MISSILE IMP ACT CRATERS 

(WHITE SANDS MISSILE RANGE, NEW MEXICO) 

AND APPLICATIONS TO LUNAR RESEARCH 
Crater produced by missile impact in silty sand and sandy silt, oblique 

view. Missile traveled along an oblique trajectory, 45.8° from the 

horizontal with a kinetic energy of 25.l x 1014 ergs. The crater, 

about 6 metres across, and ejecta have bilateral symmetry because 

of the oblique trajectory. Trace of path of missile is shown by arrow. 

Small depressions in foreground are footprints. Crater 24; 

photograph courtesy of U.S. Army. 
Missile Impact Craters 

(White Sands Missile Range, New Mexico) 

and Applications to Lunar Research 

By H. J. MOORE 

CONTRIBUTIONS TO ASTROGEOLOGY 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 812-B 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1976 
UNITED STATES DEPARTMENT OF THE INTERIOR 

THOMAS S. KLEPPE, Secretary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Director 

Library of Congress Cataloging in Publication Data 

Moore, Henry J. 

Missile impact craters (White Sands Missile Range, New Mexico) and their applications to lunar research. (Contributions to 

astrogeology) 

(Geological Survey Professional Paper 812-B) 

Bibliography: p. B41-B43. 

Supt. of Docs. No.: I 19.16:812-B 

1. Lunar craters. 2. Cryptoexplosion structures-New Mexico-White Sands region. 3. Lunar geology. 4. Guided missiles. 

I. Title: Missile impact craters ... II. Series. III. Series: United States. Geological Survey. Professional Paper 812-B. 

QB591.M57 551.3 75-619096 

For ~ale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 

Stock Number 024-001-02786-1 
CONTENTS 

Page Page 

1\bstract -------------------------------------------------- B1 Quantitative relations ____________________________________ B25 

Introduction _ _ _ _______ ________ _ _ _ _ ______ ____ ________ _ _ _ _ __ 1 

Purpose and scope ofreport ---------------------------- 2 

Fieldwork ______ _ _____ __ _ _ ______ _ _ _ _ __ _ _ ______ ________ 2 

1\cknowledgments _ _ __________ _ _ ____ ____ _ _ _ _____ _ _ _ _ _ _ 2 

Procedures ------------------------------------------------ 3 

Support data ------------------------------------------ 3 

~apping ---------------------------------------------- 3 

Target material -------------------------------------- 3 

Explosives used________________________________________ 3 

Definitions _ _ ____ _ _ ___ ___ _ _ ___ _____ _ _ __ ____ __ _ _ _ _ ____ __ 3 

Description of craters -------------------------------------- 4 

Crater morphology ------------------------------------ 4 

~ap units -------------------------------------------- 6 

Distribution ____ __ _ _ _________ _ ____ ____ __ _ _ _____ _ _ _ __ __ 9 

Secondary impacts _ _ ______ _ _ _ _ ______ ____ _ _ __ __ __ _ _ __ _ _ 11 

Deformation ------------------------------------------ 12 

Zones of subsurface deformation ____________________ 16 

~ixed breccia -------------------------------- 16 

Sanded material ------------------------------ 17 

Zone of conjugate fractures ____________________ 17 

Tilted and broken material ____________________ 17 

Zone of open fractures __________________________ 18 

~issile-impact crater size and energy __________________ 25 

Comparison with other data on experimental impacts ____ 25 

Comparison with craters produced by explosives ________ 29 

Discussion of data ---------------------------------------- 31 

Symmetry and path of missile -------------------------- 31 

1\ngle of impact -------------------------------------- 31 

Crater size and energy -------------------------------- 32 

Compression of target material ________________________ 33 

Water content __ _ _ _____ _ ____ _____ _____ ________ __ ______ 34 

Extrapolation to larger sizes ____________________________ 34 

1\pplications to lunar problems ---------------------------- 35 

Nature of lunar surface -------------------------------- 35 

Ranger and other impacts------------------------------ 36 

Surveyor imagery ______________________________________ 36 

Passive seismic experiment ---------------------------- 37 

1\pollo orbital photographs ---------------------------- 37 

1\stronaut training ------------------------------------ 37 

Lunar samples __ ------ _____________________ ----------- 38 

Summary and conclusions---------------------------------- 39 

References cited ------------------------------------------ 41 

ILLUSTRATIONS 

FRONTISPIECE. Oblique view of missile impact crater. 

FIGURE 1. Diagram showing terms used in text -------------------------------------------------------------------------- B4 

2. Contour map and profiles of typical missile impact crater in gypsiferous alluvium and fixed gypsum dune __________ 5 

3. Contour map and profiles of small missile· impact crater in gypsum lake bed-------------------------------------- 6 

4. Contour map and profiles of large missile impact crater in gypsum lake bed-------------------------------------- 6 

5. Photograph of crater in sand produced by missile impact-------------------------------------------------------- 7 

6. Contour map and profiles of crater in colluvium ---------------------------------------------------------------- 7 

7. Sketch maps of crater in fixed gypsum dune, showing mapped units --------------------------------------------- 8 

8. Photograph of thick ejecta from missile impact crater in dry sandy alluvium______________________________________ 8 

9. Profile of missile impact crater showing inverted stratigraphy -------------------------------------------------- 8 

10. Photograph of inverted sequence exposed in upper crater wall -------------------------------------------------- 9 

11. Photograph of thin to discontinuous ejecta around missile impact crater------------------------------------------ 9 

12. Photograph of scattered ejecta f:t:om crater in clayey silt and silty clay-------------------------------------------- 9 

13. ~ap illustrating limit of throwout and scattered ejecta---------------------------------------------------------- 9 

14. Photograph of shattered and fractured target material exposed on up-trajectory wall of crater______________________ 10 

15. Photograph of variations in ejecta distribution around craters in fixed gypsum dunes______________________________ 10 

16. Photograph of ejecta ·from craters in layered targets ------------------------------------------------------------ 11 

17. ~ap of crater in water-saturated gypsum lake beds showing distribution of secondary impacts, thin to discontinuous 

ejecta, and thick ejecta____________________________________________________________________________________ 13 

18-26. Photographs showing: 

18. Secondary crater nearly filled by ejecta that produced it_ _________________________________________________ 14 

19. Secondary impacts beyond thin to discontinuous ejecta -------------------------------------------------- 14 

20. Secondary craters in thin to discontinuous ejecta -------------------------------------------------------- 14 

21. Secondary crater produced by fragment from gray layer -------------------------------------------------- 15 

22. Secondary craters in moist ripple-marked sand ---------------------------------------------------------- 15 

23. Secondary craters produced by fine ejecta impacting cohesionless gypsum sand ---------------------------- 15 

24. Pile of debris and scattered f:r:agments from crater in gypsiferous alluvium -------------------------------- 15 

25. Sheared and compressed target material and coated rocks ------------------------------------------------ 16 

26. ~issile impact crater in indurated gypsum dunes -------------------------------------------------------- 17 

27. Cross section through same crater parallel to plane of trajectory ------------------------------------------ _______ 18 

v 
VI CONTENTS 

Page 

FIGURE 28--32. Photographs showing: 

28. Mixed breccia below crater floor ________________________________________________________________________ B19 

29. Cataclastic injection of mixture of projectile and gypsum fragments into sanded zone ---------------------- 19 

30. Sanded material and banding _____ _ _ _ __ ______ _ _ ________ __ ________ ____ __ ________ __ ______ __ _____ _ ______ __ 19 

31. Conjugate fractures ------------------------------------------------------------------------------------ 19 

32. Tilted and broken material exposed in upper wall of crater ---------------------------------------------- 20 

33. Plot of seismic velocities as a function of distance from crater rim ---------------------------------------------- 20 

34. Plot of shear-vane measurements for crater in fine silty sand and sandy silt -------------------------------------- 21 

35. Photograph of open fracture near up-trajectory edge of crater -------------------------------------------------- 21 

36. Cross sections through craters _ _ _ _ _ _ __ _ _ _ _ ____ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ ___ _ _ _ _ _ ______ _ __ _ _ _ _ __ _ _ __ _ _ __ _ _ _ _ _ ___ __ _ ___ _ _ _ _ 22 

37. Photographs of missile impact craters in rock __ _ _ ________ _ _ __________ ___________ _ ______ ________ ________ _______ _ 23 

38. Cross section showing structures in rims of craters in water-saturated gypsum lake beds --------------------------- 23 

39. Plot showing the six categories of projectile deformation and degree of burial of projectile or pieces of projectile 

resulting from impact ------------------------------------------------------------------------------------ 24 

40. Photographs of sawed sections of impacts with diatomaceous earth of a BB, .22-caliber bullet, and chrome steel sphere _ _ 24 

41-53. Graphs showing: 

41. Comparison between average rim height and rim radius__________________________________________________ 26 

42. Comparison between apparent crater depth and apparent crater radius ------------------------------------ 26 

43. Comparison between the sum of apparent crater depth and rim height with rim radius -------------------- 27 

44. Comparison between apparent radius of crater and kinetic energy of missile ------------------------------ 27 

45. Comparison between apparent radius of crater and product of sine of angle of impact and kinetic energy of missile 27 

46. Comparison between rim radius and kinetic energy of missile -------------------------------------------- 28 

47. Comparison between apparent depth and kinetic energy of missile --------------------------------------- 28 

48. Comparison between apparent crater volume and kinetic energy ------------------------------------------ 28 

49. Comparison of displaced mass and kinetic energy of missile ---------------------------------------------- 29 

50. Comparison of displaced mass and product of sine of angle of impact and kinetic energy of missile __________ 29 

51. Ejected or displaced mass and kinetic energy corrected for angle of impact, and extrapolation of hypervelocity 

impact data on craters in rock and sand ------------------------------------------------------------- 30 

52. Comparison of displaced masses of craters produced by chemical explosives (1966), chemical explosive experiments at White Sands Missile Range, and missile impact craters-------------------------------------- 30 

53. Comparison of impact and explosive craters in dry to moist targets and water-saturated targets ------------ 31 

54. Traces of missile paths estimated from crater morphology and ejecta distribution--------------------------------- 32 

55. Graph of peak shock pressures produced at impact of nylon and aluminum projectiles and compression oftarget 

materials------------------------------------------------------------------------------------------------ 33 

56. Comparison of data on craters produced by explosives and impact ---------------------------------------------- 35 

57-62. Photographs showing: 

57. Effect of resolution on appearance of craters formed in rock ------------------------------------------ 36 

58. Ranger IX frame showing craters down to 1 m across ----------------------------------------------- 36 

59. Craters produced by Ranger impacts ---------------------------------------------------------------- 37 

60. Secondary impact craters on lunar surface near Surveyors VII and I ---------------------------------- 38 

61. Apollo 16 Panoramic Camera photograph showing 2-km diameter crater ------------------------------ 38 

62. Lunar samples similar to ejected fragments around missile impact craters ---------------------------- 39 

TABLES 

Page 

TABLE 1. General classification of target materials for missile impacts----------------------------------------------------- ____ B3 

2. Results of least squares fits to missile impact data ___________________________________________________________________ 25 

3. Data on missile impacts-lithologic description and physical parameters ----------------------------------------- ____ 44 

4. Data on explosive craters-lithologic description and physical parameters _____________________________________________ 47 
Metric unit 

millimetre (mm) metre (m) 

kilometre (km) 

square metre (m~) 

square kilometre (km~) 

hectare (ha) 

cubic centimetre lcn1'1) 

litre (l) 

cubic metre (m:l) 

cubic metre cubic hectometre (hm~) 

litre 

litre 

litre 

cubic metre 

cubic metre 

gram (g) 

gram 

tonne (t) tonne 

kilogram per square 

centimetre (kg/cm2) 

kilogram per square 

centimetre 

cubic metre per second 

(m3js) 

CONTENTS VII 

METRIC-ENGLISH EQUIVALENTS 

English equivalent 

Length 

o.o:m;H inch (in) 

:-l.:!8 feet (ft) 

.62 mile (mi) 

Area 

10.76 .38!) 

:!.47 

Volume 

0.061 

61.0;{ 

3().31 .00081 =S10.7 2.113 

1.06 

.26 

.00026 

6.290 

Weight 

O.OH5 

.0022 

1.1 

.ns 

square feet (ft2) 

square mile (mi~) 

acres 

cubic inch (in3) 

cubic inches 

cubic feet (ft3 ) 

acre-foot ( acre-ft) 

acre-feet 

pints (pt\ 

quarts (qt) 

gallon (gal) 

million gallons {:\!gal or 106 gal) 

barrt'ls ( bbl) ( 1 bbl = 42 gal) 

onncP. avoirdupois (oz avdp) 

vound, avoirdupois (lb anlp) tons. short {2,000 lb) 

ton, long (2,240 lb) 

Specific combinations 

O.fl6 

.98 

8G.3 

atmosphere (atm) 

bar (0.986fl atm) 

cubic feet per second (ft3/s) 

:\Ietric unit English equivalent 

Specific combinations-Continued 

litre per second (1/s) 

cubic metre per second 

per square kilometre 

[(m3/s)/km21 

metre per da;r (m/!1) 

metre per kilometrP 

(m/km) 

kilometre per hour 

(km/h) metre per second (m/s) metre squared per day 

(m2/d) 

cubic metre per second 

(m3/s) 

cubic metre per minute 

(m3 /min) 

litre per second (1/s) 

litre per second per metre [(1/s)/m] 

kilometre per hour 

(km/h) metre per second (m/s) 

gram per cubic 

centimetre (g/cm-1) 

g-ram per square 

centimetre (g/cm2) 

gram per square 

centimetre 

degree Celsius (°C) 

degrees Celsius 

( tPmperature) 

.0353 

!11.47 

:::.28 

.9113 

:~L28 

10.764 

= 22.826 

=264.2 

15.85 

4.83 

.62 

2.237 

.0142 

cubic foot per second 

enbic feet per second per 

square mile [ (fts/s) /mi2] 

feet per day (hydraulic 

conductivity) (ft/d) 

feet per mile (ftjmi) 

foot per second (ft/s) 

feet per second 

feet squared per day (ft2/d) 

(transmissivity) 

million gallons per day 

(Mgal/d) 

gallons per minute (gal/min) 

gallons per minute 

gallons per minute per foot 

[(gal/min) /ft] 

mile per hour (mi/h) 

miles per hour 

pounds per cubic foot (lb/ft3 ) 

pounds per square foot (lb/ft2) 

pound per square inch (lb/in2) 

Temperature 

1.8 degrees Fahrenheit ( °F) 

= [ (1.8 X °C) + 32] degrees Fahrenheit 

CONTRIBUTIONS TO ASTROGEOLOGY 

MISSILE IMP ACT CRATERS 

(WHITE SANDS MISSILE RANGE, NEW MEXICO) 

AND APPLICATIONS TO LUNAR RESEARCH 

By H. J. MOORE 

ABSTRACT 

Craters in natural materials at White Sands Missile Range, N. 

Mex., were produced by the impact of high-velocity to hypervelocity 

missiles traveling along oblique trajectories with kinetic energies 

between 2.1 and 81x 1014 ergs. The oblique impacts produce craters 2 

to 10 m across with morphologies and ejecta that are bilaterally 

symmetrical with respect to the plane ofthe missile trajectory. Rims 

are high and the amount of ejecta large in down-trajectory and lateral 

directions, whereas rims are low to nonexistent and ejecta thin to 

absent up-trajectory. Symmetry development and modifications of the 

symmetry are a function of target material, local topography, and 

angle of impact. 

Seven mappable units can be recognized in and around the craters. 

Three of these are ejecta: thick ejecta near the crater, thin to discontinuous ejecta at greater distances, and scattered ejecta at the greatest 

distances to the limit ofthrowout. These ejecta units may be absent on 

the up-trajectory side; if present, they are rarely as thick or continuous as on other sides of the crater. Three units are target materials: 

undeformed target material exposed in local patches through thin to 

discontinuous ejecta and everywhere between the fragments of 

scattered ejecta, tilted and broken target material exposed in upper 

crater walls, and shattered and fractured target material exposed on 

the up-trajectory crater wall. The seventh unit is slope material 

composed of talus and fallback within the crater. Development, 

character, and exposure of these units varies chiefly with the target 

material. 

Ejecta from the craters is chiefly broken but relatively undeformed 

target material that may range in size from very fine grained debris to 

large blocks. Where the target is porous, significant amounts of the 

ejecta are composed of sheared and compressed fragments, some 

coated with dark layers of mixed projectile pieces, powder, and fused 

metal mixed with crushed target material. For layered targets, the 

original stratigraphic sequence is crudely preserved and in inverted 

order in thick ejecta. 

Secondary impact craters are produced by the impact of ejected 

fragments when the surrounding surface materials are sufficiently 

weak. A wide variety of secondary impact crater relations may result. 

Secondary craters nearest the primary crater have blocks in them that 

are larger than or the same size as the crater they produced. Farther 

from the primary crater, the fragments are generally smaller than the 

secondary crater and are ejected from it. 

Excavation of four craters revealed a mixed breccia beneath the 

crater floor composed of missile pieces, sheared and compressed target 

material, and crushed debris. Banded, disaggregated target material 

and nonmixed breccia surrounded the mixed breccia, and these 

breccias were surrounded by a zone of conjugate fractures. Beneath 

the ejecta on the lateral and down-trajectory crater flanks, the target 

materials were tilted upward and broken. Up-trajectory, open 

fractures and downward displacement occurred in two ofthe craters. 

No displacement was observed for the other two. 

Beneath the down-trajectory rims of craters with distinct layering, 

overturned synclines were observed. 

Missile breakup and behavior during cratering are a function of 

target and missile properties. Missile breakup depends on missile 

velocity and is most extensive at high velocities, where the missile is 

fragmented, powdered, and partly fused. Burial of missile or its 

fragmented, powdered, and fused remains is greatest for porous 

targets and least for dense cohesive targets. For very porous targets, 

camouflet structures containing the fragmented missile may form. 

Least squares fit to the data on craters in dry to moist targets 

indicate 

where Va is the volume of the apparent crater and Ep is the kinetic 

energy ofthe missile. This equation is consistent with expectations of 

the equations relating apparent depth and radius to kinetic energy. 

Extrapolation of displaced masses and kinetic energies for laboratory 

impacts with sand and rock converge near 1015 to 1016 ergs, whe:re the 

extrapolations are near the data on missile impact craters, corrected 

for impact angle. 

Displaced masses of craters produced by missile impacts and by 

chemical explosives with small scaled depths of burial are about the 

same when the kinetic energies ofthe missiles (corrected for angle of 

impact) are equal to the TNT equivalent energy of the explosive. The 

problem of equivalent scaled depth of burst for an impact crater is 

complicated and not entirely resolved, however. Both missile impact 

craters and chemical explosive craters in water-saturated targets are 

larger than their counterparts in dry to moist materials. 

Data collected during the study of missile impact craters have 

helped resolve a number of problems in lunar research: (1) the soillike 

nature of lunar surface materials was predicted, (2) sizes of craters 

produced by artificial impacts were correctly predicted, (3) certain 

features imaged by Surveyor were found to be analogous to features 

associated with missile impact craters, (4) missile impacts were used 

in support of the Apollo passive seismic experiment, (5) craters seen in 

Apollo orbital photographs were found to be similar to some missile 

impact craters, (6) missile impact craters supplied data on sample 

collection and crater phenomenology used in training astronauts, and 

(7) some returned lunar samples are similar to coated, sheared, and 

compressed fragments ejected from missile impact craters. 

INTRODUCTION 

The advent of lunar exploration with manned and 

unmanned spacecraft brought renewed interest in 

experimental and natural craters produced by projectile 

impacts in natural materials. Experiments producing 

B1 
B2 CONTRIBUTIONS TO ASTROGEOLOGY 

craters by the impact of low-velocity projectiles with 

clay, powder, and mud were employed by early investigators in their lunar studies (for example, Hooke, 

1664, p. 242-246; Meydenbauer, 1882; Gilbert, 1893). 

Later, morphologies of craters produced by bombs with 

explosive warheads were compared with morphologies 

of lunar craters (lves, 1919, and Baldwin, 1949). 

Baldwin (1949, 1963) included craters with shallow 

depths of burial in his lunar studies and estimated the 

energy required to produce Meteor Crater in Arizona. 

Shoemaker (1960, 1962) mapped and studied craters 

produced by nuclear explosives with shallow depths of 

burial, compared them structurally with Meteor Crater, 

then developed a ballistics model that accounts for 

ejecta from lunar craters. 

Light-gas guns capable of accelerating projectiles to 

velocities exceeding 7.0 km/s (Curtis, 1962, Charters 

and others, 1957) permitted experimentation with 

targets of rock and sand under conditions where high 

pressures were attained during impact cratering 

(Charters, 1960; Shoemaker and others, 1963; Moore 

and others, 1962; Moore and others, 1964a; Gault and 

others, 1965; and Oberbeck, 1970). Most of the craters in 

these experiments were 1.0 to 70 em or so across. 

Microparticle accelerators provided data on 

micrometre-size impact craters (Mandeville and Vedder, 1971). These data have been applied to lunar 

studies in many ways. 

PURPOSE AND SCOPE OF REPORT 

Studies of more than 50 craters produced by the impact of missiles were conducted by the U.S. Geological 

Survey at White Sands Missile Range, N.Mex., from 

February 1964 to January 1973. The purposes of these 

studies were to extend our knowledge of hypervelocity 

experimental impact craters in natural terrestrial 

materials to large craters produced by projectiles with 

large kinetic energies, to compare the dimensions and 

characteristics of the impact craters with craters 

produced by chemical explosives, and to apply the 

knowledge gained from the impact craters to lunar 

problems. This paper provides data on missile impact 

craters 2 to 10m across produced in natural materials 

by missiles with kinetic energies between 2.1 x 1014 and 

81 x 1014 ergs traveling along oblique trajectories. 

