distribution forperiods of 1 s corresponds to 8–12 story buildings, and these period areas correspond to heavily damaged structures. We
show improvement of disaster resilience technology.
Key words: 2017 Puebla-Morelos Earthquake, Mexico City, Puebla, earthquake disaster, disaster re silience technology

1. Introduction
An earthquake with a moment magnitude (Mw) ofMexico City (CDMX)

7.1 occurred at 13:14 CDT (18:14 UTC) on September 19,
2017, in the city of Puebla, Mexico. The epicenter was incentral Mexico (18.58° N 98.40° W) at a depth of 51 km(USGS: U.S. Geological Survey). The earthquake wasofficially named the 2017 Puebla earthquake because theepicenter was located beneath the city of Puebla, and theshallow depth resulted in it being highly destructive.
Statistics provided by The National Coordinator of
Civil Protection of the Ministry of the Interior indicatethat 369 casualties were recorded on October 5. Mexico
City had the highest number of deaths (228), while 73
deaths were recorded in Morelos. A total of 45 deaths
were recorded in Puebla, 13 in the State of Mexico, 6 in
Guerrero and 1 in Oaxaca. Fig. 1 shows the maps ofMexico City (CDMX) and surrounds showing the survey
routes followed (red lines).

Fig. 1

Maps of Mexico City (CDMX) and surrounds

showing the survey routes followed (red lines)(OpenStreetMap https://www.openstreetmap.org/).

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2. Strong Motions

thickness.

2.1. Comparison of the 1985 and 2017 earthquakes
Fig. 2.1 shows a comparison of the Fourier spectra

Fig. 2.3 shows a comparison between seriously
damaged structures from the 2017 earthquake (red) andof different heights at sites CU (rocky ground) and SCT

the 1985 earthquake (blue). Periods were measured using(soft ground) for the 1985 earthquake (blue) and the 2017

microtremor measurements, with the base map derived

earthquake (red). According to UNUM report [1], Peakfrom Reinoso, E. and Lermo, J. (1991) [3]. The seriously

Ground Acceleration (PGA) in 1985 was 160 Gal, whiledamaged structures in 2017 were concentrated 1–2 sin 2017 PGA was 91 Gal. Peak Ground Acceleration

areas, while seriously damaged structures in 1985 were(PGA) is a measure of the severity of ground shaking.

concentrated in 3–4 s areas.

However, accelerations in the soil during the 2017
earthquake were most likely greater than those recorded

Fig. 2.4 shows transfer functions obtained from 10 m,
20 m and 40 m within the simplified soil profiles andin 1985 because of the complex movement pattern andsedimentary layers from one-dimensional analysis of thehigh spatial variability.

dominant frequency. The Vs values of the ground wereIn 1985, the ground response was amplified up to 7–

set from Facciolia and Flores (1975) [4] to FAS, which is

8 times at building sites located on the lake bed innormally consolidated clay, and DP, which is a sand layer

contrast to those located on hard rock in Mexico City.
During the 1985 earthquake, PGA at the soft soil site
(SCT) was significantly higher than at the rocky site(CU).
2.2. Comparison of seriously damaged structures fromthe 1985 and 2017 earthquakes
Fig. 2.2 shows a comparison between seriously
damaged structures from the 2017 earthquake (red) andthe 1985 earthquake (blue). The thickness of soft soils isalso shown; the base map derived from Martinez
Gonzalez, Jose (2015) [2]. The seriously damaged
structures in 2017 were concentrated in areas with 10–20
m soil thickness, while seriously damaged structuresfrom 1985 were concentrated in areas with 30–40 m soil

Fig. 2.1 Comparison of the Fourier spectra of different heights atsites (a) CU (firm ground) and (b) SCT (soft ground) for the 1985
earthquake (blue) and 2017 earthquake (red)(UNAM, Sep. 23, 2017）[1].

- 612 -Fig.2.2 Map showing the thickness soft soils anddamaged
structures(basemapfromMartinez Gonzalez, Jose, 2015) [2].

