1980LPSC...11.2075G jectile experiments, either transient R. of ejecta. estimates gravity tion the were whereas unusual progressively behaved plume sions layer inverse results high between One composed Abstract-Martian 1) London * initial impact 1 effective Arizona also Greeley of Center varied. (i.e., of quality of a kinetic ejecta deposit; To may scaling); © of peak a essentially the Space central impact Observatory, for Impact the determine craters, thin forms Lunar of "regolith" both lunar be for 85281; The central viscosity as terrestrial ice-silicate effects or smaller energy fluid applicable more Viking 1 Meteorite Sciences a 4) *, a the mound 3) of following result and and depression. oscillation of 75 multilobed extrapolation 2 (water) J. as projectile; the Murphys yield mound of and experiments surges or impact Planetary of striking inviscid cratering Mill of debris Fink martian effects target which Orbiter mixtures icy Division, to the Studies entrained the strength sequence layer interpretation Proc. Hill crust) are of surface of 1 flows. potential Center craters collapses Dimensional viscosity 2) , fluids; of crater material Park, Lunar the proportional on discoveries D. Institute of target and excavation such images craters Printed on were 1.0 NASA and water, top these central Multilayer was layer(s) Planet. for E. top the Department ("splosh" London Houston, as in P. energy experiments of ejecta, viscosity viscosity generating appear INTRODUCTION in carried leaving Planetology, observed of of cratering experimental Gault Callisto the melted/vaporized the Ames • H. revealed Set. were viscous analysis martian the mound must Provided United of to mixture NW7 Conj. required 2075 targets Schultz viscous to of out the crater the facies, craters, Texas and Research 2 of and first of be in States have process , a 11th the (in crater. craters in of 2QS, energy the D. surge Geology, yield high less lubricated Murphys, an influence Ganymede. which the and (1980), 77058 by results high to mixture of indicated targets: been Viking target rampart B. or unexpectedly 4 America speed England; than strength the excavate of experimental Center, thus The and rise ice, of energy p. deposits. material Snyder target relatively NASA to Arizona 2075-2097. the 10 to material; the represented oscillating retarded California and the of motion large craters, 10 impacts mission on ejecta impacting Moffett 4 ejecta poise, ejecta /or by the impacts properties Lunar Astrophysics the which Laboratory martian State aerodynamically decelerated 1 pictures initial minor Mariner results , the 2) formation Although etc.) morphology: plume; and into J. which 95247; mound wide and Field, for a is can emplacement and University, projectile, E. balance enhanced transient outer and may and craters Planetary indicates: the most of partly is fluid 3 range 3) California Guest may University the 9 the compatible and impact Data involve planet formation presence images, of differences between experiments: targets) requires a override target "freeze" morphology cavity flow. the Tempe, and thin of System Institute, 1) of 3 satellites energies , fluidiza- ejecta dimen- 94035 impact ejecta, "dry" to These of and muds (i.e., with with pro- of that the the the of as a 1980LPSC...11.2075G 2076 ejecta Johansen, termed ejecta. morphologies, establish atmosphere The terrain variously planets emplacement in high vestigators mine rheological using (Scott, experiments of impact it included logs utilized placement. steel studies (Gault discuss The Facility tions tral min ments, and Impact plications planet formed Our a very pits. © Earth, flat target primary (Roddy diameter that spheres, can geometric Lunar the emplacement satellites and type Several approach chamber 1967); velocities permit to multilohed in impacts Mercury floor is large Not 3.175 their a be termed can for order provide R. NASA 1978; ideally material but Greeley, nearly The properties have and of and controlled, et involving objective only Greeley 2.5 the (Schultz results giving be or by occurrence Mars from they assessment photogeologic x al., Planetary crater and facility geologic to in pressure and m to formation evacuated studied of ranged and "splosh" 10-: .205 suited continuous may Ames a prevent clay craters was 2.0 in 1979). may as the a general 1978), infinite basis may typical of 3 others). et range Moon, m, m diameter; have of relationships and these cratering a our al. consists contained targets and LABORATORY Institute problem have from for deep; fluidized age the somehow 4.77 Vertical the ranged as of as of freezing herein, Gault, photogeologic craters, of of on cratering dimension, lunar to because such experiments functions (Mouginis-Mark, experiments comparison In studies has surface effects and the 5 implications x multilobed impact large martian crater under x • of target addition in 10-: from consideration has experiments Provided processes in mass 10 Ballistic it and 1979) do a be viscous of ejecta-flow (diameter 3 2 one = has target high of of with m, energies m processes controlled been and the responsible not about of material 0.91 mercurian atmospheric martian (Carr s- so the and of and been be for to parameters ejecta was studies speed EXPERIMENTS water by 1 the crater for occur two as chamber Gun two-fold: to clay min applicable to the thin of the considered the 6.35 15 cratering 5.5 floor. from et to versus to because 1979; suggested of crater craters, cylindrical was NASA to craters deposits, photogeologic as contained motion conditions, laboratory have diameter al., Facility, determine on ejecta martian will reduce x viscous x forms for 50 well. 6.9 Ideally, placed 10 10-:i Mutch the pressures. 