Information released earlier on missile impact craters is available in preliminary status reports and short 

papers (Moore, 1971a, 1969, 1968a, 1966a, b, c; Moore 

and Lugn, 1965; Moore and others, 1964a; Moore and 

others, 1968; Moore and others, 1967; Latham and 

others, 1970) that present preliminary results and 

interpretations, some of which have been modified since 

the reports were written. 

FIELDWORK 

Fieldwork was begun in February 1964 by Reuben 

Kachadoorian of the U.S. Geological Survey, who 

studied the first three impact craters. H. J. Moore 

mapped and studied two craters in April 1964. 

Fieldwork continued through January 1973, conducted 

primarily by H. J. Moore, Reuben Kachadoorian, and 

Peter Margolin of the U.S. Geological Survey. 

ACKNOWLEDGMENTS 

The Command at White Sands Missile Range, N. 

Mex., made this study possible by allowing access to the 

craters, furnishing kinetic energies and angles of impact of the missiles, providing ground and aerial 

photography, and helping in countless other ways. 

Without this support, the study could not have been 

conducted. 

The author wishes to specifically acknowledge the 

contributions of the following individuals who were 

within the Command at White Sands during the study: 

PaulK. Arthur, Robert E. Ball, Carlos A. Bustamante, 

Donald Cramer, Captain Ronald J. Hoekzema, S. V. 

Jennings, Johnnie G. Losack, Frank A. McKenna, Eli 

H. Mabry, JohnJ. Ofenloch, Major George Wallace, and 

many others. Valuable help was furnished by the Inland 

Range Field Office in particular by Captain John Thau 

and Lt. James Forman. The many geologists of the U.S. 

Geological Survey and other individuals who helped in 

mapping of craters are acknowledged in table 2 (p.B25). 

Sustained mapping by Reuben Kachadoorian and Peter 

Margolin is especially appreciated. During the early 

phases of the study aid was given by Donald E. Gault, 

William L. Quaide, and Verne R. Oberbeck, of Ames 

Research Center, National Aeronautics and Space 

Administration, Moffett Field, Calif. Richard V. Lugn 

and Francis G. Robertson provided useful support in 

drafting, planimetry, and measurements of densities 

and moisture contents of samples. Experiments using 

commercial explosives were designed and performed by 

Gary V. Latham, Arthur McGarr, and William G. 

McDonald, of the Lamont-Doherty Geological Observatory of Columbia University. Work was performed 

under NASA contracts R-66 and W-13,130. 

In addition to the photography furnished by the 

Command at White Sands, vertical photography and 

imagery of selected craters was obtained using color, 

black and white, and ultraviolet film and an infrared 

scanner by the Nat ural Resources Program Remote 

Sensing Aircraft (NASA 926 CV 240A) piloted by 

Kenneth Haugen of the Manned Spacecraft Center, 

Houston, Tex. 

The U.S. National Park Service allowed access to 

several craters. 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B3 

PROCEDURES 

SUPPORT DATA 

Data on kinetic energies and angles of impact were 

supplied by the Command at White Sands from known 

masses, velocities, and trajectories of the missiles. 

When unclassified, measured velocities and masses of 

the missiles were furnished. 

MAPPING 

Topographic maps of the craters were prepared using 

a telescopic alidade, planetable, stadia rod, and tape at 

scales of 1:24 to 1:48, depending on the size of the crater. 

Part of the ejecta and limits ofthrowout were mapped at 

smaller scales. Some mapping was facilitated using 

photography and imagery furnished by the Command 

at White Sands Missile Range and the Earth Resources 

Program of NASA. Cross sections along trenches were 

prepared using a planetable, alidade, and tape for 

primary control. A stretched tape was used to fill in 

details. 

Crater dimensions were obtained from the topographic maps. Crater volumes were calculated using 

areas obtained with a compensating planimeter from 

the topographic maps and the known contour interval. 

Dimensions taken from images were measured directly 

on the images, then computed using scales obtained by 

comparing lengths between image points and measured 

distances between corresponding points on the ground. 

TARGET MATERIALS 

Target materials ranged widely in their physical 

properties; they include rock, cohesive gypsum sand 

(fixed gypsum dunes), lake beds, alluvium, colluvium, 

soils, and sand. In general, target materials were dry to 

moist but some lake beds were water-saturated. In table 

2 target materials for each crater are briefly described 

using the Unified Soil Classification System (U.S. Army 

Corps of Engineers, 1953), along with geologic descriptions, densities, and moisture contents obtained 

using techniques outlined in the Earth Manual (U.S. 

Bureau of Reclamation, 1963). Special precautions had 

to be taken, because many of the target materials 

contained gypsum, which changes to water, basanite, 

and anhydrite when heated to 90°C and higher. 

Measurements of target strength and changes in 

strength resulting from deformation were obtained 

using shear vanes, a small compression apparatus, and 

a shear box. Sound velocities were obtained for two 

target types using standard seismic equipment. Properties of target materials are summarized in table 1 

insofar as possible. 

EXPLOSIVES USED 

Explosive experiments were designed and performed 

by Gary V. Latham, Art McGarr, and William 

McDonald of the Lamont-Doherty Geological Observatory of Columbia University, using 5 to 100 kg (11 to 

220 lb) of sticks of Amogel1 (Apache Powder Co.) and 

Amodyte 1 (Atlas Chemical Industries). 1 According to 

the manufacturers, the energy release of these explosives is about 3.9x 1013 ergs/kg (1.77x 1013 ergs/lb). 

By comparison, TNT yields about 4.2x 1013 ergs/kg 

(1.9 x 1013 ergs/lb) (Nordyke and Wray, 1964, p. 675). 

DEFINITIONS 

A number of parameters are defined below and illustrated in figure 1. 

TRAJECTORY TERMS 

Path of missile: The line described by the inflight 

missile just before impact (BO). 

Plane of trajectory: The plane defined by the path of 

the missile in flight and the local vertical (BOC). 

Trace of missile: A line formed by the intersection of 

the plane of the trajectory and the local horizon-

'Mention ofthese companies and their products does not constitute an endorsement ofthem 

by the U.S. Geological Survey. 

TABLE 1.---General classification of target materials for missile impacts 

Target material Moisture content Bulk density, 

g/cm3 

Water-saturated Wet, up to 30 percent 1.2-1.85 gypsum lake beds water 

Gypsum lake beds Moist, 7-13 percent 1.8-1.9 water 

Fixed gypsum dunes Dry, 1-7 percent 1.37-1.56 water 

Colluvium Dry, 1-7 percent 1.2-1.8 water 

Alluvium and soil Usually dry, 1.1-2.1 1-7 percent water 

Sand Dry, 1-7 percent 1.35-1.60 water 

Rock Dry, no water 2.5 

'Number in parenthesis is depth for shear-vane strength; sis near surface. 

Sound velocity, 

km/s 

0.93 

.25 

Shear-vane strength 1 , 

bars 

30 (1m) 

3.0 (s) 

0.8-4.0 (s) 3.0-6.0 (l ml 

0 (sl 

2.0 (0.3 ml 

0.5-2.0 (s) 5 -11.5 (l m) 

0 (s) 

5(lml 

Very large 

Unified 

Soil Class 

SM, SC,ML 

CL,ML 

ML 

SM 

ML 

sw 

SP 

Rock 
B4 CONTRIBUTIONS TO ASTROGEOLOGY 

A 

D 

y 

B 

c 

/ 

/ r--

1 

I 

I 

I 

z 

c ~-----71 

""-.. /1 ""-.. / 

""-.. I 

I 

I 

I 

I 

A~ 

I 

FIGURE 1.-Physical parameters, terms defined in text. A: BO, path 

of missile; AO, trace of missile; BOC, plane of trajectory; 0 to A, 

up-trajectory direction; A to 0, down-trajectory direction; area near 

AO, beneath the trajectory; OD, OE, lateral directions; angle AOB, 

angle of impact; 0, point of impact; z is vertical and x and y are 

horizontal. B: D~, rim diameter; Da, apparent diameter; da, apparent crater depth; h, rim height. C, Plane perpendicular to plane 

of trajectory. 

tal plane, terminating at the point of impact 

(AO). 

Up-trajectory: The general direction from the point 

of impact toward the origin or launch site of the 

missile (direction of OA ± several tens of degrees). 

Down-trajectory: The general direction from the 

point of impact away from the origin or launch 

site of the missile (direction of AO ± several tens 

of degrees). 

Beneath the trajectory: Areas near the crater that 

are below the path of the missile (near the line 

AO). 

Lateral direction(s): The direction(s) from the point 

of impact more or less perpendicular to the plane 

of the trajectory (direction(s) of OD and OE ± 

several tens of degrees). 

Angle of impact (8): The angle measured in the 

plane of trajectory between the local horizontal 

and the path of the missile at impact (angle 

AOB). 

Kinetic energy of projectile (Ep): One-half the product of the mass and square of the velocity of the 

missile at impact. 

CRATER TERMS 

Rim diameter (Dr): The maximum distance measured across the crater along a line from one rim 

crest to the opposite rim crest or from the rim 

crest on the down-trajectory side of the crater to 

the crater edge on the up-trajectory side (where a 

rim may be absent) of the crater. 

Rim radius (rr): The sum of the rim diameter in the 

plane of the trajectory and the rim diameter 

normal to the trajectory plane divided by four. 

Apparent diameter (Da): The maximum distance 

measured across the crater along a line in the 

plane of the original ground surface from one side 

of the crater to the other. 

Apparent radius (ra): The sum of the apparent 

diameter in the plane of the trajectory and the 

apparent diameter normal to the trajectory plane 

divided by four. 

Rim height (h): The elevation of the crater rim 

above the local original ground surface. 

Average rim height (h): The average of four elevations of the crater rim above the local original 

ground surface measured in the plane of the 

trajectory and at right angles to it. 

Apparent crater depth (da): The depth of the crater 

measured from the projected original ground 

surface to the bottom of the crater. 

Apparent crater volume (Va): The volume of the 

crater below the original ground surface. 

Displaced mass (M d): The product of the original 

target density and apparent crater volume. 

DESCRIPTION OF CRATERS 

CRATER MORPHOLOGY 

Crater morphology is a function of the missile 

trajectory, crater size, target material, and slope. As a 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B5 

result of the oblique trajectories, the missile impact 

craters exhibit some bilateral symmetry about the 

plane of the trajectory (frontispiece). The average ratio 

of crater rim diameter along the trace of the missile, and 

the rim diameter perpendicular to it is 1.07 ± 0.17 (1u), 

and values of the ratio ranged from 0.87 to 1.62. The 

craters are generally elongate parallel to the plane of 

the trajectory, but a substantial number of craters are 

elongate in directions perpendicular to the trajectory. 

Typically, crater rims are low to nonexistent beneath 

the trajectory and well developed on the downtrajectory side of the crater. Mean slopes of crater walls 

beneath the trajectory are commonly steeper than those 

on the opposite wall so that, in plan view, the deepest 

part of the crater is displaced up-trajectory with respect 

to the midpoint of the apparent diameter parallel to the 

trajectory plane. Crater flanks beneath the trajectory 

are commonly at the original ground surface, those on 

the down-trajectory side slope gently away from the 

elevated crater rim. Mirror image rims, crater walls, 

and gently outward-sloping crater flanks are found in 

the lateral directions. A topographic map of a typical 

missile impact crater is shown in figure 2. 

Crater morphology changes with size. Large craters 

produced by missiles with oblique trajectories in cohesive targets tend to have elevated rims in all directions 

whereas small craters are commonly rimless beneath 

the trajectory. This tendency is well illustrated by 

craters in moist gypsum lake beds (figs. 3 and 4). Two 

small craters, 2.0-3.6 m across, are rimless on the uptrajectory side (see for example, fig. 3). All three large 

craters in the same material, 7.4 m across, have welldeveloped rims on the up-trajectory side (see for example fig. 4). Similar results are observed for impact and 

explosive craters in rock and cohesive materials. 

Centimetre- to metre-size craters in rock are rimless 

and large pie-shaped spalls are ejected from the crater 

(Moore and others, 1962; Gault and others, 1966; Horz, 

1969; Duvall and Atchison, 1957; Johnson, 1962). Large 

craters in rock, on the order of tens and hundreds of 

metres across, are surrounded by rims containing 

blocks of ejecta that are small relative to crater diameter (Nordyke and Wray, 1964; Shoemaker, 1960; 

Boutwell, 1928; Spruill and Paul, 1965). 

Physical properties of the target materials partly 

control crater morphology, particularly for small 

craters. Small craters in cohesive rock tend to be rimless, whereas those in moderately cohesive alluvium, 

colluvium, and fixed gypsum dunes have well-developed 

rims in down-trajectory directions. Craters in nearly 

cohesionless materials such as sand have continuous 

rims, best developed in the lateral and down-trajectory 

directions and weakly developed up-trajectory (fig. 5). 

Profiles of craters in more cohesive materials have steep 

B' 

A A' 

~2~2~ ~ 1 1 ~ w w 2 2 0 0 

B B' 

~:rs=z _____ ...Lt) 

0 2 4 6 METRES 

FIGURE 2.-Contour map and profiles illustrating bilateral symmetry 

oftypical crater produced by missile impact in gypsiferous alluvium 

and fixed gypsum dune. Contour interval, 0.1525 m (V2 ft). Arrow 

indicates trace ofmissile. The profile labeledB-B1 is in the plane of 

the trajectory; A-AI is perpendicular to the plane ofthe trajectory. 

Dot-dash line represents crater rim; dashed lines in profile show 

original ground surface. Note steep wall on up-trajectory crater 

wall, symmetry of crater and rims in profile A-A 1 and lack of it in 

profile B-B 1

, and bilateral symmetry of plan view. (Ep = 19.7 x 1014 

ergs, 8=45.0°. Crater 17.) 

slopes, particularly in the upper part of the crater walls 

and on the up-trajectory wall (figs. 2, 3, and 4). For less 

cohesive targets such as sand and colluvium, craters 

tend to be conical (fig. 6). Rimless to nearly rimless 

craters may result when the target is very porous and 

moderately cohesive (crater 12). Small craters less than 

about 1 m across in materials with low cohesion, such as 

sand, produced by projectile impact in the laboratory 

(Gault and others, 1966) and by chemical explosives 

with small depths of burial (Oberbeck, 1971) are 
B6 CONTRIBUTIONS TO ASTROGEOLOGY 

+ 

B' 

1.5 ·1., 

w w 

~1.0~1.0~ r r 

~ 0.5 0.5 ~ 

0 0 

B' f' 1.0 ~ 0.5 :2 

0 

0 2 METRES 

FIGURE 3.-Contour map and profiles illustrating partial rim and 

marked bilateral symmetry of small crater in gypsum lake beds 

produced by missile impact. Contour interval 0.1525 m (Vz ft). Arrow 

indicates trace of missile. The profile B-B' is in the plane of the 

trajectory, A-A' is perpendicular to the plane of the trajectory. 

Dot-dash line on map represents crater rim; dashed lines in profiles 

show original ground surface. Note asymmetry of profile B-B ', 

absence of rim on up-trajectory side of crater, and symmetry of 

profile A-A'. (Ep=5.92x 1014 ergs, 8=51.0°. Crater 11.) 

characterized by elevated continuous rims and conical 

shapes, although some have concentric structures on 

their floors (Fullmer, 1966). 

For several missile impact craters on steep slopes 

(craters 2, 9, and 58), crater rims and flanks were low to 

nonexistent on the upslope part of the crater as well as 

on the up-trajectory side, and well developed downslope. 

Slope is thus shown to affect the symmetry of the 

craters. 

MAP UNITS 

Generally, seven mappable units are exposed in and 

around the craters (fig. 7). Three of these are ejecta 

units: thick ejecta (te), thin to discontinuous ejecta (td), 

and scattered ejecta (ts). Three are target materials: 

undeformed target material (tm), tilted and broken 

target material (tb), and shattered and fractured target 

material (sf). The seventh is slope material and debris 

on the crater floor (sm). These units, for a typical crater, 

are described below. 

Thick ejecta is a blanket of debris with lobate extensions, about 5 to 30 em thick, deposited from the 

crater rim to distances of several metres with bilateral 

symmetry about the plane of the trajectory (frontispiece 

and fig. 7). Normally, it is deposited in down-trajectory 

B' 

B B' 

(j....____ -~---=----l...f:~ 0 2 4 6 8 10 METRES 

FIGURE 4.-Contour map and profiles illustrating complete rim 

around large crater in gypsum lake beds produced by a missile 

impact. Bilateral symmetry is less well developed than in smaller 

craters. Contour interval 0.1525 m (% ft). Arrow indicates trace of 

missile. The profile B-E' is in the plane of the trajectory and A-A' is 

perpendicular to the plane of the trajectory. Dot-dash line on map 

represents crater rim; dashed lines in profiles show original ground 

surface. Note difference between this crater and the small crater in 

figure 3. (Ep =23.2 x 1014 ergs, 8=46.2°. Crater 50.) 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B7 

and lateral directions and absent beneath the trajectory. It is composed of particles ranging in size from 

powder to sizeable fragments (fig. 8) that in some 

materials may be as large as % m. Most of the ejecta is 

disaggregated and fragmented target material, but as 

much as 20 to 30 percent may be sheared and 

compressed fragments of target material. Pieces of 

projectile are found in this unit. At most places, where 

the target material is layered, the sequence of the 

original layering is preserved in the ejecta but inverted 

(figs. 9 and 10). 

Thin to discontinuous ejecta (fig. 11) surrounds the 

thick ejecta and may extend a small distance in the 

up-trajectory directions. Fragments in this unit are 

generally smaller than those in the thick ejecta but 

consist of the same three types of material. Fragments 

are scattered to distances near 12 to 16m at right angles 

to the plane of the trajectory and 20 m or so in the 

forward direction when the crater diameter is near 5 to 6 

m across. At some craters small tongues of this unit 

extend short distances up-trajectory. 

Scattered ejecta (fig. 12) is gradational with thin to 

discontinuous ejecta, between it and the limit of 

throwout beyond which no fragments are found. In this 

unit, isolated fragments are found widely separated 

from one another. Where the uppermost surface of the 

target is nearly cohesionless, the fragments produce 

secondary impact craters; where the uppermost surface 

FIGURE 5.-Crater in sand produced by missile impact. Note small rim 

to upper left, up-trajectory side of crater. Crater is about 2.7 m 

across. Metal object (shown by arrow) is piece of missile. 

(Ep = 6.63x 1Q1 9 ergs, 8=51.0°. Crater 13.) Photograph courtesy of 

U.S. Army. 

B 

A' ]J 

B B' 

t-

~2t=s=zl2~ 1 1 t- w w ~ ~ 

0 0 

0 2 4 6 METRES 

FIGU RE 6.-Contour map and profiles of crater in colluvium illustrating conical shape of craters in weakly cohesive targets. Crater 

produced by missile impact. Contour interval 0.1525 m ('h ft). Arrow 

indicates trace of missile. Profile B-B' is in the plane of the 

trajectory; A-A' is perpendicular to the plane of the trajectory. 

Dot-dash line on map represents crater rim; dashed lines in profiles 

show original ground surface. Note difference in profiles for this 

crater and those in figures 2 and 4. (Ep=31.4x10 14 ergs, 8=45.0°. 

Crater 16.) 

is cohesive, only scattered fragments and debris are 

found. The limit ofthrowout from most craters is about 

130m; from some, it may be as far as 330m. Boundaries 

of the limit ofthrowout have the same type of symmetry 

as other ejecta units and extend chiefly in the downtrajectory direction (fig. 13). For some craters, scattered 

ejecta composed mainly of projectile fragments is found 

up-trajectory. · 

Undeformed target material is undeformed material 

surrounding the crater and underlying part of the ejecta. The distribution and character of other units depend 
B8 CONTRIBUTIONS TO ASTROGEOLOGY 

--

td 

A 

----ts/tm) 

--

0 5 METRES 

(\ 

I \ 

I \ 

I \ 

r.....,___ ts / tm I \ 

\\ ""'"---........ I \ 

r--'--- '--- I I 

" \ -----'--J I .......... '-...'--'--- \ ~"--'--- -"--_) r'--- I 

B 

""-.. (j te '---\ I 

" _; ....-·-·, \II "" td ('" / • '-~ ,..----_) ) Crater 

/ \ ( '· ,, ----- '--- , ,· Crater rim 

) " ·--- -~ r ...---..:::---~ I I 

0 

'---- \ \_ I ts/ tm \ I 

5 

\ I 

\ I 

\ I 

I I 

\.I 

10 METRES 

FIGURE 7.-Crater produced in fixed gypsum dune by missile impact: 

tm, target material; te, thick ejecta; td, thin to discontinuous ejecta; 

ts, scattered ejecta; tb, tilted and broken target material; sf, 

shattered and fractured target material; and sm, slope material. A , 

Detail near crater;B, Distribution of thin to discontinuous ejecta 

and thick ejecta around crater. Arrow indicates trace of missile . 

(Ep=24.1 x 1014 ergs, 8 = 45.7°. Crater 18.) 