Fig. 2.3
Comparison between seriously damaged
structures. Periods were measured using microtremor
measurements, with the base map derived from Reinoso,E. and Lermo, J. (1991) [3].

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Fig. 2.4

Transfer functions were obtained from 10 m, 20 m and 40 m in the simplified soil profiles.

including gravel.

acceleration distribution for the 1.0 s period estimatedIn the 10 m case, the dominant period of transferfrom the roofs of buildings. All structures are within thefunctions is 0.645 s (1.6 Hz) and the amplification of

1.0 s acceleration period area (base map from UNAM,

ground motion is 5.3. In the 20 m case, the dominant2017) [5].

period of transfer functions is 1.1 s (0.95 Hz) and theamplification is 4.3. In the 40 m case, the dominantperiod of transfer functions is 2.0 s (0.5 Hz) and the3.2. Tlatelolco Complex area
The Tlatelolco Complex area was heavily damaged

amplification is 3.9. In the 1985 earthquake, which had

in the 1985 earthquake. For example, the 14-story RC

long-period components of earthquake motion, caused

Nevo Lion building in the Tlatelolco Complex, whichhigh amplification in soft soils. However, in the 10 m

included a north side and southern wing connected by ancase, which is shallow and segmented, the higher

Expansion Joint, suffered a collapse of the two north side

contrast Vs value of segmented layers and the basementbuildings that resulted in many casualties. After the 1985

contributed to increasing the amplification of groundearthquake, the Nevo Lion was renovated with newmotion in the 2017 earthquake, which had short-periodwings and walls with JICA (Japan International

components of earthquake motion.

Cooperation Agency) support (Fig. 3.4).
We visited the Tlatelolco Complex area to verify
this renovation. Structures designed and built with3. Survey Areas in Mexico City (CDMX)

earthquake-resistance showed no discernible damage

3.1. Buildings designated for demolition

after the 2017 earthquake based on external inspection.

In Mexico, seismic diagnosis of buildings isFig. 3.5 shows the lack of externally visible damage

undertaken by government. Based on the judgment

evident in the renovated Tlatelolco Complex after thefollowing the 2017 earthquake, it was decided that 132017 earthquake.

buildings would be demolished.
After obtaining approval from the Emergency
Committee, the demolition work started on October 10,

3.3. Damaged RC housings
Two adjacent housing blocks were built in the same2017 in the CDMX. There are 13 buildings alreadyperiod in 1970, as shown in Fig. 3.6, and both buildings

confirmed for demolition, since it was specified that inwill be demolished. However, the building on the rightthe first three cases, the state will use surveyors and anwas heavily damaged and the parking lot on the firstengineering team to determine the demolition method.

floor collapsed. The housing block on the left wasThese 13 buildings were selected as survey points in thisinspected, and found to have higher quality concrete thanstudy as shown in Figs. 3.1 and 3.2).

the right block. Also, the building column construction

Fig. 3.3 shows the demolition level structures with theused hoops/stirrups at a 45 cm pitch, while the- 613 -Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

hoops/stirrups were of very poor quality in the housing
block on the right.
3.4. Was the piloty structure damaged?
According to National Population Council, theestimated population for the metropolitan section ofMexico City in 2009 was approximately 8.84 millionpeople. According to the most recent definition agreed
upon by the federal and state governments, the Greater
Mexico City population is 21.3 million people, making it
the largest metropolitan area in the Western Hemisphere,

Fig. 3.1

thedemolition (Google Maps®)

tenth-largest

agglomeration,andthelargest

Map showing the 13 buildings designated for

Spanish-speaking city in the world. Most housingdevelopments are constructed with a dense overlapping
structure (Fig. 3.7), and the first floor has a piloty space.
The piloty structure of this space is typically weakly built,
and they have collapsed in many housing (Fig. 3.8).
3.5. Steel braces and concrete columns
In Mexico City, braces are installed on buildings todecrease the risk of blocks falling off, or bricks in thewall falling out of the plane of the building. Thus, a gable
wall between the brace is used to sustain a resilience
method. Buildings reinforced with steel braces are shownin Fig. 3.9 and typical diagonal reinforced concreteFig. 3.3 Map showing the distribution of the 13
structures designated for demolition level within the 1.0 s
acceleration period area.
(base map from Martinez Gonzalez, Jose, 2015).

bracing with masonry infill is shown in Fig. 3.10.