FIGURE 8.-Thick ejecta from crater produced in dry sandy alluvium 

by missile impact. Note ejecta range in size from fine debris to 

fragments 10 or more em across. Arrow "p" points to projectile 

fragment, "c," sheared and compressed target material partly 

coated with powdered projectile, "f," relatively undeformed target 

material. (Ep=20.4x 1014 ergs, 8 = 46.4°. Crater 31.) Photograph 

courtesy of U.S. Army. 

on the characteristics of the target material summarized in the introduction. Cohesion and water content of the target material are critical. In the typical 

case, the target material was dry to moist, weakly 

cohesive silts and sands. 

Tilted and broken target material underlies the thick 

ejecta below the rim and beneath the flanks (fig. 9). Here 

target material is warped upward and fractured. Rotation and upward warping rapidly decrease outward 

from the rim crest. Generally, upward warping of the 

target material is absent on the up-trajectory side. 

Tilted and broken target material is generally exposed 

3 

------- -------

0 2 METRES 

1. Ejecta, lower horizon 

2. Ejecta, upper horizon 

3. Tilted upper horizon 

4. Tilted lower horizon 

5. Slope material 

FIGURE 9.- Profile through down-trajectory flank of crater in alluvium produced by missile impact showing inverted stratigraphy. 

Note lower horizon unit of ejecta (l) overlies upper horizon unit of 

ejecta a lthough it was originally stratigraphically lower. Original 

ground surface was tilted upward and broken near crater. 

(Ep=13.8x10 14 ergs, 8=46.4°. Crater 6.) 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B9 

FIGURE 10.- Target materials in inverted sequence exposed in upper 

crater wall of crater in water-saturated gypsum lake beds. Darker 

gray ejecta overlies lighter red-brown ejecta; red-brown unit overlies gray unit in undisturbed target material. (Ep=15.7x 1014 ergs, 

8 = 45.9°. Crater 7.) Photograph courtesy of U.S. Army. 

along the upper crater walls in the lateral- and downtrajectory directions and, rarely, on the flanks. 

Shattered and fractured target material (fig. 14) is 

exposed on the steep crater wall and edge beneath the 

trajectory. Open fractures concentric to the crater edge 

and even downward faulting occur near the crater edge. 

This unit may include material with closely spaced 

conjugate fractures showing sheared surfaces and 

coatings of powdered projectile. 

Slope material is composed of cohesionless debris at or 

below the angle of repose within the crater and debris on 

the crater floor. Some of this material is the result of 

fallback of ejecta, some the result of slumping. Pieces of 

FIGURE 11.-Thin to discontinuous ejecta around crater in silty alluvium produced by missile impact. Pick is 30.5 em long. Note finer 

ejecta between fragments. (Ep = 24.1 x 10l4ergs, 8=45.7°. Crater 15. 

Photograph courtesy of U.S. Army. 

FIGURE 12.--Scattered ejecta from crater in clayey silt and silty clay. 

Ejected fragments have produced secondary impact craters in moist 

ripple-marked sand. (Crater 20.) Photograph courtesyofU.S. Army. 

broken target material, sheared and compressed 

material, and the projectile are found in this unit. Slope 

material is best developed on lower parts of crater walls, 

especially down-trajectory, and lateral walls. 

DISTRIBUTION 

Variations in the distribution and character of the 

map units described are a function of target material 

and crater size. When the target material is alluvium, 

--------.......... I / /- -~ .::::-=--==----- / 1 Crater ... _..·, -.., ---

/ I -· I .......__.......__ 

/ \ /1 -....___ 

'; td ..- - - ) 

I I--... I ( I '"' , _, 

I " \ 

I " \ I \ 

I \ 

I ) 

\ ( \ Limit of throwout __,..J 

\ I 

\ " I 

\.....___ // 

-....___ /''....._/ 

I ____..------\ / I .------ J l.--------

0 100 200M ET RES 

FIGURE 13.- Map illustrating limit ofthrowout and scattered ejecta, 

extending 330 m from crater produced in clayey silt by missile 

impact. Arrow indicates trace of missile. (Ep =25.2x 1014 ergs, 

8=25.8°. Crater 20.) 
BlO CONTRIBUTIONS TO ASTROGEOLOGY 

FIGURE 14.- Shattered and fractured target material exposed on uptrajectory wall of crater in dry silty sand. Note conjugate fractures 

producing diamond-shaped pattern; some of the fractures are coated 

with projectile material. Tensile fractures mainly parallel to plane 

of photograph, formed later and do not have coatings. Scale is about 

16 em long. (Ep=69.9x 1014 ergs, 8=40.6°. Crater 53.) Photograph 

courtesy of U.S. Army. 

colluvium, fixed gypsum dunes, and rock, thick ejecta is 

absent in the up-trajectory direction. Aprons of thick 

ejecta on the down-trajectory side of the crater (fig. 15A) 

are common and many craters have concentrations of 

ejecta that form lobes in lateral directions (fig. 15B). In 

some cases, more debris is found in lateral directions 

than in the down-trajectory direction (fig. 15C). Around 

some craters, isolated islands of thick ejecta are found 

beyond a main layer of thick ejecta. Thick ejecta completely surrounds craters in water-saturated gypsum 

lake beds and large craters in moist gypsum lake beds. 

At these craters, such ejecta is thicker and extends 

farther in the lateral and down-trajectory directions 

than in the up-trajectory direction, with one exception. 

At crater number 44, in a water-saturated lake bed, 

thick ejecta actually extended farther up-trajectory 

than down-trajectory and laterally. Craters in weakly 

cohesive sand are characterized by small amounts of 

FIGURE 15.-Variations in ejecta distribution around craters in fixed 

gypsum dunes. A, Apron of very light ejecta parallel to trajectory 

plane on down-trajectory side. Diffuse light material alined 45° to 

trajectory trace is windblown ejecta. White panel on up-trajectory 

side is 15.2 m long and parallel to trace of missile (Crater37). B , 

Bilateral symmetry of ejecta with radial extensions of ejecta in 

lateral and down-trajectory directions (Crater 18, see also fig. 7). 

Trace of missile is from top of photograph to crater. C, Ejecta developed chiefly in lateral directions without bilateral symmetry. 

Trace of missile is from top of photograph to crater. Note maximum 

. extent of ejecta is in lateral directions and more extensive to left 

than to right (Crater 30). Photograph taken by NASA Remote 

Sensing Aircraft. 

thick ejecta in the up-trajectory direction (fig. 5). 

For layered targets, materials ejected from both 

upper and lower layers retain some discernible layer 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH Bll 

coherence in their distribution; ejecta falls in a bilaterally symmetrical pattern, and original stratigraphic 

relations are inverted. This is shown by a crater in a 

layered target of gypsiferous lake beds overlain by 

alluvium (fig. 16A). Material from the lower white 

gypsum layer is concentrated in the down-trajectory 

direction where it overlies the darker ejecta from the 

upper layers. In lateral directions little or no white 

gypsum is found superposed on the darker alluvium 

from the upper layers. A similar effect can be seen at a 

crater in silty sand and sandy silt, where dark-reddish 

materials from the upper layers are found on the uptrajectory side of the crater and materials from the 

lower reddish-gray layers are found in down-trajectory 

and lateral directions. When the gypsum layer is deep 

relative to the crater diameter, isolated patches of white 

gypsum are found near the crater rim and superposed on 

ejected alluvium from the upper layers (fig. 16B). 

Variations in distribution patterns of thin to discontinuous ejecta are similar to those in thick ejecta but 

differ in these respects: the distribution of thin to 

discontinuous ejecta may be greatly affected by the 

wind; deposition of debris is more common in the uptrajectory direction; and the outer boundary of the 

thin-ejecta units tends to be more irregular, with 

fingerlike extensions. Craters in dry to moist targets of 

alluvium, colluvium, fixed gypsum dunes, and rock 

have the least amount of thin to discontinuous ejecta 

up-trajectory; craters in water-saturated gypsum lake 

beds and large craters in moist gypsum lake beds have 

somewhat larger amounts of debris up-trajectory. 

Scattered ejecta and the limit of throwout are controlled by target material, static atmosphere, and wind. 

The static atmosphere decelerates fine-grained ejected 

debris more than coarse ejected debris; the grain size of 

ejecta depends on the cohesion of the target material. 

Deceleration by the atmosphere may be illustrated by 

comparing craters in fixed gypsum dunes, where 

fragments in the scattered ejecta are centimetre size 

and less, with craters in clayey silt, where scattered 

ejecta fragments are 15 em and less. For gypsum, the 

limit ofthrowout is near 100m or so, and for clayey silt, 

near 330m. Wind can greatly affect the scatter of ejecta. 

When the craters shown in figures 15B and 15C were 

formed, there was little or no wind, but, at the crater of 

15A, the wind distributed the ejecta along a path about 

45° to the trace of the missile. For craters in clayey silt 

with coarse ejecta, the limit of throwout and scattered 

ejecta may be skewed in the direction of the wind. 

SECONDARY IMPACTS 

Cratering by impact of ejected debris produced by 

missile impact is a function of the mechanical properties 

FIGURE 16.- Ejecta from craters in layered targets. Arrows indicate 

craters and traces of missiles. A, Crater in gypsum overlain by 0.6 m 

of alluvium. Light eject a from lower layer superposed on darker 

ejecta from upper layers with bilateral symmetry. Ejecta from lower 

gypsum layer is displaced down-trajectory with respect to ejecta 

from overlying darker alluvium. Original gypsum layer can be seen 

in crater (Crater 36, about 5 m across). B, Crater in gypsum overlain 

by 1.0 m of alluvium. Scattered light ejecta of gypsum from lower 

layer superposed on darker ejecta from lower layer. Gypsum ejecta 

is spotty because of greater thickness of overlying alluvium (Crater 

35, about 5 m across). Photograph taken by NASA Remote Sensing 

Aircraft. 
B12 CONTRIBUTIONS TO ASTROGEOLOGY 

of the near-surface materials, the character of the ejecta, and distance from the crater. A great number of 

secondary impact craters are produced by ejected debris 

where surface materials, such as sand, have low 

cohesion. Where near-surface materials are strong and 

more cohesive, no secondary impact craters are produced; rather, the surface is littered with scattered 

fragments and blocks, and piles of fine debris. Large 

secondary impact craters are produced when fragmentation of the target results in large blocks and clods. 

Where ejected debris is fine, as from craters in weakly 

cohesive sand, small secondary craters are produced. 

Secondary impact craters tend to be larger relative to 

the size of the ejected fragment at greater distances 

from the crater because the velocities, and therefore 

specific energies, are greater. 

Where secondary craters are produced by debris 

ejected from craters produced by oblique impacts, their 

distribution is bilaterally symmetrical about the plane 

of the trajectory, and each secondary crater may be 

bilaterally symmetrical about the plane of the oblique 

trajectory of the ejected fragment that produced it. 

Well-developed secondary impact phenomena were 

studied at a crater (Crater 7) produced in watersaturated gypsum lake beds where ejecta characteristics and surface properties were favorable. The surface 

layering, from the top down, is 9-12 em of cohesionless 

gypsum sand, 40 em of very pale red-brown, moist, 

cohesive gypsum and gray cohesive water-saturated 

gypsum lake beds of unknown thickness. The impact 

(fig. 10) ejected large and small fragments from the 

cohesive gypsum layers. These fragments impacted the 

ejecta from the crater as well as the surrounding 

cohesionless gypsum sand at the surface. Mapping 

revealed the presence of map units common to other 

missile impact craters (fig. 17). Thick ejecta and thin to 

discontinuous ejecta mapped completely around the rim 

and both were bilaterally symmetrical across the plane 

of the trajectory. Secondary impact craters were found 

throughout these units but were most abundant in the 

region of the scattered ejecta where their distribution 

was bilaterally symmetrical. The greatest number were 

found in down-trajectory and lateral directions. Locally, 

the secondary craters formed arcuate patterns, clusters, 

and linear arrays radial to the crater. Relative sizes of 

secondary craters and the fragments that produced 

them varied systematically, but not regularly, with 

distance from the crater. Near the crater rim, in thick 

ejecta, essentially undeformed ejected fragments were 

larger than the craters they occupied (see blocks on 

crater rim in fig. 10). Others, farther out, were the same 

size as the crater they produced and deformed so they 

filled the secondary crater (fig. 18). Many of the 

fragments were smaller than the crater, deformed, and 

lined the crater they produced (fig. 19); others were less 

deformed (fig. 20). Fragments producing the secondary 

craters are partially (fig. 21) to completely ejected. 

Commonly, each secondary crater shows bilateral 

symmetry across the plane of the trajectory of the 

secondary fragment, as at the crater of figure 22, where 

cohesive fragments impacted ripple-marked sand. Like 

the parent missile impact crater the secondary produced 

little or no ejecta up-trajectory; ejecta from it is found in 

lateral and down-trajectory directions. As this crater 

was produced in moist sand, the ejecta is composed of 

lumps scattered along radials from the crater. At the 

crater shown in figure 21, produced in dry gypsum sand, 

the ejecta forms a smooth light-gray apron on the 

down-trajectory side. Not all secondaries produced show 

such perfect symmetry. At some, the rotational energy 

of ejected fragments has caused a variety of results, 

including chains of pits where the fragment rolled and 

bo~nced, and ejected debris that is nonradial to the 

primary crater. 

Fine ejecta from craters may produce many small 

craters (fig. 23) with a wide range of sizes. A multitude 

of secondary craters produced in sand by ejecta from a 

crater in sand may all be nearly the same size and cover 

the surface, resembling raindrop impressions. When 

the surface is hard, no secondaries are produced. 

Rather, piles of debris (fig. 24) and scattered fragments 

litter the surface. DEFORMATION 

Degree of deformation of both the missile and target 

varies mainly with the velocity of the missile at impact. 

Other variables affecting deformation of the missile and 

target are density of the missile and its components, 

design and strength of the missile and its components, 

size of the missile, and shape and orientation and 

trajectory at impact. At the highest velocities, destruction of the missile is so complete that it is difficult, 

if not impossible, to find pieces of it anywhere. At lower 

velocities, large warped and bent sections of the missile 

are scattered in the ejecta or buried along with fragments, wires, nuts, and bolts. Target properties such as 

density, cohesion, angle of internal friction, grain size, 

porosity, and pore fluids affect deformation mainly of 

the target. As response of the target depends on target 

material as well as missile velocity, deformations for 

craters differ in rock, alluvium, water-saturated lake 

beds, and sand. For the typical case, the deformation 

observed in the target material is of many kinds: 

compression, shearing, mixing of missile and target 

pieces, injections, banding, fracturing, and folding result from the shock and stress waves generated by the 

impact. A typical generalized case is described below. 

Evidence for the wide range of types of deformation is 

found in ejecta from craters in moderately cohesive, 
'o 

MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH 

Cluster of 

secondary----.() a 

CraterS oO 

0 • 

0 0 

0 

,. 

~· 

Linear array 

of secondary ----._ 

craters o o o 0 0 

0 

00 

o' 

0 

0 

0 0 

0 ...-Loop of secondary craters 

0 

..... , 0 

.. .. 

0 

ts/ tm 

0 

... 

ts/tm 

• •0 

ts/ tm 

10 

-. 

0 

20 30 40 

0 

0. 

0 0 

0 

0 

50 METRES 

.. 

o. 

0 0 

B13 

FIGURE 17.-Map of crater in water-saturated gypsum lake bed showing distribution of secondary impacts, thin to discontinuous ejecta, 

and thick ejecta. Crater rim shown by solid line; te-thick ejecta, td-thin to discontinuous ejecta, ts/tm- scattered ejecta on target 

material, sma ll open circles-secondary impacts. Note concentration of secondary impacts in down-trajectory and lateral directions. 

Secondaries form linear arrays, local loops, and clusters. Arrow indic ates trace of missile. (Crater 7; see also fig. 10.) 

porous (density = L6g;l cm3 ), dry to moist target I may equal or exceed the density of the target material, 

materials where densities of some ejected fragments and small partly fused pieces of missile are scattered in 
B14 CONTRIBUTIONS TO ASTROGEOLOGY 

FIGURE 18.-Secondary crater filled by ejecta that produced it. Deformed fragment in crater is from lower gray layer. Pick is 30.5 em 

long. (Ejecta from Crater 7.) Photograph courtesy of U.S. Army. 

the ejecta along with contorted missile pieces. Some 

larger fragments of missile that failed by shearing are 

found. Shocked and deformed target materials are 

represented by sheared and compressed target material 

with dark-gray coatings of the fused and powdered 

missile (fig. 25A,B). Some sheared and compressed 

fragments have been compressed to densities as great as 

...... • • t 

.. _.,f.·' ,. ·:. 

FIGURE 19.-Secondary impacts beyond thin to discontinuous ejecta. 

Secondary craters are larger than fragments that produced them. 

Secondary projectiles from dark-gray layer of wet gypsum have 

deformed floors of secondary craters and line them. Pick is 30.5 em 

long. (Ejecta from Crater 7.) Photograph courtesy of U.S. Army. 

FIGURE 20.--Secondary craters produced by ejecta from red-brown 

layer in thin to discontinuous ejecta. Craters are larger than 

fragment that produced them. Fragment to left partly deformed, 

one to right deformed and broken. Pick is 30.5 em long. (Ejecta from 

Crater 7 .) Photograph courtesy of U.S. Army. 

2.2 g/cm3 and their surfaces are grooved and striated. 

Dark coatings of powdered and partly fused missile 

partly cover the grooved surfaces of many of these 

compressed fragments and fractures within them may 

be filled with powdered projectile. Many of them compressed, then failed in tension, as indicated by open 

fractures with hackly surfaces normal to the striated 

surfaces (fig. 25C). These coated compressed fragments 

are found in all map units from the crater floor to the 

limit ofthrowout. More intensely shocked material may 

be present in very fine debris wafted away by gentle 

winds or lost by dilution in the large quantities of other 

ejecta and materials surrounding the crater. 

Much of the target material and projectile is pulverized and fragmented to sizes of 70 em across and less 

for the target and 10 em across and less for the projectile. 

Densities of ejected fragments range from more dense to 

less dense than the original target material. Pulverized 

and disaggregated debris have densities equal to the 

grain density of the target material. Most of the ejecta is 

relatively undeformed and has about the same density 

as the target material. Large blocks and fragments of 

relatively undeformed target material are concentrated 

near the rim of the crater, in slope material, and in thick 

ejecta, but are found in other map units farther from the 

crater, where they tend to be smaller. Fragments of this 

type are bounded by irregular, hackly surfaces, joint 

surfaces, the original ground surface, and, when pres-
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B15 

FIGURE 21.- Secondary crater produced by fragment from gray layer. 

Secondary fragment is broken into pieces, deformed, and ejected 

from crater. Ruler, about 16 em long, is on up-trajectory side. Light 

rim of crater is ejecta from lower gypsum sand superposed on darker 

materials of surface. (Ejecta from Crater 7 .) Photograph courtesy of 

U.S. Army. 

ent, bedding planes. They may be rectangular to irregular in shape. Relatively undeformed fragments are 

products oflate-stage ejection where normal stresses in 

the shock wave and subsequent stress waves have 

FIGURE 22.-Secondary craters produced by ejecta in moist ripplemarked sand. Handle of pick points up-trajectory. Note concentration of ejecta in lateral and down-trajectory directions and virtual 

absence up-trajectory. Tertiary ejecta is lumpy because sand was 

moist. (Ejecta from Crater 20.) Photograph courtesy of U.S. Army. 

FIGURE 23.-Secondary craters produced by fine ejecta impacting 

cohesionless gypsum sand. Ruler is approximately 16 em long; pick 

is 30.5 em long. Ejecta from crater is moist gypsum lake beds. Lake 

beds overlain by 9 em of dry gypsum sand. (Ejecta from Crater 11.) 

Photograph courtesy of U.S. Army. 

dropped to values near and less than ambient conditions. They have failed in tension, forming new fractures, separating along preexisting fractures, or 

separating along bedding planes. 

Parts of the missile have failed in tension. Occasionally nuts, bolts, and other components are found, showing preexisting boundaries controlled the manner in 

which they failed. Some small pieces of relatively 

undeformed missile are broken and partly to completely 

separated along hackly irregular fracture surfaces, 

suggesting tensile failure. 

Beneath the ejecta the original ground surface is 

tilted away from the crater on the lateral and downtrajectory flanks of the crater. At some craters, layers at 

and near the ground surface can be traced craterward to 

the rim, then outward, overturned and superposed on 

themselves. Most commonly, overturned and jumbled 

blocks from the near surface rest upon the original 

ground surface and bury it. The original surface on the 

up-trajectory flank is generally exposed. Here the surface is level or eyen displaced downward, and open 

concentric fractures and faults occur. at right angles to 

the surface. 
B16 CONTRIBUTIONS TO ASTROGEOLOGY 

FIGURE 24.- Pile of debris and scattered fragments from crater in 

gypsiferous alluvium. Surface materials were so cohesive that no 

secondary craters formed. Pick is 30.5 em long. (Ejecta from Crater 

15.) Photograph courtesy of U.S. Army. 

ZONES OF SUBSURFACE DEFORMATION 

Studies of trenches through four craters indicate that 

the subsurface deformation can be classified into five 

zones (see for example, figs. 26 and 27): (1) mixed breccia, (2) sanded material, (3) a zone of conjugate fractures, (4) tilted and broken material, and (5) a zone of 

open fractures. 

MIXED BRECCIA 

Mixed breccia forms a lens composed of fragments of 

missile and compressed target material in a matrix of 

fine debris beneath the crater floor. The fragments are 

jumbled and no simple pattern can be seen. Surfaces of 

adjacent large fragments are rarely parallel. Fragments of both the compressed target material and missile are as large as 15 em, but generally smaller. Many 

surfaces of the compressed target material are polished, 

striated, and grooved, showing that they have been 

sheared. Mixed breccia (fig. 28) is found below the center 

ofthe crater floor. Diameters ofthe mixed breccia bodies 

beneath the craters in alluvium with an underlayer of 

gypsum measure 1.2 to 1.5 m across where exposed; 

those in indurated gypsum dunes measure 2.1 to 2.3 m 

across. Boundaries of mixed breccia with adjacent units 

FIGURE 25.-Sheared and compressed target material and coated 

rocks. A , Sheared and compressed target material ejected from 

crater in colluvium. Note grooves and striations on lower surface of 

fragment (from Crater 16.) B, Coated fragment from crater in colluvium. Coating indicated by arrow is black and composed chiefly of 

powdered, fragmented, and fused projectile (from Crater 58.) 

Photography courtesy of U.S. Army. C, Sheared and compressed 

target material with grooves and striations on surfaces. Note open 

tension fractures transecting shear surfaces at right angles. Target 

was gypsiferous alluvium (from Crater 15.) 

are gradational; a few distinct stringers of mixed breccia containing pieces of projectile penetrate the sanded 

material (fig. 29). 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B17 

Evidence of displacement of materials of the mixed 

breccia is ample. Fragments of sheared and compressed 

materials identical with those ofthe mixed breccia are 

found in ejecta and slope material along with pieces of 

the missile. Although the sheared and compressed 

target material is found chiefly in the mixed breccia and 

thick ejecta, scattered small fragments are found uptrajectory and in the thin to discontinuous ejecta. 

SANDED MATERI AL 

Sanded material (fig. 30) is well developed only in 

craters in indurated gypsum. It is composed of disaggregated gypsum and small lumps of material that 

can be easily broken by finger pressure. No evidence of 

compression is found in the sanded zone and pieces of 

missile found appear to be cataclastic injections. Banding is developed in the sanded material near the contact 

with the mixed breccia, where bands are subparallel to 

the contact. Toward the zone of conjugate fractures, the 

banding is less distinct and the frequency of small 

lumps increases laterally. This unit, where exposed, 

surrounds the mixed breccia on all but the up-trajectory 

side; its symmetry is bilateral across the plane of the 

trajectory. 

As the sanded material is banded subparallel to the 

adjacent contacts and has the same sense of symmetry 

as the ejecta, it represents fabric resulting from the flow 

of debris near the final stage of the ejection process. 

ZONE OF CONJ UGATE FRA CTURES 

The zone of conjugate fractures (fig. 31) is characterized by a crisscross fracture pattern. This pattern is 

closely spaced near the sanded zone, where fracture 

frequencies are about 0.8 to 1.2 per linear centimetre; 

frequencies decrease outward to about 0.3 per linear 

centimetre and less, at the boundary of the unit. Near 

the contact with sanded material, acute angles between 

fractures appear to be larger (near 70° to 60°) than those 

(near 60° to 50°) about a metre from the boundary. 

Although the two fracture sets normally show no relative displacement, they are locally offset a fraction of a 

centimetre or so along one fracture plane or the other. 

Such offsets, which suggest a shearing motion, are most 

frequent near the sanded zone boundary. The whole 

fracture pattern is flexed upward below the crater rim, 

where individual fracture planes can be followed along 

their curving traces. 

Exposures of the zone of conjugate fracturing encircle 

the mixed breccia and sanded material. For craters in 

indurated gypsum dunes, such fracture zones are about 

6.1 m across. For one of the craters produced in 

alluvium, it is about 4.6 m across, for the fourth crater 

we trenched it is poorly defined. 

FIGURE 26.- Crater in indurated gypsum dunes produced by missile 

impact. Cross section shown in figure 27. Arrow indicates trace of 

missile. Note absence of ejecta on up-trajectory side, bilateral 

symmetry of ejecta, and large blocks ofundeformed target material 

up to 0.46 m across. (Ep = 16.0 x 1015 ergs, 8=47.0° degrees, Crater 

40, rim diameter about 5.6 m.) Photograph courtesy of U.S. Army. 

TILTED AND BROKEN MATERIAL 

In the tilted and broken material (fig. 32), widely 

spaced open fractures, some parallel to the ground 

surface and some perpendicular to it, form large blocks. 

The blocks, which are formed by tensile failure, are 

devoid of internal conjugate fractures and are themselves undeformed. Blocks of tilted and broken material, unlike lumps and pieces from the sanded material 

and zone of conjugate fractures, can be broken only with 

difficulty. Beneath the crater rim, the blocks and their 

bounding fractures have been rotated upward. In some, 

bands and layers can be traced from the tilted and broken zone as a continuous fold that overturns and 

continues in the ejecta. 

The lateral extent of tilted and broken material is 

difficult to establish visually, but studies of similar 

craters in identical materials, using an engineering 

seismograph with a 3.05-m geophone-source spacing, 

indicate a significant change in acoustic velocities of 

indurated gypsum at distances between 5.5 and 8.9 m 

from the crater center for radials perpendicular to the 

trajectory planes; for radials down-trajectory within a 

metre of the crater rim, acoustic velocities have decreased to less than a third or a fourth of that of the 

undisturbed gypsum (fig. 33). ·Significant disruption of 

the materials to distances of nearly 3 to 4 crater radii is 
B18 CONTRIBUTIONS TO ASTROGEOLOGY 

(Jl 

w 

a: 

fw 

~ 

3 

2 

3 

2 

(/) 

w 

a: 

fw 

~ 

L-------------------------------------------------------------------------------------~ 0 

0 2 3 METRES 

EXPLANATION 

D 

Talus and fallback Sanded material Open-fracture zone 

Cataclastic injection 

Thick ejecta Conjugate-fracture zone 

Mixed breccia Tilted, broken material Open fracture 

FIGURE 27.-Cross section of Crater 40 parallel to plane of trajectory showing subsurface deformation zones: mixed breccia, sanded 

material, zone of conjugate fractures, tilted and broken material, and zone of open fractures. 

produced by the impact. No such clear change of acoustic velocity is found around the craters in alluvium, 

which had initially low acoustic velocities (Hans 

Ackerman, oral commun., 1969). It was possible to detect disruption of the material with other techniques. 

Strengths measured with a 3.8-cm-diameter shear vane 

were found to decrease toward the crater rim. Similar 

results were obtained with shear vanes and penetrometers around a crater in sandy silts and silty sands, 

shown in figure 34. Here again, little change is noted for 

craters in initially weak materials. 

ZONE OF OPEN FRACTURES 

The zone of open fractures (fig. 35) differs from tilted 

and broken material in that the original ground surface 

is often exposed and the original surface is level or 

displaced downward. Sparse, nearly vertical open 

fractures in the zone are concentric to the crater edge 

and confined to the up-trajectory side of the crater. 

Beneath the surface, shattered target material or 

conjugate fractures forming crisscross patterns are 

exposed on the up-trajectory crater wall (fig. 13). The 

conjugate fractures and tensile fractures perpendicular 

to them form diamond-shaped blocks with acute angles 

pointing upward and downward. Some of the conjugate 

fractures are grooved, striated, and coated with powdered projectile, whereas the tensile fractures are 

hackly and uncoated. 

Layering provided a datum for tracing displacements 

of subsurface materials in the target material of two 

craters in silt (figs. 36, 16), Craters 35 and 36. In both 

craters, a layer of white gypsiferous silt was overlain by 

reddish-brown silty alluvium. The depth to the gypsiferous silt was 0.6 m (relatively shallow) for one (fig. 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B19 

FIGURE 28.-Mixed breccia below crater floor. Dark fragments are 

pieces of missile. Note gray surfaces of some sheared and compressed gypsum, coated with thin layers of powdered missile. Rule is 

0.305 m (12 in.) long. (Crater 40; see also fig. 26.) Photograph 

courtesy of U.S. Army. 

36A,B), and about 1.0 m for the other (fig. 36C). For the 

first crater, the gypsiferous layer on the up-trajectory 

side was not displaced, and could be traced through a 

zone of intensive fracturing (zone of conjugate fractures) 

to the talus and fallback (fig. 36A). On the downtrajectory and lateral sides, the gypsiferous layer was 

folded and displaced upward (fig. 36A,B). A mixed 

breccia of gypsiferous silt and an intensely fractured 

zone were found beneath the crater floor. For the second 

0 2cm 

FIGURE 29.-Cataclastic injection of mixture of projectile and gypsum 

fragments into sanded zone. Injected unit is gray; sanded unit is 

white. Black fragments in injected unit are pieces of projectile; 

white fragments are gypsum; gray matrix is mixture of powdered 

projectile and sand-size grains of gypsum. 

FIGURE 30.--Sanded material and banding. Conjugate fracture zone is 

toward left, mixed breccia and crater toward right. Rule is 0.305 m 

(12 in.) long. (Crater 40; see also fig. 26.) Photograph courtesy of 

U.S. Army. 

crater, the deeper gypsiferous layer was displaced 

downward on the up-trajectory side and could be traced 

inward toward the center, where it was truncated. On 

the down-trajectory side, the gypsiferous layer, though 

FIGURE 31.-Conjugate fractures. Sanded material (not shown) to left. 

Rule is 0.305 m(12 in.) long. (Crater 40; see also fig. 22.) Photograph 

courtesy of U.S. Army. 
B20 CONTRIBUTIONS TO ASTROGEOLOGY 

FIGURE 32.-Tilted and broken material exposed in upper wall of 

crater. One tilted and broken block indicated by arrow. Lower slope 

of crater wall is covered by talus (Crater 17). Photograph courtesy of 

U.S. Army. 

brecciated, could be traced to the mixed breccia (fig. 

36C). Here the mixed breccia, composed of sheared and 

compressed gypsum and pieces of missile, was displaced 

above the original horizon of the gypsiferous layer. Little or no gypsum was visible on the crater floor or walls 

prior to excavation, although some was present in the 

ejecta (fig. 16). 

Although only four craters in fixed gypsum dunes and 

alluvium were trenched, the character of ejecta and 

craters indicate that significant variations in styles of 

deformation occur with target material. The variations 

are particularly marked for craters in rock, sandcolluvium, very low density alluvium, and watersaturated gypsum lake beds. Ejecta from impact craters 

in rock with initial densities as great as 2.6 g/cm3 are 

composed of rock fragments, crushed rock, and pieces of 

deformed missile. There is no evidence for compression 

of target materials and subsurface deformation like 

that described above, or penetration of missile parts 

beneath the surface. Indeed, some craters produced in 

limestone are small and remarkably shallow (fig. 37). 

Craters in weakly cohesive sand and colluvium do not 

produce the large undeformed blocks characteristic of 

craters in more cohesive materials such as fixed gypsum 

dunes. Rather, the largest ejecta fragments are compressed and sheared target material, and most of the 

ejecta is undeformed sand or colluvial debris. The 

deformed or fragmented missile may be completely 

ejected or may remain partly below the surface, depending on impact velocity and angle of impact. When 

the target material has a low density, the amount of 

ejecta is small, and it contains no compressed target 

material or missile parts. These materials remained 

below the surface. 

1000 u 

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METRES 

EXPLANATION 

0 Down-t rajectory radia l 

e L ateral rad ial 

FIGURE 33.- Seismic velocities as a function of distance from crater 

rim. Open circles, velocities along a radial on down-trajectory flank; 

filled circles, velocities along a radial in lateral direction. Target 

was indurated gypsum dune. Geophone-source spacing, 3.05 m (10 

ft). Note decrease in seismic velocity with decreasing distance from 

crater rim. (Craters 28, 29, and 30.) 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B21 

The two craters in water-saturated gypsum lake beds 

differ from typical craters in two respects. First, ejecta 

from them contained no sheared and compressed target 

material; rather, many of the ejected fragments were 

essentially uncompressed or possibly dilated. Such a 

result might be expected because the pores of the lake 

beds were filled with water. Missile pieces were found 

outside one crater (Crater 7); none were found around 

the other (Crater 44). Second, the lake beds were 

layered such that deformation below the rims could be 

recognized and carefully traced. In both cases, the 

original beds were tilted upward on all crater sides. At 

the down-trajectory side of Crater 7 (fig. 38), a small 

white gypsum layer could be traced craterward from its 

original position below the surface where it steepened 

near the rim, overturned, and became part of the ejected 

flap. Up-trajectory, no layers could be traced continually, although the stratigraphic sequence in the ejecta 

was inverted. At Crater 44, folding and overturning 

below the rim was more complex and two layers formed 

a complex overturned syncline (fig. 38B). 

Reasonable estimates of missile and target deformation can be made as a function of velocity of the 

missile at impact and density of the target, although 

there are other less important variables. Qualitatively, 

the importance of velocity in missile deformation results from the fact that the specific energy of the missile 

is proportional to the square of the velocity at impact. 

The importance of density results from a general 

12 

J<... Up-trajectory 

10 I \ 

I \ EXPLANATION 

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2 I .--1!/ 30cm /I p- -~"- <Y' 30cm 

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0 

6 4 2 0 2 4 6 8 10 

RADIAL DISTA NCE . IN METRES 

FIG URE 34.-Shear-vane measurement(s) for crater in fine silty sand 

and sandy silt along down-trajectory, lateral, and up-trajectory 

radial directions at various depths. Numbers indicate depth of 

measurement. Note large decrease of shear vane measurements 

near crater rim for lateral and down-trajectory sides. Change of 

shear-vane measurements not clearly correlated with distance from 

crater edge on up-trajectory edge. (Crater 24; see also frontispiece .) 

; 

. . .: •' .·) 

:·.J 

) • *~ 

•;.J :.· - _; 

. •' ' .. ./ / .__ 

~ '· 

FIGURE 35.-0pen fracture near up-trajectory edge of crater to right. 

Surface between open fracture and crater wall displaced downward 

(Crater 17). Photograph courtesy of U.S. Army. 

correspondence of rock strength and density and hence 

deceleration of the missile at impact. Subsurface deformation ofthe target and the distribution of deformed 

material are strongly dependent on these variables. The 

degree of deformation of the missile is chiefly a function 

of its velocity and can be approximately classified into 

six groups (fig. 39): (1) bending the missile and stripping 

of appendages such as fins, (2) rupture ofthe missile and 

extensive internal damage to components, (3) rupture 

of missile, components, and spillage of the contained 

parts, (4) fragmentation ofthe missile and components 

into separate scattered contorted pieces, (5) powdering, 

fragmentation into pieces 10 or 15 em across and less, 

partial melting, and partial to complete ejection of 

powder and pieces, and (6) powdering, fragmentation of 

missile into pieces a few millimetres across and less, 

partial melting, and ejection of all or most ofthe missile 

and its components. With each successive stage, it 

becomes increasingly difficult to find identifiable pieces 

of missile. At the highest velocities, the only identifiable 

remnants of the missile are dark gray coatings on 

fracture surfaces. The missile or pieces of it may be 

found at the surface, partly buried, or completely 
B22 

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CONTRIBUTIONS TO ASTROGEOLOGY 

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Talus and fallback 

2 

Thick ejecta 

Mixed breccia 

gypsiferous silt 

EXPLANATION 

Fractured 

and brecciated 

gypsiferous silt 

0 2 

Silty alluvium 

Gypsum layer 

Gypsiferous 

silt 

3 MET RES 

B 

0 2 M ETRES 

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EXPLANATION 

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Mixed breccia Fractured silty Fractured Brecciated Brecciated 

of gypsum layer alluvium gypsum layer silty alluvium gypsum laye r 

(/) 

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MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B23 

FIGURE 37.-Missile impact craters in rock. Craters are about 1.0 m 

across, less than 0.35 m deep. (Ep= 2.9 x 1016 ergs, 8 = 54°,Craters 22 

and 23.) Photograph courtesy of U.S. Army. 

buried. Estimated missile deformation and degree of 

burial are shown relative to density of target material 

in (fig. 39). 

FIGURE 36.-Cross sections through craters, parallel and at right 

angles to plane of trajectory. A, Cross section through crater parallel to plane of trajectory showing mixed breccia and deformation of 

gypsum layer. Note gypsiferous layer is not displaced on uptrajectory side and is folded upward on down-trajectory side. (Crater 

36; fig. 16.) B, Cross section through rim in lateral direction. Note 

gypsiferous layer is folded upward (Crater 35). C, Cross section 

through crater parallel to plane of trajectory showing mixed breccia 

composed chiefly of gypsum from gypsiferous layer (sheared and 

compressed) displaced upward above the horizon of the original 

layer. Gypsiferous layer on up-trajectory side has been fractured, 

brecciated, and displaced downward. 