Fig. 3.2 Photographs of 13 buildings designated for demolition (photo taken by T. Ohsumi and Y. Dohi
on November 19, 2017)- 614 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Fig. 3.5 Photograph showing the lack of externallyvisible damage evident in the renovated Tlatelolco
Complex after the 2017 earthquake. (photo taken by T.
Ohsumi on November 19, 2017)

Fig. 3.4 Renovated Tlatelolco Complex, after the 1985
earthquake. (Courtesy of Prof. Nakano with Tokyo
Univ.)

Fig. 3.7 Typical housing in Mexico City.
(photo taken by T. Ohsumi on November 21, 2017)

Piloty space andcar were crashed.

Fig. 3.6 Comparison of damage to two housing blocks.
Note the heavily damaged housing on the right with poor
quality hoops/stirrups (photo taken by T. Ohsumi atNovember 19, 2017)

Fig. 3.9 Photographs of buildings reinforced with steel braces.

- 615 -Fig. 3.8 Piloty space crashed and the car were crushed.
(photo taken by T. Ohsumi on November 19, 2017)

Fig. 3.10 Masonry building which was reinforced withconcrete columns.
(photo taken by T. Ohsumi on November 18-19, 2017)

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

3.6. Latin American Tower
The Latin American tower was inaugurated on April30, 1956. It was designed by Adolpho Zeevaert, inconsultation with N. Newmark and Leonardo Zeevaert.
The Latin American Tower is a source of pride for theinhabitants of the Mexico City metropolis, as it brokeseveral engineering records during its construction using
Mexican technology. The structure survived the 1957,1978, 1979, 1985 and also the September 2017
earthquakes with only minor nonstructural damage. A
memorial plate was installed in the Latin AmericanTower (Fig. 3.11) and it describes how the Tower has
been able to sustain multiple episodes of strong seismicforces. Figs. 3.12 and 3.13 show the seismometer anddeformation

meterofthetower,

Fig. 3.11 Memorial plate in the Latin American Tower.
(photo taken by T. Ohsumi on November 21, 2017)

respectively.

Deformation is registered as the proportion of
movement within a range of permissible values in thetower. Fig.3.14 shows the Latin American tower
technology.

Fig. 3.12 Seismometer in theLatin American tower. (phototaken by T. Ohsumi on
November 21, 2017)

Fig. 3.13 Deformation meter in the Latin American Tower.
(photo taken by T. Ohsumi on November 21, 2017)

Fig. 3.14The Latin American tower technology.

30 Aniversario Sismo del 85: La Gran Urbe no Dejade Moverse, EL FINANCIERO- 616 -Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

to find people trapped under rubble. SEDENA uses

4. Transmission of Horizontal Forces in anEarthquake
The elements within a building that are most affectedwall-mounted scanners to search for people in collapsed

during an earthquake are the structural elements because

equipment sends out a signal to a specific point, andof the forces that are transmitted through them.

returns and informs if there is no vibration. Any

structures and works in the same way as radar. The

movement, even that of a finger, is recognizable by this4.1. What is a structural system?
It is important to note whether structures aredevice. The wall-mounted scanners have a range of up tocomposed of several elements, and have the function ofdetermine the depth and location of buried individuals.

supporting the loads that act on them seismically, by

All branches of SEDENA where collapses occurred havetransmitting them into the ground.

a team equipped with these scanners.