Overturned 

Ground surface 

~~~==~-~~~~~===~~~ ~~~~~~~~~~~~ ~~~ - - - Red-brown 

Gray 

0 2 3 4 

Gypsum ejecta 

and fallback(?) 

C~"?'~~~j/Mediu -b rown sand 

.....,..-.._'--'--""-'-r--Ground surface 

/iTiii/i7;7~~=-:.J- Dark brown silt 

Green clay 

Gypsum sand 

Gray clay 

0 2 

5 METRES 

3 METRES 

FIGURE 38.-Cross section showing structures observed in rims of 

craters in water-saturated gypsum lake beds. A, Simple overturned 

syncline on down-trajectory side. Crater is to right (Crater7). B, 

Complex overturned syncline on down-trajectory side. Crater is to 

left (Crater 44). 

Bomb-drop studies (Livingston and Smith, 1951, p. 

105-110) form the basis for groups 1, 2, and 3. Fins from 

1600AP and 2000SAP bombs are stripped from the body 

of the bomb and crumpled upon hitting sandstone (p = 

2.2 g/cm3) at velocities up to 0.23 km/s with no deformation of the bomb bodies. Rupture of bomb walls occurs upon impact with sandstone at velocities near 0.3 

km/s and contents such as ballast disperse and spill at 

velocities near 0.35 km/s. 2000GP bombs rebound from 

their craters in sandstone when impact velocities are 

near 0.29 km/s and penetrate less than their length at 

velocities less than 0.23 and 0.3 km/s. They are considered to be at the surface and unburied. 

Data for groups 4, 5, and 6 come from missile impacts. 

Projectile debris from craters in sandstone and limestone in these groups are scattered across the surface to 

60 m from the crater and none of it remains in the crater. 

At velocities exceeding 3.8 km/s, nearly all of the projectile, including coatings sheared and compressed 

fragments, are ejected when the target density is greater than 1.5 g/cm3. Pieces of deformed projectile are 

rarely found, and where found, are a few milimetres 

across. Lines between deformation groups were drawn 
B24 CONTRIBUTIONS TO ASTROGEOLOGY 

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Basa lt 

Granite 

Sandstone 

Lunar regol ith 

Common soils 

Loess 

Diatornaceous 

earth 

Pum ice 

0.1 0.5 

VELOCITY (KM/SECl 

1.0 5.0 

FIGURE 39.- Approximate velocities and densities for the six 

categories of projectile deformation and degree ofburial of projectile 

or pieces of projectile resulting from impact with natural materials. 

Solid lines separate categories of projectile deformation: (1) bending 

missile body and stripping of appendages, (2) rupture of missile and 

extensive internal damage, (3) rupture of components and spillage, 

(4) fragmentation of missile and components with separate scattered contorted pieces, (5) powdering, fragmentation into pieces 15 

em across and less and partial melting, and (6) powdering, fragmentation into pieces a few millimetres across and less, partial 

melting, and ejection of all or most of missile parts. Dashed lines 

separate categories of degree of burial. 

assuming deformation is proportional to target density 

times the square of the impact velocity. 

Burial of projectile is based mainly on small-scale 

impact data. Missile impact data for complete burial is 

represented by only one crater. The laboratory data are 

from the impact of a BB with diatomaceous earth at 0.15 

km/s (fig. 40). The BB penetrated about 2 diameters, 

forming a small tube. As shown in figure 40, the impact 

of a copper-jacketed lead .22 caliber bullet with 

diatomaceous earth (p = 1.0 g/cm) at 1.4 km/s did not 

produce a crater; rather, a camouflet formed beneath 

the surface of the target block connected to the surface 

by a small hole having about the same diameter as the 

projectile. Although banding in the diatomaceous earth 

can be traced across the camouflet, the brecciated cavity 

was found to have pieces of projectile scattered through 

it. Similar phenomena occurred for a missile impact 

crater in a target with a density near 1.2 g/cm3. No 

pieces of projectile were found in the crater walls or 

ejecta, nor were fragments of sheared and compressed 

target materials coated with powdered projectile. A 

crater produced by a 0.178-g chrome steel sphere impacting diatomaceous earth (p =0. 7 g/cm3) at 4.42 km/s 

produced a crater and much of the projectile remained 

as small pieces beneath the surface (fig. 40) in small 

tubes below the crater floor. 

The estimate of deformation, plotted (fig. 39) as a 

function of velocity of missile and density of material, 

represents a generalized description of impact 

phenomena and should not be taken as rigorous because 

of the large number of variables involved. Some 

suitably designed projectiles with large mass cross 

0 1 2cm 

L__j__j c 

FIGURE 40.- Sawed sections showing results of small-scale experimental impacts with diatomaceous earth illustrating variety of 

impact phenomena. A, BB impact at about 0.15 km/s produces 

tubelike crater several BB diameters deep and one wide. B, Impact 

of copper-jacketed .22-caliber bullet at about 1.4 km/s produces 

cavity filled with breccia of diatomaceous earth and projectile pieces 

(experiment by Glen A. Miller, U.S. Geological Survey). Cavity 

connected to surface by small hole one projectile diameter across. 

Result similar to camoufiet produced by deeply buried chemical 

explosives. C, Crater produced by impact of chrome steel sphere at 

4.42 km/s in diatomaceous earth at Ames Research Center Free 

Flight Range, NASA. 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B25 

sections penetrate rock and other natural materials to 

depths greater than 3.8 m at velocities near 0.3 km/s 

without being fragmented (Colp, 1968, p. 9, 12; Young, 

1967a). Pore-pressure effects may substantially alter 

the estimate of projectile burial. In water-saturated 

targets, penetrations of slender projectiles at low 

velocities are greater than those in dry to moist targets 

(Young, 1967a; see tables 3 and 1). At higher velocities, 

where projectile fragmentation does occur, craters in 

water-saturated targets are larger and ejection of 

target-projectile material more complete than in porous, dry to moist targets (Moore and Lugn, 1965). 

Response of target materials varies with projectile 

velocity and target density. Missile impacts produce 

crushing and disaggregation when the target material 

is rock. Target material compressed to densities near 

2.0 g/cm3 is abundant in craters in soils and materials 

with densities near 1.6 g/cm3 in groups 5 and 6. For very 

low velocity impacts in soils, some compression occurs 

(Colp, 1968) in a plug driven ahead of the projectile and 

rock is crushed (Colp, 1968; Hartman, 1959). Sheared 

and compressed target material is absent in watersaturated targets. 

QUANTITATIVE RELATIONS 

MISSILE-IMPACT CRATER SIZE AND ENERGY 

Quantitative correlations of dimensions of missile 

impact craters with each other and relative to missile 

kinetic energies show that: rim heights vary with rim 

radii, apparent crater radii with apparent crater depth, 

and rim radii with the sum of apparent crater depths 

and rim heights; apparent radii, apparent depths, crater 

volumes, and displaced masses vary with kinetic energy 

of the missile. Results of linear regression fits to the 

data in logarithmic form are shown in table 2 and 

figures 41 through 50. Not all craters were included in 

these least squares fits. Craters in water-saturated 

gypsum lake beds were excluded from the fit to data on 

volume, displaced mass, and kinetic energy because of 

the role of positive pore pressures in cratering. Others 

were excluded because they were not completely 

mapped, and for various other reasons. Craters 

excluded are listed in footnotes to table 2. 

For some of the plots, the kinetic energy of the missile 

is corrected for the angle of impact using the sine of the 

angle. This correction was based on data for hypervelocity impacts of steel pellets with lead targets 

(Bryan, 1962). 

Although the data show that the sizes of the craters 

correlate with the kinetic energy of the missiles, equations comparing apparent crater volumes and displaced 

masses with the kinetic energies of the missiles, corrected or uncorrected for impact angles, indicate that 

cratering becomes more efficient with increased kinetic 

energy; that is, the crater volume or displaced mass per 

unit of kinetic energy increases with kinetic energy. 

This increase is not accompanied by a significant 

change in crater shape as shown by the equation relating apparent depth and apparent radius. Rather, both 

the apparent depths and radii increase with kinetic 

energy in a manner consistent with greater cratering 

efficiency at greater kinetic energies. 

The anomalously large displaced masses of craters in 

water-saturated lake beds and moist gypsum lake beds, 

relative to their respective kinetic energies corrected for 

angle of impact (fig. 50), are noteworthy. Plotted points 

for the craters in moist gypsum lake beds (fig. 50) are 

subparallel to the linear regression line but everywhere 

lie above it, thereby showing greater cratering efficiency at greater kinetic energies for a given target 

material. This is discussed further below. 

COMPARISON WITH OTHER DATA ON 

EXPERIMENTAL IMPACTS 

There appear to be correlations and similarities 

between missile impact craters and laboratory experiments as well as some low-velocity impact experiments in the field. Comparisons are somewhat 

impaired for several reasons: there are no laboratory 

experiments in the materials of the missile impacts; 

kinetic energies in laboratory experiments rarely exceed 1011 ergs; many laboratory experiments are 

performed at reduced pressures, whereas missiles 

impact in an atmosphere of air; and most of the missile 

velocities cannot be specified. 

Increase of the efficiency of cratering with increase in 

the kinetic energy of the missile as found for missile 

impacts has been reported for craters produced by drill 

TABLE 2.-Results of least squares fits to missile impact data 

[Dimensions for equations are em, cm3 , g, ergs, and degrees] 

Parameters 

1 Average rim height. 

rim radius' 

2 Apparent depth. 

apparent radius2 

3 Apparent depth + avg. 

rim height, radius rim' 

4 Apparent radius, 

kinetic energy3 

5 Apparent radius, sine 

impact angle x kinetic 

energy3 

6 Apparent depth, kinetic energy4 

7 Apparent depth, sine 

impact angle > 

kinetic energy4 

8 Apparent volume, 

kinetic energy3 

9 Apparent volume, sine 

impact angle x 

kinetic energy" 

10 Displaced mass. 

kinetic energy3 

11 Displaced mass, sine 

impact angle x 

kinetic energy3 

12 Rim radius, 

kinetic energy4 

13 Rim radius, sine impact angle '. 

kinetic energy4 

Equation 

h =0.118 rr0.944 

d'a =0.558 raP.994 

da+h=0.571 rr0.997 

ra =10-3.934Ep 0.412 

ra =lo-4.369rsin 11Ep10.445 

d a = 10 -4.182Ep0.411 

da=lo,-4.588(sin 11Ep10.442 

V a =lo-11.433Ep1.205 

Va =lo-l2.660rsin 11Ep11.298 

Md = 1o-11.086EP1.195 

Md = 10-12.272rsin 11Ep11.284 

rr=10-3.311Ep0.376 

rr=1o-4.023(sin 11Ep 10.426 

Standard error 

of estimate 

0.078-0.178 

0.485--0.642 

0.506-0.644 

10-3.866_10 -4.002 

10-4.301_10-4.437 

10-4.082_10-4.282 

10 -4.488_10- 4.688 

10 -11.208_10 -11.658 

10 -12.433_10-12.887 

I0-10.845_10-11.327 

10 -12.027_10-12.517 

10-3.241_10-3.381 

10 -3.952_10-4.094 

'Sample size 51 !craters 1, 5, 9, 22, 23, 26, 35, 59. and 60 excluded!. 2Sample size 52 (craters 9, 22. 23, 26, 35, 57, 59 and 60 excluded). 3Sample size 50 (craters 7, 44, 9, 22, 23, 26, 35. 57, 59, and 60 excluded!. 4Sample size 53 !craters 7, 44, 9, 22, 23, 26, and 35 excluded!. 
B26 CONTRIBUTIONS TO ASTROGEOLOGY 

(/) 

w 

a: 

1-

w 

::2: 

i= 10 z 

w 

u 

~ 

I.C' 

100 rr, IN CENTIMETRES 

EXPLANATION OF TARGET 

MATERIALS 

o Water-saturated gypsum lake beds 

• Moist gypsum lake beds 

o Colluvium 

• Alluvium and soils 

t,. Sand 

A Fixed gypsum dunes 

x Rock 

1000 

FIGURE 41.-Comparison between average rim height (h) and rim 

radius (rr). Dashed line represents least squares fit to 51 impact 

craters. Because of superposition, only 48 points are shown. 

bits impacting synthetic stone and rock (Hartman, 

1959, 1962), bullets impacting cement and marble at 

speeds up to about 610 m/s (Vanzant, 1963), artillery 

projectiles impacting rocks at up to 878 m/s (Tolch and 

Bushkovitch, 194 7), and hypervelocity impact craters 

in basalt (Moore and others, 1965). Not all craters 

produced by projectile impact show an increase of 

efficiency with increased kinetic energy. The most 

notable exception is for impact cratering in cohesionless 

materials such as sand, where, for a given projectile, 

displaced mass is more nearly proportional to velocity 

than to kinetic energy and efficiency of cratering is 

therefore an inverse function of projectile velocity (Culp 

and Hooper, 1961; Cook and Mortensen, 1967; Oberbeck, 1970). For projectiles with constant velocity, 

displaced masses of craters in sand are proportional to 

the kinetic energy of the projectile raised to a power 

between 0. 795 and 0.877 (Oberbeck, 1970). For experiments conducted in air, Cook and Mortensen (1967) 

find that volumes of craters produced by projectiles of 

equal sizes and velocities are larger in coarse sand than 

in fine sand. 

Data on both ejected and displaced mass and kinetic 

energy for hypervelocity impacts with dense basalt 

(Moore and others, 1965) and sand (Oberbeck, 1970) 

extrapolated more than three orders of magnitude in 

energy converge near values of kinetic energies of 1015 

ergs and ejected or displaced masses of 17 x 106 grams. 

These data, chiefly for normal incidence impacts at 

reduced pressures, are superposed on missile impact 

data for kinetic energies corrected for angle of impact) 

between 1015 and 1016 ergs. This relation is shown in 

the plots of figure 51, which represent the equation of 

Moore, Gault, and Heitowit (1965) (density ratio taken 

as 1), Oberbeck's equations for projectile velocities of0.5 

and 5.0 km/s, and the equation for missile impact 

en 

w 

~ 100 w 

:2:: 

i= 

z 

w 

u 

z 

100 1000 

ra, IN CENTIMETRES 

FIGURE 42.-Comparison between apparent crater depth Cda) and 

apparent crater radius (r a). Dashed line represents least squares fit 

to 52 impact craters. Because of superposition, only 48 points are 

shown. 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B27 

cratering corrected for the angle of impact. For the 

experimental hypervelocity impacts with dense basalt, 

projectiles were accelerated to velocities of 0.88 to 7.3 

km/s, attaining energies of 4.9x 108 to 7.4x lOll ergs. 

Ejected masses2 (Me) ranged from several tenths of a 

gram to slightly more than 103 grams. For the experimental impacts with 200-700 11-m quartz sand, 

projectiles were accelerated to 0.5 to 5.0 km/s, attaining 

energies of 2 x 107 to lOll ergs. Craters had displaced 

masses between about 10 and 6x 103 grams. 

A crater produced by a missile impacting a sand dune 

of 40- to 100-mesh (0.147-0.417 mm) gypsum sand at 

known velocity allows a comparison with equations 

derived from small projectile impacts with sand in the 

laboratory. The missile produced a crater with an 

apparent volume of 97.5 x 106 cm3 in the gypsum sand 

upon impact at 3.89 km/s with a kinetic energy of 

73.5 x 1014 ergs. According to the Command at White 

Sands, the mass per unit area of the missile was between 95.5 and 24.8 g/cm2, depending on how it hit. A 

_•Ejected mass 1M e J for small craters in basalt is the mass of material ejected from the crater. Displacement mass (Md) is the product of target density and apparent crater volume. 

500 l I l I I I I l I I I I 

/ r / - / 

/ 

/ l! t- / - / 

/ 0 

~/ 0 

/ ... t- .., J' • -

~& i", Ul ... tf• w ./ 

a: , 

AI ~ I- 100 t-

. "' w 6 - ~ t- / 

/ - f:: r • ? x• - z .. / ~ w r / -

u 0 / ,.... /o - ~ / 

/ 

J' 

._r. t- / - / 

+ / 

ttl - - "0 

- -

- -

10~~ -~11----------~----~--~'---~'~'--~'~''~ 60 100 1000 

r,, IN CENTIMETRES 

FIGURE 43.-Comparison between the sum of apparent crater depth 

and rim height (da and rh) with rim radius (rr)· Dashed line represents least squares fit to 51 impact craters. Because of superposition, only 42 points are shown. 

(J) 

w 

a: 

1-

w 

:2: 

i= 

z 

w 

() 

z 

FIGURE 44.-Comparison between apparent radius (r a) of crater and 

kinetic energy of missile (EP). Dashed line represents least squares 

fit to 50 impact craters. Because of superposition, only 46 points are 

shown. 

1000 

(J) 

w 

a: 

Iw 

~ 

f:: 

z 

w 

u 

~ 

.... "' 100 

40~----~--~~~~~~----~--~~~~~~ 

1Q14 1015 1Q16 

SIN(} EP, IN ERGS 

FIGURE 45.-Comparison between apparent radius (ra) of crater and 

product of sine of angle of impact and kinetic energy of missile (sin 8 

EP). Dashed line represents least squares fit to 50 impact craters . 

Because of superposition, only 41 points are shown. 

mass per unit area near 95.5 g/cm2 is most probable. 

Mortensen (1967), to explain his data on impact of .30-

caliber and .22-caliber bullets in sand at velocities up to 

1 km/s, proposed an equation of the form 

Ep 

m 

A 

where 

Ep is the kinetic energy of the projectile, 

m is the mass of the projectile, 

(14) 

A is the cross-sectional area of the projectile at 

impact, 

Va is the volume of the crater, 
B28 CONTRIBUTIONS TO ASTROGEOLOGY 

en 

w 

0: 

fw 

::2: 

i= 

z 

w 

(.) 

~ 

.... ::. 100 

40L-----~~--~~~~~----~--~~~~~~ 

1Q14 1Q15 1Q16 

EP,IN ERGS 

FIGURE 46.-Comparison between rim radius (rr) and kinetic energy 

of missiles (Ep). Dashed line represents least squares fit to 53 impact 

craters. Because of superposition, only 43 points are shown. 

V p is the velocity of the projectile, and 

K is a coefficient. 

The value of the coefficient K depends on grain size of 

the target. For +20--14 mesh (0.833--1.17 mm) sand,K is 

86.4; for +4~28 mesh (0.295-0.589 mm) sand,K is 110; 

and for+ 100--60 mesh (0.147-0.246 mm) sand,K is 210. 

Substitution of the appropriate values for the missile 

impact crater yields values of K between 27 and 103, a 

result indicating the missile impact crater is larger 

than expected. Adjustments for angle of impact further 

reduce these values of K. 

It can be shown that Oberbeck's results (1970) can be 

fitted to equations of the form 

E 

---=-P-=CV (15) 

( ~ ) V2 M d P' 

400 

en 

w 

a: 

fw 

~ 

i= 100 

z 

w 

u 

~ 

ia "'0 

20~----~~--~~~~~----~--~~~~~~ 

1 Q14 1 Q1 5 1 Q16 

EP, IN ERGS 

FIGURE 47.-Comparison between apparent depth (d3 ) and kinetic 

energy of the missile (EP). Dashed line represents least squares fit to 

data of 53 impact craters. Because of superposition, only 46 points 

are shown. 

w 

a: 

fw 

~ 

i= 

z 

w 

u 

~ 

!D 

::> 

u 

ID 

0 

... 

~ 

ia 

> 

10 

1.0 

0.5 

1Q14 1Q15 

EP' IN ERGS 

FIGURE 48.-Comparison between apparent crater volume (V3 ) and 

kinetic energy (EP). Dashed line represents least squares fit to data 

for 50 impact craters. 

where C =4 7± 7. For the missile impact crater in gypsum 

sand (Crater 56), C is 14:3 to 27.9 or 9.9 to 19.4 when 

corrected for the angle of impact using (sin 8)%. The 

results are of same order of magnitude, but Crater 56 is 

larger than predicted. Direct comparison of the 

displaced mass and the kinetic energy x sin 8 for Crater 

56 with Oberbeck's equation predicting the larger 

displaced masses indicates that Crater 56 is 1.8 times 

larger than expected. Indeed, it is about 1.8 times larger 

than the line of the least squares fit to the missile impact 

data. By all standards, Crater 56 is larger than 

expected. The reason for this is not entirely clear. The 

difference could arise from differences in projectile 

properties, errors in energy estimates for the missile, 

the effects of air pore pressures, or local terrain slope. 

Low-velocity impact studies have been conducted in 

the moist gypsum lake beds at White Sands Missile 

Range (Young, 1967b). Slender projectiles, weighing 

1.02xl05 to 1.14xl05 grams and 13.7 to 20.3 em in 

diameter, were dropped at velocities between 48 and 84 

m/s, producing tubelike craters 51 to 134 em deep filled 

by the projectile. Displaced masses, taken as the target 

density x projectile cross section area x depth of 

penetration, yield ratios of kinetic energy to displaced 

masses between 0.46x 108 and 0.99x 108 ergs/g. These 

ratios are comparable to those of missile impact craters 

in the same material, which range between 0.32xl08 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B29 

ergs/g for the larger ones and 1.2 x 108 ergs/g for the 

smaller ones. The values are surprisingly close to those 

of the low-velocity penetrators, although there is little 

correspondence in characteristics of the missile impact 

craters and the low-velocity penetration. 

COMPARISON WITH CRATERS PRODUCED BY EXPLOSIVES 

Sizes of craters produced by missile impacts are 

generally near those produced by chemical explosives 

when the kinetic energies of the missiles (corrected for 

the angle of impact) are equal to the TNT equivalent 

energy of explosives with shallow depths of burial 

(Moore, Kachadoorian, and Wilshire, 1964; Moore, 

1966a). Empirical correlations have been suggested for 

small laboratory impact craters in rocks and small 

explosion craters (Gault and others, 1963, p. 29; Gault 

and Moore, 1965) and shown for small experimental 

impact craters and explosive craters in sand (Oberbeck, 

1970, 1971). The problem of exact comparisons for a 

variety of natural materials and projectile conditions is 

not resolved, however, The effects on impact cratering 

of target properties such as porosity, cohesion, angle 

of internal friction, moisture content, and equation of 

state and projectile properties such as density, velocity, 

size, shape, and equation of state have not been studied 

in sufficient detail. 

200 

100 / 

/ 

/ 

/ 

/ 

/ 

0 / 

• / 

/ 

I 

/ C/J • • I 

:2: , <x: / 

0: I 

(!) .. • '} 0 

(0 

s 6 ¥. ~ ·t .. •• 2,/. -o '/ 

:2: 10 }'• 

/. 

// ... / 

X I • / • . / / • / 

/ 

I 

0 6./1 

I •• 6 / 

• / • 0 / 

/ 

/ 

/0 

1 

1Q14 1Q15 1Q16 

EP, IN ERGS 

FIGURE 49.-Comparison of displaced mass (Md) and kinetic energy of 

missile (EP). Dashed line represents least squares fit to data for 50 

impact craters. 

200 

/ 

6 I , 

/ 

100 , 

/ 

/ 

/ 

/ 

0 I 

a / 

I .. / , • • I 

(/) / 

2 , 0 

<x: . •/ a: ... / ' 0 (.9 

~ -t. \Q .... ~ R~/· 

z 

- 10 ~~ 

u /. 

2 1/ ... 

/ 

X / 

• I •• e I / 

I 

I 

/ 

I 

0 6111 I 

I .·6 • • / , 0 , 

I 

/o 

1 

1014 1 o15 1016 

SIN() EP' IN ERGS 

FIGURE 50.-Comparison of displaced mass (M d) and product of sine of 

angle of impact and kinetic energy of missile (sin(} Ep)· Dashed line 

represents least squares fit to data for 50 impact craters. 

Craters produced by explosives are markedly dependent on the scaled depth ofburst3 (Duvall and Atchison, 

1957; Nordyke, 1961; Vortman, 1963); the equivalent 

scaled depth of burst for an impact event is not clear. 

Both the tube-crater in diatomaceous earth produced by 

the BB (fig. 40A) and the craters produced by 

low-velocity penetrators (Young, 1967b) bear little 

resemblance to craters produced by chemical explosives. The breccia-filled cavity produced in diatomaceous earth by the .22-caliber bullet (fig. 40B) is similar 

to camoufiets produced by charges of chemical explosives with large scaled depths of burst that do not 

produce craters (U.S. Army Corps of Engineers, 1958). 

Some missile impact craters may be similar in that a 

breccia-filled cavity underlies an anomalously small 

crater (such as Crater 43). At velocities of 4.43 km/s, 

small craters are produced in diatomaceous earth (fig. 

3The scaled depth of burst is a ratio of dimensions describing experimental conditions for an 

explosive event and is used to compare results from events with differing conditions. For 

cube-root or Lampson scaling, the scaled depth ofburst is equal to the actual depth ofburial of 

the explosive <dob I divided by the cube root of the TNT weight-equivalent of the explosive (WI 

or d0 b!W'13. It is commonly expressed in ft/(lbl 1/.1 (Duvall and Atchison, 19571. For Nevada 

Test Site data, the scaled depth of burst has been taken as the actual depth of burial of the 

explosive divided by the 3.4th root of the TNT weight-equivalent of the explosive of 

dobiW'/3.4. It is commonly expressed in m/(kilotonl 113.4 (Nordyke, 19621. Other scaling laws 

use different scaled depths of burst such as overburden scaling (Chabai, 1965), fourth-root 

scaling (Chabai, 1965; Herr, 1971 I, and counterpressure scaling (Sun, 19701. Small 

experimental impact craters in rock imply scaling laws for which scaled depths of burst would 

differ from all of those given here (Moore and others, 1965; Mandeville and Vedder, 1971; 

Gault and Moore, 19651. 
B30 CONTRIBUTIONS TO ASTROGEOLOGY 

(/) 

::2: 

<t: 

a: 

(.!) 

tO 

S? 

~ 

-o 

::2: 

a: 

0 

::2:., 

100 

10 

1 

1014 

EXPLANATION 

------ Missile impact craters 

- ·- Craters in sand (Oberbeck, 1970) 

---- Craters in rock (Moore and others, 1965) 

--- Missile impact craters, 

standard error of 

estimate 

1015 

EP' IN ERGS 

1016 

FIGURE 51.-Ejected (Mel or displaced (Mdl mass and kinetic energy 

(Epl corrected for angle of impact (sin 8) for missile impact craters, 

extrapolation ofhypervelocity impact equation for rock targets, and 

extrapolation of impact data on craters in sand. Results compare 

well in the region of 1015 to 1016 ergs. 

40C). The effective scaled depth of burst for impacts 

with porous targets varies, especially with velocity. 

For dense coherent rocks such as basalt, the dependence between cratering and projectile velocity is 

different. Projectiles at velocities near 0.21 km/s simply 

bounce upon impact and no crater is produced. 

Low-velocity projectiles with large masses per unit area 

(Young, 1967b), form tubelike craters. Small projectiles 

at velocities from 0.88 to 7.3 km/s produce craters by a 

combination of crushing and spallation (Moore, Lugn, 

and Gault, 1962). Va~iations similar to those described 

occur with missile impacts as in the very small craters 

in rock, for example, craters 22 and 23 in sandstone and 

limestone (fig. 37). 

As part of a passive seismic study of missile impacts 

(Latham and others, 1970), craters were produced in 

colluvium and alluvium near the missile impact craters 

using commercial explosives detonated at small scaled 

depths of burial. Comparison of the displaced masses of 

craters produced by missile impacts and explosives with 

energies near the kinetic energies of the missiles 

(corrected for the angle of impact) show they are 

reasonably close (fig. 52; table 4). For impact craters in 

colluvium, there was no evidence for a camouflet; the 

craters compare well with explosive craters with small 

scaled depths of burst (0.15 m/(kg)lf3 or 0.38 ft/(lb/13 ). 

Other impact craters in colluvium are close to the 

explosive craters in colluvium plotted in figure 52. As 

other data on craters produced by chemical explosives 

(Robertson, 1966) agree fairly well with the results for 

colluvium (fig. 52), the results appear valid. Both the 

impact crater (Crater 43) and explosive craters in 

all u vi urn are anomalously small for their energies 

when compared with the other craters in alluvium. One 

impact crater(Crater15) in alluvium about a mile to the 

south of Crater 43 is consistent with the results for 

"impacts and explosive craters in colluvium. The cause 

for the samll explosive craters may be a caliche layer in 

the alluvium. Mapping shows one of the explosive 

craters (0.12 m/kg% or 0.29 ft/lb%) was clearly affected 

by this layer because a flat floor with a central peak was 

produced at the appropriate depth for the caliche layer 

(see also, U.S. Army Corps of Engineers, 1958b). On the 

(/) 

::2: 

<t: 

a: 

(.!) 

~ 

.:0 

::2: 

107 

106 

105 

EXPLANATION 

e, .6. Explosive craters 

0, 61 mpact craters 

e, 0 Craters in colluvium 

.6., 6 Craters in alluvium 

cf, l5 Impact craters at same 

site as explosive crater Number indicates 

scaled depth of 

burial of explosive 

0 • 

0.32 

0 

0.29, . 

~·· 

0.36 •• •• 

~ ....... ..·... !Y 

• 0.18 

1013 1014 1015 

EXPLOSIVE ENERGY OR SIN 8 EP, IN ERGS 

FIGURE 52.-Comparison of displaced masses of craters produced by 

chemical explosives (after Robertson, 1966), chemical explosive 

experiments at White Sands Missile Range, and missile impact 

craters with comparable energies. Filled circles represent craters 

produced by chemical explosives in colluvium with scaled depth of 

burst indicated; open circles, missile impact craters in colluvium; 

flagged open circle, missile impact crater in same material as 

chemical explosive craters; filled triangles, craters produced by 

chemical explosives in alluvium with scaled depths of burst 

indicated; open triangle, missile impact crater in alluvium near 

explosive craters; flagged open triangle, missile impact crater in 

same material as explosive crater. Scaled depth of burial is in 

ft/(lb)l:, n.o ft/(lb)'" =0.40 m/kg'/" ). 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B31 

other hand, ejecta from the missile impact crater 

contained large amounts of the caliche and there was no 

flat floor. Because there were few or no missile pieces in 

the ejecta, the pieces must have remained below the 

surface in a brecciated mass. This suggests that Crater 

43 may have had a camouflet somewhat like that in 

diatomaceous earth (fig. 40B). Simple generalizations 

about equivalent scaled depths of burial for impact 

craters are unjustified and few simple correlations can 

be expected for projectile velocities as great as 7 km/s 

(see for example, Gault and others, 1966; Moore and 

Robertson, 1966; Moore, Gault, Heitowit, and Lugn, 

1964; Moore and others, 1965). 

Additional parallels between explosive craters and 

missile impact craters exist. Both explosive and impact 

craters produced in very wet fine-grained materials are 

larger than their dry counterparts for energies near 

1015 ergs (Moore and Lugn, 1965; fig. 53). The missile 

impact craters in water-saturated targets (Craters 7 and 

44) are five to six times larger than the least squares 

regression line (fig. 50). Generalized results from 

explosive cratering experiments (Robertson, 1966) yield 

a similar result, and explosive craters with energies 

near 1015 ergs are about 10 times larger than their dry 

counterparts (fig. 53). Further, both explosive and 

impact craters produced in a wide variety of natural 

materials exhibit a large amount of scatter (fig. 52). 

Craters produced in sand, rock, and alluvium with the 

same scaled depths of burial and charge energies differ 

in size and much of the scatter in the missile impact data 

may result from such effects. 

Structurally, explosive craters and missile impact 

craters are similar. Mixed breccias were produced by 

the Jangle U and Teapot ESS explosive cratering 

experiments (Shoemaker, 1960) and conjugate fractures are produced in materials around detonated 

explosives (AUsman, 1960). Sheared and compressed 

alluvium are common in ejecta from craters produced by 

explosives at the Nevada Test Site. 

DISCUSSION OF DATA 

Six aspects of the data on missile impact craters are 

critical: (1) the relation of the symmetry of the crater to 

the path of the missile, (2) the effect of the angle of 

impact on crater size, (3) the relation of crater size to 

impact energy, (4) the compression of target material, 

(5) the effects of water in the target material, and 

(6) extrapolation of data on sizes of missile impact 

craters to larger and smaller craters. 

SYMMETRY AND PATH OF MISSILE 

As mapping has shown, ejecta and crater profiles are 

normally bilaterally symmetrical about the plane of the 

missile trajectory, a result of the oblique trajectory. 

--Wet materials / 

--Dry materials / 

108 o Impact craters / 

in water- / 

saturated / 

lakebeds / 

/ 

/ 

106~--~--~~~~~~----~~--~~~~ 

1014 1015 1016 

SIN() EP OR EXPLOSIVE ENERGY, IN ERGS 

FIGURE 53_-Comparison of impact and explosive (after Robertson, 

1966) craters in dry to moist targets and water-saturated targets. 

Note that craters produced in wet materials are larger than those 

produced in dry materials when the energies are the same and 

scaled depths are equal. 

Conservation of momentum suggests that this type of 

symmetry should arise from an oblique impact and that 

there should be a concentration of ejecta downtrajectory. A rough estimate of the direction of origin of 

the missile can be made when the crater is on flat 

terrain. This has been done for a number of craters 

using chiefly thick ejecta patterns around the crater and 

observing the side of the crater which has little or no 

thick ejecta. The mapped lines of thick ejecta extending 

in lateral directions from the up-trajectory side of the 

crater tend to be at right angles to the trace of the 

missile. 

Estimates of direction of origin for a number of craters 

are plotted in figure 54, where it may be seen that one 

group of missiles originates from a point along an 

azimuth of 35°, a second group from points along an 

azimuth between 135° and 195° (reference for azimuths 

is arbitrary). As these azimuths are consistent with the 

directions of the launch sites, crater symmetry yields 

some information on the direction of origin of the 

missile. 

ANGLE OF IMPACT 

The effect of angle of impact on crater size is not 

clearly understood. The sine ofthe angle of impact was 

used here to compensate for the effect of the oblique 

trajectory on crater size, in agreement with data on 

hypervelocity impacts with lead targets (Bryan, 1962). 
B32 CONTRIBUTIONS TO ASTROGEOLOGY 

Some workers have reported a sine-squared dependence 

with angle of impact (Partridge and Van Fleet, 1958). 

This does not seem reasonable for missile impact craters 

since it would increase the slope of the volume or 

displaced mass-energy curves significantly. Data of 

other workers (Gault and others, 1965, p. 129), using 

sand targets, indicate that the kinetic energy should be 

corrected using the two-thirds power of the sine of the 

impact angle. This correction would not critically affect 

the missile impact results reported here. For impact 

angles less than about 15°, a furrow or a chain of craters 

may be produced. Such a result has been obtained for 

laboratory impacts in sand with angles of impact of 4° 

(Swift and others, 1970). 

The possibility that a large angle of impact might 

actually result in smaller apparent craters in certain 

target materials, especially porous ones, and with 

certain projectiles, especially dense, long slender ones, 

cannot be ignored. In such cases shock and stress waves 

could propel projectile and target materials chiefly in 

the directions of the trajectory but partly radial to it. For 

a vertical impact, materials would then be driven 

mainly downward in the target, resulting in camoufiets 

such as the one described for diatomaceous earth. For an 

oblique impact, most of the shock and stress waves 

would propagate in the target material along the 

trajectory but some would propagate upward at an 

angle to the local surface. Radial components of the 

waves would interact with the local free surface 

ejecting material to produce a larger crater than that fo; 

a vertical impact. Morphology of the missile impact 

craters, the cross sections through them, and ejecta 

distributions support this. With very small angles of 

impact, furrows would be produced. The largest 

apparent craters in porous rocks, then, could result from 

some angle of impact between perhaps 30° and 60°. 

CRATER SIZE AND ENERGY 

Linear dimension~ of the craters were found to be 

proportional to the kinetic energies of the missile 

(corrected or uncorrected for the angle of impact) raised 

to a power near 0.4 and the relation of crater volume and 

displaced masses with energy was commensurate with 

those for the linear dimensions (table 2). This result 

differs significantly from Lampson scaling for explosive 

cratering (see for example, Duvall and Atchison, 1957), 

and Nevada Test Site scaling (Nordyke, 1962). Lampson 

scaling implies linear dimensions are proportional to 

the cube root of energy and that crater volume is 

proportional to energy; the Nevada Test Site scaling 

indicates linear dimensions are proportional to the 1/3.4th power of energy or charge weight. Indeed, the 

results for missile impacts are more akin to data on 

small laboratory impact experiments with rocks for 

40r-----------------------------------~ 

...J 

<( 

> za: 

-w 

cnt-

~~ <(:r 

utu. :> 20 0~ 

a:-

WN 

ID<( 

~0 

:>~ z :r 10 

u 

<( 

w 

90 180 270 

AZIMUTH (DEGREES) 

FIGURE 54.-Azimuths of traces of missile estimated from crater 

morphology and ejecta distribution. Reference for azimuths is 

arbitrary. 

which volumes and displaced masses are proportional to 

the 1.189th power of the projectile kinetic energy. Such 

a relation could arise for a number of reasons: (1) some of 

the data on missile impacts are near a threshold condition for crater formation; (2) the effective strength of 

the target material decreases with increase in size· and 

(3) masses, sizes, length-to-width ratios, and o~ien­ tations of the missiles at impact differ in a systematic 

but unknown manner with energy. It is not possible to 

differentiate the effect of these parameters; their possible effects are discussed below. 

Some of the craters produced may be near a velocity or 

specific kinetic energy threshold below which craters do 

not form. This threshold may be of two types. The first 

relates to dense cohesive materials such as rock for 

which no craters are produced when the specific kinetic 

energy is too small. For the impact of 14-inch-diameter 

hemispherical drill bits impacting synthetic stone at a 

velocity of 4.3 m/s, craters form by crushing and spalling 

above kinetic energies of 4.1 x 108 ergs; but below this 

energy no spalling occurs and relatively small craters 

are formed (Hartman, 1959). A BB impacting basalt at 

velocities near 0.15 km/s bounces without producing a 

crater. Some missile impacts with rock may be near 

such an energy threshold (Craters 22 and 23; fig. 37). The 

threshold of the second type is a factor in cratering in 

porous targets, illustrated with diatomaceous earth (fig. 

40). At low velocities small apparent craters result 

because subsurface breccia-filled cavities are produced 

whereas at higher velocities more nearly hemispherical 

shock and stress waves produce a crater by ejection and 

spallation of target material. The existence of a threshold condition could mean that equations of the form 

given in table 2 are not correct, that the fit is of the form 

(16) 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B33 

where K is a coefficient, n is a power coefficient, andE 0 is 

threshold energy required for cratering. Data available 

are not sufficient to test such an equation for the missile 

impact craters. 

Crater size-energy relations similar to those for the 

missile impact craters have been reported by a number 

of observers (Hartman, 1959; Vanzant, 1963; Moore and 

others, 1965; Mandeville and Vedder, 1971) for very 

small impact craters. The data have been explained as a 

result of an increase in the ratio of body forces and 

surface forces with increase in size of event (Vanzant, 

1963) and a decrease in strength of materials with 

increase in size because of defects which statistically 

increase in length or become prevalent in jointed or 

fractured materials (Moore, and others, 1965; Hubbert 

and Willis, 1957). 

The third possibility cannot be explored in any detail 

because data available are not complete. If missiles with 

lower kinetic energies impacted with an orientation 

systematically different than those with higher energies, the mass per unit area of the impacting missiles 

could conceivably produce a systematic bias in the relation of crater dimensions to kinetic energy. Alternatively, some other property such as bulk density of 

the missiles may vary systematically with kinetic 

energy. 

COMPRESSION OF TARGET MATERIAL 

Large parts of the ejecta and mixed breccia beneath 

the crater floors are composed of sheared and compressed target material when the target material is 

compressible and projectile conditions are suitable. 

Compressible target materials include alluvium, indurated gypsum dunes, and sand. For some craters as 

much as 20 to 30 percent of the ejecta is composed of 

fragments compressed to densities as high as 2.2 g/cm3 

from materials with initial densities of 1.2 to 1.6 g/cm3. 

The fragments are bounded on some or all sides with 

striated and grooved surfaces showing movement 

between fragments and indicating high confining 

pressures. 

Both high confining pressures and compression of 

target material is an expected result from impact craters in porous materials. Graphic impedance match 

solutions for peak shock pressures (Gault and Heitowit, 

1963) resulting from the impact of aluminum and nylon 

projectiles with porous targets at 3.9 km/s are one 

hundred to several hundred kilo bars, as shown in figure 

55A, a plot of data on shock compression of natural 

FIGURE 55.-A, Graphic impedance match solutions for peak shock 

pressures produced by the impact of nylon and aluminum projectiles 

with dry soils and sand, water-saturated sand, and granite at 3.9 

km/s. B, Compression of dry soils, sand, and water-saturated sand in 

shock wave. Note sizable compression of soil at shock pressures as 

low as 5 to 10 kbar. After Bass, Hawk, and Chabai, (1963l. 

materials after Bass, Hawk, and Chabai (1963). Shock 

pressures this high produce much compression of some 

materials. Ratios of compressed volume to original 

en 

a: 

<( 

Cll 

0 

_J 

~ 

z 

w 

a: 

::> 

en 

en 

w 

a: 

a. 

200 

100 

X 

X 

0 o 1 2 3 4 

PARTICLE VELOCITY,IN mm/,u-S 

en 

a: 

~ 200 

0 

_J 

~ 

~ 

w 

a: 

::> 

en 

~ 100 

a: 

a. 

X 

0.4 

COMPRESSED VOLUME/ 

ORIGINAL VOLUME 

EXPLANATION 

0 Dry alluvium 

x Playa 

• Dry sand 

(41 percent porosity) 

-. Dry sand 

(22 percent porosity) 

Water-saturated sand 6 (41 percent porosity) 

o Granite 
B34 CONTRIBUTIONS TO ASTROGEOLOGY 

volume are 0.57 to 0.38, corresponding to compressed 

densities of about 3.2 to 4.0 g/cm3 for original densities 

(p0 ) of 1.3 and 1.54 g/cm3 (fig. 55B ). Compression of sand 

(p0 =1.6 g/cm3) and alluvium (p0 =1.8 g/cm3) in shock 

waves to densities of2.0 g/cm3 may occur at pressures as 

low as 25 to 30 kbar. For low density alluvium (p0 =1.54 

g/cm3), a shock pressure as low as 10 kbar can result in 

compression to densities near 2.0 g/cm3. Compression of 

dry target material is expected for projectile velocities 

down to 1 km/s and probably less. 

WATER CONTENT 

Missile impact craters in water-saturated gypsum 

lake beds and in moist gypsum lake beds have two 

features in common. Their ejecta includes little or no 

sheared or compressed target material and the craters 

tend to be larger than those in the drier materials (fig. 

50). The craters in water-saturated gypsum lake beds 

(Craters 7 and 44) have displaced masses five to six times 

larger than the regression line in figure 50; those in 

moist gypsum lake beds are 1.5 to 2.5 times larger. 

Hugoniot data suggest that peak shock pressures will be 

greater (fig. 55) because initial densities (p0 =1.98) and 

water content are greater. Absence of evidence for 

compressed material must be related to water content 

and decompression. The large crater sizes may be the 

result of large transient positive pore pressures, which 

would reduce the shear stress required for rupture 

(Hubbert and Rubey, 1959). 

A simple analysis will illustrate how positive pore 

fluid pressures could affect crater size. The shear 

strength of a soil can be described (Hubbert and Rubey, 

1959)by 

T=±[ T0 +(s -p) tan¢], 

where 

T is the shear stress required for failure, 

T 0 is the cohesion, 

s is the normal stress, 

p is the pore fluid pressure, and 

<P is the angle of internal friction. 

(17) 

When positive pore fluid pressures equal the normal 

stress across the plane of failure, T=T0 and the angle of 

internal friction is effectively zero. The work expended 

in forming a hemispherical crater (w8 ) against the 

compressive strength, which is twice the shear strength 

for an angle of internal friction of zero, is 

Consider the case of the water-saturated target. If To is 

taken as 107 dynes/cm2, s =p for a water-saturated 

condition, and r 2, the final radius of the hemispherical 

cavity, is 280 em, then 

Consider the case of the dry target. When p is zero, the 

shear strength is a function of the normal stress and the 

compressive strength is a function of shear strength and 

angle of internal friction. Peak shock pressure decay for 

the Stagecoach cratering experiments in Nevada Test 

Site alluvium (Sun, 1970, p. 2014) may be expressed by 

P =4.637 x 1015r - 2.423, (19) 

whereP is the peak shock pressure and r is the distance 

from the origin of shock. For the Stagecoach crater with 

a radius near 1, 7 86 em and a depth of burst of 1, 042 em 

(Sun, 1970, table 2), the peak shock pressures decayed to 

4. 7 x 107 dynes/cm2 at the crater edge. If peak shock 

pressures decay to this value at the edge of a hemispherical missile impact crater in alluvium with a radius 

of 155 em, the equation for pressure for the missile 

impact is 

(20) 

Where P is considered to represent the maximum 

principal stress in a Mohr-Coulomb diagram (Hubbert 

and Rubey, 1959). It can be shown that the normal 

stress Sis approximately 4/9 of the maximum principal 

stress so that 

s=3.9x 1012r-2.423. (21) 

When this equation for s is inserted in equation (18), 

107r 3 2.7x 1012r0.577 155 

= 18 [ -3-+ 0.577 ] 0 

= 1.8 x 1015 ergs. 

These calculations indicate that twice as much energy is 

expended in forming a hemispherical crater in dry 

all u vi urn with a cohesion of 107 dynes/ em 2 as in forming 

a hemispherical crater in water-saturated material, 

sixtimes larger, and with the same cohesion. The larger 

value for the crater in alluvium might be too large 

because positive pore pressures due to air have been 

neglected. In any event, the difference can be accounted 

for semiquantitatively using the Mohr-Coulomb failure 

criteria and effects of pore pressures. 

EXTRAPOLATION TO LARGER SIZES 

Extrapolation of the equations representing the relations between dimensions of the missile impact craters and kinetic energies (see table 2, fig. 56) to impact 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B35 

16 

15 

14 

13 

(/) 

2 12 <( 

a:: 

(.9 11 

~ 

(/)- 10 

(/) 

<( 

2 9 

0 

w 8 u 

<( 

_j 

"-(f) 

0 6 0 

r5 

0 

_J 

Sand 

~Sedan 

EXPLANATION 

0 

------------

Wet material 

____ .!., ___ _ 

Hard rock 

X 

Dry alluvium 

Numbers indicate scaled 

depth of burial 

11 12 13 14 15 16 1 7 18 19 20 21 22 23 24 

LOG10 ENERGY, IN ERGS 

FIGURE 56.- Comparison of data on craters produced by chemical and 

nuclear explosives (after Robertson , 1966) and experimental impact 

craters. Data on impact craters in sand from Oberbeck (1970). Data 

on impact craters in rock from Moore , Gault, and Heitowit (1965). 

energies greater than 1016 ergs is probably not valid. 

Large volumes of rock are commonly, if not always, 

fractured and jointed (see for example, Hubbert and 

Willis, 1957, p. 159-160) such that on a grand scale the 

rocks are made up of cohesionless angular blocks. 

Displaced masses and energies of explosive craters, 

which compare well with missile impact energies in the 

region of 1015 ergs (fig. 56), yield no indication that such 

an extrapolation would be valid. Large explosive craters 

in very cohesive, but jointed and fractured basalt 

suggest scaling laws change above 1015 ergs (Nordyke 

and Wray, 1964). 

The data on these missile impact craters may lie in a 

transitional region where scaling laws change. The 

relations between displaced masses and energies for 

impact craters in sand (Oberbeck, 1970) and rock 

(Moore, and others, 1964) intersects near 1015 ergs of 

kinetic energy. Extrapolation of equations for craters in 

sand (Oberbeck, 1970) to kinetic energies of 1020 ergs 

yield displaced masses of 1011.52 and 1011.34 grams, 

which lie within the bounds drawn for alluvium (fig. 56). 

Extrapolation using equations for small impact craters 

in rock and missile impacts fails to predict displaced 

masses oflarge explosive craters in alluvium with small 

scaled depths of burial. Apparently cohesion and 

strength of rocks become less important for large 

cratering events (Gault and Moore, 1965), because the 

pervasive fractures and joints in rocks make them 

behave more like cohesionless materials. Despite 

unknowns and discrepancies between individual sets of 

data, cratering experiments using chemical and nuclear 

explosives provide the data for best estimates of energies of large natural hypervelocity objects producing 

large impact craters on the Earth and Moon 

(Shoemaker, 1960, p. 431; Baldwin, 1963, ch. 7). 

APPLICATIONS TO LUNAR PROBLEMS 

Data collected during the study of missile impact 

craters apply to a number of problems of lunar studies: 

(1) the nature of the lunar surface materials (Moore, 

1966b, 1968b), (2) sizes and morphologies of craters 

produced by the impact of Ranger spacecraft (Moore, 

1968a) and other vehicles (Latham and others, 1970), 

(3) the explanation of certain features imaged by 

Surveyor (Shoemaker, Morris, and others, 1969), 

(4) support for the Apollo passive seismic experiment 

(Latham and others, 1970), (5) interpretation of craters 

seen in Apollo orbital photographs (Moore, 1971b, 

1972), (6) training of astronauts, and (7) properties of 

returned lunar samples. 

NATURE OF LUNAR SURFACE 

The use of crater morphology to assess the nature of 

lunar surface materials using missile impact data and 

other data on explosive craters requires that: (1) the 

craters employed be produced by impact, (2) the 

existence and nature of crater erosion be recognized, 

(3) the relation between crater morphology and crater 

size be understood, and (4) the resolution and angle of 

illumination of the photographs be taken into account. 

The first requirement was justified for small craters, as 

meteors and meteoroids are known to bombard the 

Moon. The second requirement was fulfilled when erosion of lunar craters by micrometeors and meteors was 

postulated (Moore, 1964), then substantiated by Ranger 

images (Trask, 1966) and subsequent photography 

(Soderblom, 1970). Such an interpretation of the erosional process requires that only fresh, or eumorphic, 

craters with maximum relief be used to appraise the 

mechanical properties, because floors, blocks, and rims 

of the older craters are partly filled, degraded, and 

subdued. The third requirement has been established 

by experimentation and observation. Craters in rock 

several metres in diameter tend to be rimless, whereas 

those in cohesionless sand have raised rims. Craters 

near 30 m across have rims regardless of the material 

(see for example, Spruill and Paul, 1965). Ejecta of 30-m 

craters in rock contain a great number of blocks up to 

about 1 m across; craters in sand contain no blocks. 

Large craters in rock have both raised rims and large 