40 m, depending on the type of wall. It is able toIn addition, the “canine binomials” are important
4.2. Type of Cracks
The engineer Yoshio Joel Salinas, general director

additions to the rescue efforts, and consist of a trainedof T22 Coordination and Architecture, indicated that after

two, and with the individual being rescued, is one of trust

the earthquake it is necessary to detect the types ofand empathy. The dogs are able to detect even faint odors

cracks evident in buildings in terms of their relative riskof buried individuals and their physical dimensions allowof further failure (Fig. 4.1).

them to travel through smaller spaces than humans would

rescue dog and a handler. The relationship between thebe able to. Navy’s staff is responsible for training the5. Rescue Technology

dogs for 12 to 14 months, and they are employed in

5.1. Anything goes to find life: dogs and scanners
Scanning technology has progressed significantly

rescue tasks for six to seven years. Fig. 5.1 shows thesince 1985, and is used by the Armed Forces (such asbelow.

SEDENA in Mexico, Secretaría de la Defensa Nacional)

1) Uwb Detector: These detectors use radio technology atscanning technologies, which are described in detailFig. 4.1 Diagram showing the various type of cracks that can occur and should be monitored in a seismically damaged structure(courtesy of EL FINANCIERO, September 26, 2017)- 617 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Fig. 5.1 Schematic diagram of the five main types of scanning technology used in
post-earthquake rescue (courtesy of EL FINANCIERO, September 22, 2017)

bandwidths >500 MHz (UWB) to probe beneath thedistribution for the 1 s period corresponds to 8–12 story

surface of the debris for movement. The device detects

buildings. These period areas correspond to areas ofeven small movements of the chest caused by breathing.

heavily damaged

It locates victims by detecting movements up to 30 m

earthquake.

structures related

to the2017

away. The rescuers do require absolute silence during

In the 10 m case, which is shallow and segmented,

detection to accurately follow meaningful signals

the higher contrast Vs value of segmented layers and thebeneath debris.

basement contributed to increased amplification of2) Canine Binomies: These are the partnered dog andground motion in the 2017 earthquake, which hadtrainer, both prepared to search for people under rubble.

short-period components of earthquake motion.

A Harness may be used if they require it, and glasses

In Mexico City, minor damage was evident in urban

help protect the dog’s eyes in case of smoke, dust orbuildings with modified improvement of regulatory

other substances. Boots are also used to help protect theirrequirements in terms of construction that were in placelegs. Frida is a dog that belongs to the canine section ofafter the 1985 earthquake. Conversely, buildings not

the Mexican Navy Secretariat, and she has managed tosubject to these regulatory requirements were more

rescue 52 persons and has collaborated in rescue work inheavily damaged.

Honduras, Ecuador and Haiti.
3) Thermal Equipment Reading: Thermal equipment isused to locate people beneath the rubble. The rescue ofReferences
Grupos de Sismología e Ingeniería de la UNAM Nota

those who are buried in debris without injuries and who

Informativa ¿Qué ocurrió el 19 de septiembre de 2017

can move freely is relatively easy with this method. In

en México?, 23 de septiembre de 2017.

the event that an individual is injured or trapped aMartinez Gonzalez Jose. 2015. Subsidencia regional ytourniquet can be used and vital signs are checked,respuesta sismica en ciudad deMexico: el sismo del 19

followed by their recovery.

de Septiembre, 1985 (Ms 8.1).

4) Wall Scanning: The wall scanning equipment allows

Reinoso, E. y Lermo, J. 1991. Periodos del suelo del valle

users to observe an area from behind a wall. The scannerde México medidos en sismos y con vibración

detects micro-shocks caused by breathing, heartbeat orambiental. Proceedings of the IX National Conference

physical gestures of people trapped.

on Earthquake Engineering, Manzanillo, Colima,
México, pp. 2,149-2,156.

6. Findings
Based on the study presented, and the survey results,Facciolia and Flores. 1975. Respuestas Sismicas Maximas
Probables en las Arcillas de la Ciudad de Mexico,the following conclusions can be drawn:

Universidad Nacional Autonorna de Mexico.

Heavily damaged structures in the Mexico City area

Sismo del día 19 de Septiembre de 2017. Puebla-Morelos

related to the 2017 earthquake are underlain by areas(M 7.1), Sismo del día 19 de Septiembre de 2017,consisting of soft soils 10–20 m in thickness.

Puebla-Morelos (M 7.1), Reporte Especial, UNAM.

Comparisonoftheestimatedacceleration- 618 -