blocks in the ejecta (Spruill and Paul, 1965; Boutwell, 
B36 CONTRIBUTIONS TO ASTROGEOLOGY 

1928). The last requirement, resolution, is illustrated in 

figure 57 by a 33-m and a 10-m crater produced by 

chemical explosives in dense basalt flows at the Nevada 

Test Site (Vortman and others, 1960, Shot 11). When 

the resolution is 22 em (fig. 57A), a great number of 

blocks are visible in and around both the large and 

small craters. When the resolution is 85 em (fig. 57B), a 

few large blocks are visible and smaller ones appear as 

lumps. 

When the requirements given are taken into account, 

an assessment of the surface and subsurface peoperties 

can be made. For example, the highest resolution (26 

em) images of Ranger IX (fig. 58) clearly show craters 

down to a metre in size. On the images, fresh craters 

down to 1 m across have continuous raised rims and 

large depth-to-diameter ratios characteristic of soillike 

materials with low cohesions and densities near 1.6 

g/cm3. Larger fresh craters do not contain blocks, nor is 

the surface near the crater littered with many blocks 

larger than 26 em. The near-surface materials imaged 

by Ranger IX are soillike with a grain size substantially 

less than 26 em. Slopes of small crater walls are from 32° 

to 38° (Choate, 1966), implying that the angle of internal friction is near that for cohesionless terrestrial soils. 

RANGER AND OTHER IMPACTS 

Predictions of the sizes of the craters produced by the 

impacts of Ranger spacecraft, SIVB stages of Apollo, 

and Lunar Module Ascent Stages were made using 

missile impact data. Craters produced by the impact of 

Ranger spacecraft were estimated to be 12.2 ± 3 m 

(letter to I. G. Recant and T. P. Hansen, Lunar Orbiter 

Project Office, Dec. 10, 1965), craters produced by the 

impact ofSIVB stages of Apollo, 57± 17m, Ascent stage 

craters, 4 ± 2 m across (Latham and others, 1970). 

Craters produced by Ranger spacecraft (fig. 59) turned 

out to be near 13 to 15m (Whitaker, 1972 ; Moore, 1972), 

SIVB impact craters near 40 m across (Whitaker, 1972). 

An overestimate of the size of SIVB craters may have 

resulted from not taking into account the bulk density of 

the SIVB, which was very low (for effect of projectile 

density, see Moore and others, 1965; Birkhoff and 

FIGURE 57 .-Effect of resolution on appearance of craters formed in 

rock. Large crater in center about 33 m across, small one at lower 

left is about 10m across. A, Identification resolution near 22 em. B , 

Identification resolution near 85 em. 

FIGURE 58.-Last B-camera frame of Ranger IX (B-88) showing 

rimmed fresh craters down to 1 m across with raised rims. Distance 

between reticles about 40 m; identification resolution near 26 em. 

Arrow indicates 1-m, fresh-rimmed crater indicating low cohesion 

of surface material. Note general absence of large blocks around 

larger craters, indicating materials are unlike dense basalt flows. 

others, 1948). The small crater size predicted for the 

impact of the Ascent Stages, when compared with the 

size predicted by Whitaker (1972), result from the small 

angle of impact, an effect Whitaker neglected. 

SURVEYOR IMAGES 

Data on phenomena associated with missile impacts 

have been used to account for observations made using 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B37 

Surveyor images, in particular interpretations of fresh 

craters and their ejecta were used to assess the nature of 

surface and near-surface materials at the Surveyor I 

Landing site (Rennilson and others, 1966). For Surveyors VI and VII (Shoemaker, Morris, and others, 

1969), low-velocity secondary impacts were identified 

by analogy with similar features around missile impact 

craters (compare fig. 60 with figs. 18 and 22). 

PASSIVE SEISMIC EXPERIMENT 

Data on amplitudes of the initial seismic signal 

produced by missile impacts were a useful guide for 

predicting amplitudes of initial seismic signals (Pwave) produced by impact on the lunar surface. The lack 

of similarity of subsequent seismic signals points up the 

large differences between the structure of terrestrial 

and lunar rocks (Latham and others, 1970). 

APOLLO ORBITAL PHOTOGRAPHS 

A number oflunar craters photographed from orbit by 

the Apollo missions to the Moon are similar to missile 

impact craters in their morphologies but larger. Some of 

these lunar craters exhibit striking bilateral symmetry 

similar to that of Crater 7 (Moore, 1971a, fig. 2-34); 

others yield evidence for inverted stratigraphy (Moore, 

1971b, fig. 2-31). One crater photographed by Apollo 16 

is quite similar to missile impact craters in that little or 

no ejecta is found on the up-trajectory side of the crater 

while lighter ejecta, including large blocks, is found in 

lateral and down-trajectory directions (fig. 61). Data on 

missile impact craters in cohesive targets has contributed to establishing an empirical relation between 

diameters of largest blocks ejected from craters and 

crater diameters (Moore, 1971b, 1972). 

ASTRONAUT TRAINING 

The principal use of missile impact craters in the 

training of astronauts was to establish in their minds 

how lunar impact craters could be used to obtain samples from beneath the lunar regolith and to train them 

to recognize features that were expected in small lunar 

craters. Impact craters are natural drill holes in the 

local materials, and samples from beneath the surface 

can be collected on their rims and flanks (see 

Shoemaker, 1960). Samples from rims of progressively 

larger craters yield samples from progressively greater 

depths. This principle was employed on all Apollo 

missions. For example, some ofthe fragments collected 

at the Apollo 11 site were derived from West crater (180 

m diameter), 400 m east of the Apollo 11 site (Shoemaker, Bailey, and others, 1969); Apollo 12 astronauts 

made a conscious effort to examine craters of various 

sizes (Shoemaker and others, 1970); and collection of 

samples from large craters 340 to 900 m across were 

FIGURE 59.-Craters produced by Ranger impacts. A, Impact crater 

made by Ranger VII. Crater near 14m across (Apollo 16 Panoramic 

Camera frame 5420). B, Impact crater made by Ranger VIII (Lunar 

Orbiter II, photograph H 70, framelets 601 and 602). Crater is 13.8 

by 13 m. C, Impact crater made by Ranger IX. Crater near 14m 

across. (Apollo 16 Panoramic Camera frame 4658.) 
B38 CONTRIBUTIONS TO ASTROGEOLOGY 

FIGURE 60.-A, Secondary impact crater about 3m in diameter near 

Surveyor VII (compare with fig. 22). Projectile smaller than crater it 

produced. B, Secondary impact crater on lunar surface near Surveyor I for which projectile fills crater (compare with fig. 18). 

prime goals for Apollo 14 and 16 astronauts (Swann and 

others, 1971; Muehlberger and others, 1972). 

The nature of asymmetry of craters and ejecta was 

also used to help identify secondary craters. 

LUNAR SAMPLES 

Ejecta from missile impact craters is similar to ejecta 

from lunar craters. In particular, undeformed blocks 

and fragments of ejecta occur along with sheared and 

compressed fragments with grooves and striations as 

well as rocks with coated surfaces (fig. 62). Sample 

1404 7 (fig. 62A) is an example of sheared lunar regolith 

material collected from the west rim of a sharp 5-

m-diameter crater at station B of the Apollo 14 site. This 

sample was a clod of regolith material partly bounded 

by planar surfaces that were grooved and striated 

(Swann and others, 1971, p. 74-75) like fragments in the 

ejecta from missile impact craters (fig. 25). The planar 

surfaces of 14047 (Swann and others, 1971, p. 75, fig. 

3-35) are similar to some fragments in the ejecta from 

missile impacts, units bounded by fractures in shattered 

and fractured material (fig. 14), and units bounded by 

fractures in the zone of conjugate fractures (fig. 31). 

Many fragments collected on the Moon have surfaces 

coated with glass and pulverized, partly melted debris 

like material collected at the Apollo 17 (Apollo Lunar 

Geology Investigation Team, 1973, p. 63; fig. 62B) and 

14 sites (Swann and others, 1971; fig. 62C). Many of 

these coatings have been injected along fractures (fig. 

62B,C) and contain metal particles in glass (Wosinski 

and others, 1972; fig. 62C). Similar coatings are found 

on fragments of sheared surfaces of compressed target 

· material (fig. 25), along some conjugate fractures (fig. 

14), to· a lesser extent on tensile fractures normal to 

grooved and striated surfaces. Much of the coating on 

fragments from missile impact craters is powdered and 

disaggregated projectile material but it is also, in part, 

fused metal and vesiculated material from the missile. 

Impact cratering accounts for the coated rocks on the 

lunar surface, especially those concentrated on the 

flanks of small craters. 

Injections of clastic debris along fractures are found in 

lunar samples (Wilshire and others, 1973). In one such 

rock, shown in figure 62, mobilized white clastic debris 

fills fractures within shattered darker gray rock; in 

some respects similar to the cataclastic injection in 

rocks shown in figure 29. 

FIGU RE 61.- Apollo 16 Panoramic Camera photograph showing 

oblique view of2-km-diameter crater. South is toward top of picture. 

Note asymmetrical ejecta, exposures, and talus of dark material on 

up-trajectory wall, and large blocks on lateral and down-trajectory 

flanks (AS-16 Panoramic Camera frame 4511). 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B39 

0 2cm 

A 

FIGURE 62.- Lunar samples similar to ejected fragments around 

missile impact craters. A, Sheared and compressed regolith breccia 

collected at Apollo 14 site. Note grooves and striations on right side 

of rock (compare with fig. 25A ). Apollo 14 sample 14047.B, Regolith 

breccia collected at Apollo 17 site with coating of glass on planar 

fracture surface. Glass injected along fracture (compare with figs. 

25B , D , and 14). Apollo 17 sample 70295. C, Glass vein injected 

along fracture (lower left edge of rock) in breccia collected at Apollo 

14 site. Glass vein has metallic inclusions. Apollo 14 sample 14306. 

D , Breccia collected at Apollo 161anding site. Thin white stringers 

are clastic injections (see fig. 29). Apollo 16 sample 61015. 

SUMMARY AND CONCLUSIONS 

Craters produced by the impact of missiles with 

natural materials along oblique trajectories have 

bilateral symmetry across the plane of the trajectory. 

The degree to which the symmetry is developed is a 

function of crater size, target material, and missile 

trajectory. Local steep slopes modify or destroy the 

symmetry. Typically, crater rims are highest on lateral 

and down-trajectory sides of the crater; steep crater 

walls are found on the up-trajectory side of the crater. 

Crater symmetry yields some information on the direction of origin of the missile. 

For most missile impact craters, seven mappable 

units are exposed in and around the craters, generally 

bilaterally symmetrical across the plane of the 

trajectory. Winds, local slopes, and heterogeneity of the 

target material may alter the symmetry. Near the 

craters, thick ejecta composed of very fine to coarse 

debris blankets the uplifted original ground surface on 

the lateral and down-trajectory flanks of the crater. For 

layered targets, the original sequence of layering is 

preserved but inverted in the thick ejecta. Concentration and thickness of ejecta decrease outward in lateral 

and down-trajectory directions, becoming thin to 

discontinuous and then scattered. Up-trajectory, 

ejecta is usually absent, thin to discontinuous, or 

0 2cm 

scattered on the surface, but it may be thick in some 

cases. Some fragments are ejected as far as 330 m from 

the crater. Within the crater, slope material composed 
B40 CONTRIBUTIONS TO ASTROGEOLOGY 

of talus and fallback partly cover crater walls and cover 

crater floors. Locally, tilted and broken target material 

may be exposed in upper crater walls on the lateral and 

down-trajectory sides of the crater. For most craters, 

shattered and fractured target material is exposed on 

the up-trajectory crater wall and open fractures concentric to the crater edge are exposed on the level or 

even downwarped up-trajectory flank. 

Most of the ejecta are fragments of target material, 

disaggregated target material, and crushed target 

material. The larger fragments are relatively uncleformed. For porous targets, significant amounts of the 

ejected fragments have been deformed by shearing and 

compression of the target material. Some sheared and 

compressed fragments have surfaces coated with a dark 

mixture of fragmented, powdered, and partly fused 

missile. 

When the surface materials around missile impact 

craters have low cohesion and large fragments are 

ejected from the crater, a great number of secondary 

impact craters are produced. The distribution of the 

secondary impacts has bilateral symmetry when the 

surrounding surface is uniform. A continuous spectrum 

of secondary craters is produced. Near the crater ejected 

fragments may be larger than the crater they produce or 

about the same size. Farther from the crater, secondary 

fragments deform, break up, and partly fill secondary 

craters that are larger than the fragment. At greater 

distances, secondary fragments are smaller than the 

craters they produce and are completely ejected from 

the crater. 

Subsurface deformation of the target ma~erial is 

complex. A breccia composed of a mixture of fragmented 

and powdered missile and sheared and compressed 

target material underlies the crater floor. For craters in 

fixed gypsum dunes, a sanded zone with flow banding 

surrounds the mixed breccia on the down-trajectory and 

lateral sides of the breccia. Cataclastic injections of 

mixed projectile pieces and target material from the 

mixed breccia penetrate into the sanded zone. In alluvium, a breccia with no missile pieces surrounds the 

mixed breccia. A zone of conjugate fractures surrounds 

the central breccias and sanded material. Near the 

surface beneath the down-trajectory and lateral flanks 

of the crater, the target material is tilted upward and 

broken. Beneath the up-trajectory flank, open fractures 

are found. In the ejecta, fragments are found that have 

the same properties as the fragments in the subsurface 

deformation zones. For layered targets, materials from 

lower layers are displaced upward in the mixed breccia 

and rather complex folding may occur beneath the crater rim. 

Missile or projectile behavior and deformation during 

impact is chiefly a function of target material and 

projectile velocity although there are other variables. 

At low velocities, projectiles are slightly deformed, 

whereas at velocities exceeding 3.9 km/s, they are 

fragmented into very small pieces, powdered, and fused. 

Where targets are porous, the missile or fragmented 

missile tends to remain completely or partly below the 

surface, particularly at the lower velocities; where 

dense and coherent, the missile or pieces of it tend to 

remain above the surface as ejecta. 

Linear dimensions of the missile impact craters are 

proportional to the 0.412 to 0.445 power, while displaced 

masses are proportional to the 1.205 to 1.298th power of 

kinetic energy. Extrapolation of data on displaced 

masses and energies ofhypervelocity impact craters in 

rock and sand converge and intersect the missile impact 

data at kinetic energies near 1015 to 1016 ergs. 

There are a number of parallels between craters 

produced by chemical explosives and missile impacs: 

(a) they are about the same size when the scaled depth of 

burst ofthe explosive is small and the TNT energy of the 

explosive is equivalent to the kinetic energy of the 

missile; (b) craters produced in water-saturated targets 

are larger than their dry counterparts; (c) their size is 

dependent on target material; (d) both types of craters 

commonly have mixed breccia beneath their floors; 

(e) both have sheared and compressed target material 

in their ejecta when the target is porous; (f) they have 

similar fracture patterns and deformations; and (g) the 

original stratigraphy or sequence of layering is preserved overturned in the ejecta near the flank and rim. 

Some problems concerning impact craters are unresolved: (a) the effect of impact angle on the size ofthe 

crater is not clear and may vary with target and projectile properties; (b) the equivalent scaled depth of 

burst of an impact event clearly varies with projectile 

and target properties in a manner not entirely understood; (c) energy and velocity thresholds for cratering are not clearly defined; and (d) the relation between 

crater size and missile properties is not entirely resolved because of the large number of variables in target 

material and projectile conditions at impact. 

Compression of porous target materials is expected, 

as some missile velocities are sufficient to produce shock 

pressures of several hundred kilobars, and experimental data on shock-wave compression of porous materials 

indicate significant compression may occur at pressures 

near 5 to 10 kbar and greater. The large size of craters 

in water-saturated targets probably results from low 

effective target strengths produced by positive pore 

pressures during shock compression of the target. 

Data on craters produced by chemical and nuclear 

explosives with shallow depths of burial provide the 

basis for best estimates of energies of large natural 

hypervelocity impact craters. 
MISSILE IMPACT CRATERS, NEW MEXICO, AND APPLICATIONS TO LUNAR RESEARCH B41 

The study of craters produced by missile impacts has 

contributed to lunar science in many ways: (a) the 

character of their ejecta and shape was used to assess 

some of the properties of lunar surface materials; 

(b) they were used to predict sizes of craters produced by 

artificial impact on the Moon; (c) certain features 

photographed by Surveyors were found to be consistent 

with similar features around missile impact craters, 

(d) missile impacts were used to help calibrate the 

Apollo Passive Seismic Experiment, (e) many craters 

seen in Apollo orbital photographs were found to be 

morphologically and geologically similar to missile 

impact craters, (f) data on missile impact craters and 

their ejecta were used to help train astronauts in 

recognizing certain features of lunar craters and in 

collecting samples; and (g) fragments ejected from 

missile impact craters were found to have properties 

similar to fragments collected on the lunar surface. 

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Crater 

No. 

3 

4 

6 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

Target 

Material 

Fine sand iSPI, uniform, light 

brown, nonplastic cohesion- less to weakly cohesive, dry to moist Sandstone !rock), fine- to 

medium-grained, nonplastic, 

sorted, light tan, indurated, 

dry 

Silt IMLI, very pale orange, 

LL-30, PL-25; low cohesion, 

dry to moist Silty fine sand iSM), paleyellow-brown, nonplastic 

fines, low cohesion, dry to 

moist 

Silty fine sand (SMI, paleyellow-brown, nonplastic 

fines, low cohesion, dry to 

moist 

Silt, sandy IMLI, mod. orangepink LL-32, PL-24, low cohesion, 

dry to moist Coarse-silty to clayey sand, 

crystalline well-graded 

iSM-SCi, very light gray cohesive LL-20, PL-17, water saturated, water to = 30<:·o, 

gypsum lake beds Silt iMLI, very pale orange, low cohesion, dry to moist Sandstone (rock!, mediumgrained(?), light tan, nonplastic indurated, dry 

Sand, silty iSMI, well-graded, 

pale reddish brown, LL-26, 

PL-25, low cohesion, dry to 

moist 

Clay, sandy (CLI, light gray, grains of gypsum, LL-14, 

PL-28, high cohesion, moist Silt IMLI, pale-yellow-brown, 

LL-34, PL-32, cohesion low, water 4.9 percent Sand ISPI, fine-grained, uniform, light brown, very low cohesion, dry to moist Clay, sandy iCLi, light gray, 

grains of gypsum, LL-14, PL-28, 

high cohesion, moist, lake beds 

Clayey silts IML), pale yellow, 

brown, LL-27, PL-26, low cohes- ion, dry to moist 

Sand, gravelly, silty (SMI, 

pale yellow, brown, LL-27, 

PL-23, low cohesion, dry to 

moist 

Silts and very fine sand iCLMLI, grayish-orange, LL-18, 

PL-14, low cohesion, dry to 

moist gypsiferous over sandy 

silt IMLI, uniform pale-yellowbrown, LL-32, PL-23, high cohesion, dry to moist fixed gypsum dune Sandy silt IMLI, uniform, paleyellow-brown, LL-32, PL-23, 

high cohesion, dry to moist, fixed 

Clayey silt IMLI, very pale orange, LL-30, PL-25, moderate cohesion, water 12%, moist Clayey silt IMLI and silty clay, 

pale-yellowish-brown, LL-43, 

PL-40, moderate cohesion, water 6--10% 

Geology 

Dune 

Sandstone 

Soil 

Alluvium 

Alluvium 

Alluvium 

Gypsum 

Alluvium 

Sandstone 

Alluvium 

Gypsum 

lake beds 

Alluvium 

Dune 

Gypsum 

Jake bed 

Colluvium 

Colluvium 

Alluvium 

Fixed 

gypsum 

dune 

TABLE 3.-Data on missile impacts-lithologic description and physical parameters 

Density 

g/cm3 

1.6 

2.5 

1.1 

1.4 

1.4 

1.4 

1.2-1.6 

1.45 

=2.5 

1.5 

1.98 

1.21 

1.55 

1.98 

1.16--1.34 

1.33-1.4 

1.42-1.46 

1.40-1.44 

1.33 

1.9--2.1 

Projectile 

Kinetic 

energy, 

1014ergs 

3.62 

5.72 

6.51 

5.92 

4.58 

13.8 

15.7 

4.23 

5.70 

2.95 

5.92 

5.21 

6.63 

2.65 

24.1 

31.4 

19.7 

24.1 

20.7 

25.2 

Impact 

angle, (0) 

56.2 

56.8 

50.4 

50.4 

51.4 

46.4 

45.9 

56.2 

56.2 

56.8 

51.0 

51.0 

51.0 

56.6 

45.7 

45.0 

45.0 

45.7 

46.0 

45.8 

Apparent 

depth 

da, 

em 

85 

76 

49 

58 

55 

98 

198 

61 

=61 

61 

82 

76 

85 

61 

150 

160 

140 

160 

159 

177 

Apparent 

radius 

ra, 

em 

120 

160 

114 

123 

112 

220 

402 

102 

=140 

98 

146 

115 

122 

112 

259 

280 

266 

255 

278 

312 

Crater 

Rim Rim 

radius height 

rr, 

em 

137 

172 

126 

164 

125 

238 

463 

113 

=140 

110 

180 

125 

137 

150 

281 

314 

317 

314 

304 

360 

h, 

em 

25 

18 

40 

48 

11 

23 

12 

23 

29 

31 

27 

27 

32 

31 

Apparent 

volume 

Fa, 

106 cm3 

1.55 

1.37 

1.05 

1.60 

1.23 

7.68 

46.1 

1.81 

2.0 

(est.) 

.78 

2.27 

1.68 

1.34 

.90 

13.5 

17.1 

16.4 

17.7 

15.4 

18.1 

Mapping 

Displaced 

mass Mappers Md. 106 grams 

2.47 H. J. Moore SP/4 G. Hensz 

3.42 H. J. Moore Lt. B. Hughes 

1.16 R. Kachadoorian 

2.24 R. Kachadoorian 

1.72 R. Kachadoorian 

10.8 H. J. Moore 

H. Wilshire 

73.8 H. J. Moore 

H. Wilshire 

2.62 R. Kachadoorian 

W. Quaide 5.0 R. Kachadoorian (est.) W. Quaide 

1.17 H. J. Moore R. Kachadoorian 

4.50 H. J. Moore 

R. Kachadoorian 

2.03 R. Kachadoorian 

H. J. Moore 

2.08 R. Kachadoorian 

H. J. Moore 

1.78 H. Holt P. Margolin 

17.0 H. J. Moore 

R. Kachadoorian 

23.0 H. J. Moore 

R. Kachadoorian 

24.0 H. J. Moore 

25.0 H. J. Moore 

20.5 H. J. Moore 

D. Cummings 

36.0 H. J. Moore 

H. Holt 

Photographs 

Date White Sands Nos. and others 

4/64 29-040-2296-2651 to 2653 AFMDC, and aerials 

4/64 29-040-1917-2473 to 2478 

AFMDC and aerials 

2/64 AFMDC 

2/64 AFMDC 

2/64 AFMDC 

7/64 AFMDC 

8/64 29-040-4084-5284 to 5290 AFMDC and aerials 

11/64 None 

11/64 None 

11/64 None 

1/65 Unclassified negatives held by U.S. Geological Survey 

2/65 None 

2/65 29-040-0382-2535, 39, 41 

5/65 29-040-3152-6194 to 6219 

5/65 29-040-3153-6157 to 6176 

6/65 29-040-3154-6177 to 6193 

6/65 29-040-3155-6561 to 6572 

10/65 29-040-5099-11024 to 11043 

10/65 29-040-5099-11044 to 11063 

ttl 

~ 

~ 

Q 

0 

z 

>-3 

:::0 

53 

e 

>-3 

0 

z 

rn 

>-3 

0 

> rn 

>-3 

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0 

Q 

M 

0 

L' 

0 

Q 

-< 
Crater 

No. 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

31 

32 

33 

34 

35 

36 

37 

38 

39 

40 

41 

42 

43 

Target 

Material 

Sandy silt <MLl, grayish-red, 

LL-34, PL-30, low cohesion, 

water= 3% Sandstone(?! (rock), dry 

Limestone(?) (rock), dry 

Silty fine sand <SMl, uniform, to well-graded in upper part, 

LL-25, PL-25, sandy silt (MLl, 

nonplastic in lower part. light 

brown, low cohesion in upper part, moderate cohesion in lower part, water 2-7 percent 

Silty sand \SMl, and silty, 

clayey sand ( SC l, light to moderate brown, LL-23, PL-20, moderate cohesion, dry to moist Sand, dune 

Not sampled but like crater 6 

Sandy silt (MLl, uniform, paleyellow-brown, LL-32, PL-23, 

high cohesion, water 1-6 percent 

Sandy silt (MLl, uniform, paleyellow-brown, LL-32, PL-23. high 

cohesion, water 1-6 percent 

Sandy silt <MLl, uniform, paleyellow-brown, LL-32, PL-23, high cohesion, water 1-6 percent 

Sand, silty (SM), well-graded, 

light brown, nonplastic fines, low cohesion, water 5 percent 

Sand, silty (SMl. well-graded 

light brown, nonplastic fines, low cohesion, water 4 percent 

Sand, silty (SM!, well-graded, 

light brown, nonplastic fines, some boulders brought to sur- face, low cohesion, dry to moist Not sampled but like crater 6 

Silt (MLl, pale-yellow-brown, 

nonplastic, low cohesion, dry to moist, overlying very pale orange sand (SMl, nonplastic 

~:ded~IJ~s:od ~~a~f:t~~~;:eesl_l- ion, water 6 percent Silt (ML), pale-yellow-brown, 

nonplastic, overlying very pale orange sand (SM), nonplastic fines composed of gypsum, well- graded, low to moderate 

cohesion, water 2-6 percent 

Sandy silt (MLl, uniform, paleyellow-brown, LL-32, PL-23, high 

cohesion, water 1-6 percent 

Sandy silt (ML), uniform, paleyellow-brown, LL-32, PL-23, high 

cohesion, water 1-6 percent 

Sandy silt (ML), uniform, paleyellow-brown, LL-32, PL-23, high 

cohesion, water 1-6 percent 

Sandy silt (ML), uniform, paleyellow-brown, LL-32, PL-23, high 

cohesion, water 1-6 percent 

Sandy silt (ML), uniform paleyellow-brown, LL-32, PL-23, high 

~~~ed~ ~it(~w. ~~a::~::trown, LL-36, PL-::31, low cohesion, dry to moist Silt (ML), pale-yellow-brown 

nonplastic, low cohesion, dry to moist 

TABLE 3.-Data on missile impacts-lithologic description and physical parameters -Continued 

Geology 

Soil and colluvium 

Rock 

Rock 

Sandalluvium 

Dune 

Alluvium 

Fixed 

gypsum 

dune 

Fixed 

gypsum 

dune 

Fixed 

gypsum 

dune 

Alluvium 

Alluvium 

Alluvium 

Alluvium 

Alluvium 

Alluvium, 

gypsum 

lake beds 

Fixed 

gypsum 

dune 

Fixed 

gypsum 

dune 

Fixed 

gypsum 

dune 

Fixed 

gypsum 

dune 

Fixed 

gypsum 

dune 

Colluvium 

Gypsiferous 

alluvium 

Density 

g/cm3 

1.7-1.8 

=2.5 

=2.7 

1.64-1.81 

1.74-2.03 

1.4 (est) 

1.37-1.56 

1.37-1.56 

1.37-1.56 

1.56-1.77 

1.56-1.77 

1.56-1.77 

1.4 (est) 

1.42 

1.42 

1.37-1.55 

1.37-1.55 

1.37-1.56 

1.37-1.56 

1.47-1.51 

1.2-1.5 

1.4 

Projectile 

Kinetic 

energy, 

1014ergs 

2.10 

2.90 

2.90 

25.1 

25.1 

25.1 

13.5 

15.8 

15.8 

15.8 

20.4 

20.4 

20.4 

20.7 

13.5 

13.5 

16.0 

16.0 

16.0 

16.0 

81.0 

13.8 

16.5 

Impact 

angle, (0) 

58.0 

58.0 

58.0 

45.8 

45.8 

45.8 

47.8 

47.0 

47.0 

47.0 

46.4 

46.4 

46.4 

46.2 

47.8 

47.8 

48.0 

48.0 

47.0 

47.0 

42.3 

48.0 

47.0 

Apparent 

depth 

da, 

em 

70 

Tis 

171 

134 

116 

119 

107 

104 

127 

131 

94 

152 

97 

88 

121 

136 

140 

188 

122 

64 

Apparent 

radius 

ra, 

em 

125 

265 

256 

182 

233 

215 

182 

237 

226 

210 

270 

220 

231 

252 

224 

249 

350 

210 

144 

Crater 

Rim Rim 

radius height 

rr. 

em 

165 

=50 

305 

286 

199 

257 

257 

206 

279 

257 

255 

312 

251 

259 

286 

283 

281 

400 

236 

182 

h, 

em 

26.0 

16 

13 

21 

38 

28 

16 

23 

23 

=36 

18 

24 

33 

40 

17 

32 

15 

19 

Apparent 

volume 

Va, 

106 cm3 

1.49 

13.4 

8.30 

5.50 

11.0 

6.98 

5.20 

9.49 

10.9 

8.27 

13.6 

6.03 

6.84 

10.7 

9.86 

14.4 

33.9 

9.33 

1.38 

Mapping 

Displaced 

mass Mappers Md. 106 grams 

2.61 H. J. Moore 

R. Kachadoorian H. Holt Not mapped Estimated from photograph 23.1 H. J. Moore H. Holt J. M'Gonigle 

15.7 H. J. Moore J. M'Gonigle 

Not mapped 7.70 D. Cummings D. Gault 16.1 H. J. Moore D. Cummings 

10.3 H. J. Moore D. Cummings 

7.65 H. J. Moore D. Cummings 

15.8 H. J. Moore N.J. Trask 

18.1 H. J. Moore 

N.J. Trask 

13.6 H. J. Moore N.J. Trask 

19.0 J. D. Crossen 

J. M'Gonigle Cross section 

8.58 H. J. Moore J. F. McCauley 

9.99 H. J. Moore 

R. Kachadoorian 

15.6 H. J. Moore R. Kachadoorian 

14.4 H. J. Moore J. F. McCauley 

21.1 H. J. Moore J. F. McCauley 

50.5 H. J. Moore J. F. McCauley 

13.5 H. J. Moore J. F. McCauley 

1.59 H. J. Moore G. Ulrich T. Offield 

Photographs 

Date White Sands 

Nos. and others 

1/66 29-040-0268-1120 to 1139 

29-040-0268-1140 to 1142 29-040-0268-1143 to 1147 

6/66 29-040-2984-6326 to 6364 

6/66 29-040-2988-6323 to 6381 

29-040-2167-6325 to 6367 

7/66 29-040-3277-7535 to 7538 

7/66 29-040-3277-7526, 27 29-040-5106-10880 to 10882 

7/66 29-040-3277-7532 to 7534 29-040-5106-10876 to 10883 

7/66 29-040-3277-7530, 31 29-040-5106-10878 to 10886 

10/66 29-040-5108-10837 to 10862 

10/66 29-040-5108-10839 to 10859 

10/66 29-040-5108-10838 to 10860 

10/66 29-040-5112-10891 to 10909 

29-040-0964-2769 to 2803 

3/67 29-040-0964-2793 to 2811 

3/67 29-040-1059-3956 to 3987 

3/67 29-040-1059-3958 to 3978 

6/67 29-040-2632-5836 to 5841 29-040-2986-6202 to 6213 

6/67 29-040-2632-5827 to 5843 

6/67 None 

6/67 29-040-2631-5809 to 5815 

9/67 29-040-4506-9774 to 9797 

~ 

w 

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Target 

Crater Material No. 

44 Silt, sandy to clayey <NLI, 

yellowish brown, layered, LL-31 

to 38, PL-20 to 32, plasticity low to medium, moderate to low 

cohesion. water saturated. moist to 30 percent 

45 Sandy clay (CLI, pale-yellowbrown, LL-34, PL-16, moderate 

46 cohesion, water 6--7 percent Sand iSWl, uniform, grayish 

orange-pink, very low cohesion, 

water 0--6 percent 

47 Sand iSWI, uniform grayish 

orange-pink, very low cohesion, water 0--6 percent 48 Clay, sandy (CL\, light gray. gypsum, LL-14, PL-28, high 

cohesion, water 7-13 percent 

49 Sand, silty iSMi, pale reddish- brown, nonplastic fines, low cohesion, water 0--5 percent 

50 Silt IMLI, very light gray, LL-35, PL-28, high cohesion, water 7-13 percent 51 Silt IMLI, very light gray. 

LL-35, PL-28, high cohesion, 

water 7-13 percent 

52 Silt iMLI, very light gray, 

LL-35, PL-28, high cohesion, water 7-13 percent 

53 Sand, silty iSM\, light brown, 

uniform, nonplastic fines, moderate cohesion, water 3.2 percent 

54 Clay, sandy iCL\, very pale 

orange, LL-20, PL-18, moderate 

55 cohesion, water 4.6 percent 

Clay, sandy iCLI, pale yellow 

brown, nonplastic, moderate 

56 cohesion, water 2.6 percent Sand (SP\, fine-grained, uniform, very pale orange, very low 

57 cohesion, water 0--3 percent Not sampled but like crater 15 

58 Sand, silty iSM\, well-graded, 

some boulders and cobbles 

59 brought to surface Not sampled but like crater 6 60 Not sampled but like crater 6 

TABLE 3.-Data on missile impacts-lithologic description and physical parameters- Continued 

Projectile Crater Mapping 

Kinetic Impact Apparent Apparent Rim Rim Apparent Displaced 

Geology Density energy, angle, depth radius radius height volume mass Mappers g/cm3 1014ergs n da, ra, rr. h, Va. Md, em ern em em 106 cm3 106 grams 

Gypsum 1.85 44.6 25.1 218 486 562 43 83.4 154.0 H. J. Moore 

lake G. Ulrich 

beds T. Offield 

Alluvium 1.36 14.4 47.5 155 265 284 21 11.3 15.4 H. J. Moore R. Kachadoorian P. Margolin 

Gypsum 1.35 14.4 47.5 152 242 283 18 9.33 12.6 H. J. Moore 

dune R. Kachadoorian P. Margolin 

Gypsum 1.35 14.4 47.5 152 250 301 15 13.6 18.3 H. J. Moore 

dune R. Kachadoorian P. Margolin 

Gypsum 1.98 (est. 1 6.45 34.8 88 144 164 12 2.62 5.19 H. J. Moore 

lake P. Margolin 

beds 

Alluvium- 1.54 2.09 60.6 52 109 125 9 1.02 1.57 H. J. Moore 

colluvium P. Margolin 

Gypsum 1.85 23.2 46.2 179 308 370 55 25.9 48.0 H. J. Moore lake 

beds E: Woa~3olin 

Gypsum 1.80 24.1 46.2 189 326 368 58 27.1 48.7 H. J. Moore 

lake P. Margolin 

beds L. Youd 

Gypsum 1.80 23.5 46.2 192 335 369 40 29.1 52.4 H. J. Moore 

lake H. Wilshire 

beds S. Kieffer 

Alluvium 1.5--1.6 69.6 40.6 194 328 368 15 24.1 38.6 H. J. Moore R. Kachadoorian S. Kieffer 

Alluvium 1.5--1.6 13.5 52.0 69 174 200 29 3.16 4.86 H. J. Moore 

H. Wilshire 

Alluvium 1.6--1.7 14.5 52.0 84 172 199 19 3.27 5.23 H. J. Moore 

H. Wilshire 

Gypsum 1.4 73.5 36.5± 5 290 470 506 30 97.5 136.0 H. J. Moore 

dune S. Kieffer 

Alluvium 15.8 47.0 88 205 =25 Not mapped 

Colluvium =2.0 50.0 35.0 140 286 315 8 13.9 27.8 H. J. Moore R. Kachadoorian 

Alluvium 1.4 (est.\ 13.5 47.8 116 214 Not mapped 

Alluvium 1.4 (est.) 13.5 47.8 76 214 Not mapped 

Photographs 

Date White Sands Nos. and others 

9/67 Seven, no numbers 

11/67 29-040-5931-11466 to 11483 

11/67 29-040-5831-11464 to 11478 

11/67 29-040-5831-11465 to 11484 

11/67 None 

3/68 29-040-1181-3164 to 3179 

6/68 29-040-2947-6143 to 6157 

6/68 29-040-2947-6143 to 6157 

11/68 29-040-C-5578-10330 to 10344 

1/69 29-040-C-0214-1387 to 1404 

4/69 Not numbered 

4/69 Not numbered 

6/69 29-040-C-2627-4732 to 4749 

24-040-C-3277-7528, 29, 

29-040-5106-10885 1/73 29-040-0031-0164 to 0180 

29-040-3277-7535 to 7538 

29-040-3277-7535 to 7538 

to 

t+:>-

O':l 

0 

0 

z 

1--3 

::0 

53 

c 

1--3 

0 

z 

rn 

1--3 

0 

> rn 

1--3 

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0 

0 

M 

0 

r-' 

0 

0 

~ 
TABLE 4.-Data on explosive craters-lithologic description and physical parameters 

Target Explosive Crater 

Density Charge Depth of Scaled Apparent Apparent Rim Rim Apparent Crater Material weight, Energy, burst depth of dda~h p radius radius height volume lbs No. burst g/cm3 <TNT 1014 ergs dob, ra, rr, h, Va, 

equiv.l ft ft?ib ~:' em em em em 106 g 

- ---~-- -

43--1 Silt (MLI, pale yellow brown, 1.4 100 17.7 1.31 0.29 92 187 219 15 3.77 nonplastic, low cohesion, 1931 dry to moist 43--2 50 8.8 1.31 .36 52 176 195 11 2.29 1471 

43--3 50 8.8 .66 .18 56 145 175 7 1.40 147) 

49-1 Sand, silty iSMJ, pale reddish 1.5 5 .88 .83 .5 46 101 113 2 .55 brown, nonplastic fines, low 14.661 cohesion, water (}...5 percent 

49-2 10 1.77 .54 .25 58 105 130 9 .82 (9.32) 

49-3 10 1.77 1.08 .51 58 115 143 13 1.26 19.321 

49-4 10 1.77 2.17 1.03 92 149 163 7 2.71 19.321 

49-5 20 3.54 1.33 .5 79 151 176 13 2.79 118.61 

49-6 5 .88 .83 .5 44 94 114 6 .58 (4.661 

L-7 Sand, clayey ISCI, pale 1.54 20 3.54 1.58 .6 71 145 176 16 2.81 reddish brown, plastic fines, (18.6) 

low cohesion, colluvium L-8 Silt, clayey IMHI, pale 2.07 75 13.3 1.31 .32 96 199 229 -9 6.20 reddish brown, LL-53, PL-39, (69.91 low cohesion, alluvium 

Mapping 

Displaced mass Mappers Md, 

106 g 

5.28 H. J. Moore 

G. Ulrich G. Offield 

3.21 H. J. Moore G. Ulrich T. Offield 

1.96 H. J. Moore G. Ulrich T. Offield 

.85 H. J. Moore P. Margolin 

1.26 H. J. Moore P. Margolin 

1.94 H. J. Moore 

P. Margolin 

4.17 H. J. Moore P. Margolin 

4.30 H. J. Moore P. Margolin 

.89 H. J. Moore P. Margolin 

4.33 H. J. Moore 

R. Kachadoorian 

12.83 H. J. Moore 

R. Kachadoorian 

Date 

9/67 

9/67 

9/67 

3/68 

3/68 

3/68 

3/68 

3/68 

3/68 

2/68 

2/68 

Photographs 

White Sands Nos. 

and others 

29-04(}...4506 

9974 to 9977 9979 to 9982 

9984, 9985 9987, 9990 

9992 to 9997 

None 

None 

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GPO 690-250