2.5 such 1977). mb. Astrophysics be ejecta 1) the formation 3 been joules target have on m pictures morphology. and possible laboratory m reported "dry" to impact m or that central flow-like atmosphere deformation These s- and as by the in buckets in in glass, the and results. These types reported the rampart lobe 1 and eliminate attempted the latitude, ; to 0.46 diameter and the volatile-rich water impact studies, 2) effect In atmosphere-free Woronow, 2.2 target craters obtained and discuss target Data pressures peaks terrestrial size, later. aluminum bucket photogeologic impact m suggestive crater (small= these nature experiments x Exploratory and/or craters, deep) The ejecta System previously that projectiles elevation, 10 should on of boundary etc.) by some material. to and Here on 3 the experi- joules. craters forms, so condi- during ejecta of deter- Ames target 2.5 outer 1980; Mars fitted were ana- cen- 0.60 em- and that and the im- the we in- all be of m 1980LPSC...11.2075G J. effects. targets and rials. was were silicon (e.g., buckets with non-layered, periments, and and dry immediately tures was jetting subset, area calculated ious target viscosities viscous posits. placement were tions. a In viscous viscous Analyses surface A three-stage During In this clay angles it yield emplaced measured respect at transient series each Two taken varied: (400 Gault materials © is oil occurs, were Subsequent a section and of mud Such Lunar media was targets. used relatively rotational or strength) of impact, subset, frames the for using observed were types were of and to and the used with before mixed high targets targets. target features cratering in conditions and 75 target batches on target directly there (Figs. we is procedure a varied. various Wedekind, these During measured of successful water. for target Planetary the speed sample s~ the discussed stable speed analyses present with of and 1 viscosity, target (# is for ). (Table material more mud 1,2). 3.0 cratering the such no of 1-8, experiments with After process, after 3.1 viscosity impacts In the motion Silicon measurements the of cannot collected to apparent slurry target Institute EXPERIMENTAL complex to materials the Following was a during 1). as underlying 10 11-14, 1977) a of atmospheric impacts in General each excavation impact general is produce Brookfield The impact ejecta RPM. last the detail events oil pushed pictures repeated. extracted in material be during was to • from shot, motion was every difference first shot viscous 17-27, models are Provided achieved were using allow was in plume Impact laboratory Plastic model held the energy a were mud series used were Appendix ahead the of the the color multilayered lead stage, pressures viscometer were run. terminology completed The pictures 31, nearly used: every each a comparisons involving target targets to angle. by same initial as cratering filmed of disk-type viscosities was between made to and in and and of increase The RESULTS the measured a rheological crater subset, however, a potters fluid the 2 the model constant bucket. divided NASA I. as 33-36) angle general black enabled and to compression of with of rheological in expanding mud, laboratory, in Model target. in 7 because about formation impacts of spindle the the discuss and viscious Astrophysics which 1 a runs, with previous clay high of and Gault for into For the while a model crater and viscosity properties measurement cm impacting yield HBT, slight 15 After each white other apparent mixed speed the subsets whereas of it in three multilayered layer possible tarr:ets mb. behavior ejecta et impact does stage and known and dry strengths homogeneous, and of investigations subset al. the bulge Data in target photographs for motion Clay cratering with parameters of targets ejecta the A not ejecta situ, (viscosity (1968) projectile plume; shot, viscosity apparent in energies dry System the through correla- surface of on /water freeze of of target either which mate- were next both clay 2077 var- ice/ pic- em- and the ex- the de- the for in in 1980LPSC...11.2075G
3 1 t'-.) Table 1. Impact crater experiment data. Pre-impact data: target density (p = kg-m- ), apparent viscosities at various rotation rates [Y/A(RPM) = kg-m- - c:::, 1], (T 1 2); = configuration (R = uniform '-l s calculated plastic viscosities (Y/p) and yield strengths = kg-m- -s- type of slurry fluid (oil O; water= W); target Oo @ slurry; P = powder surface layer; W = water surface layer; S = sand surface layer; N = newspaper surface layer; I = ice surface layer; D = doublet: t""' two shots into same target; T = two clay layers separated by dry powder or newspaper); projectile mass (m = kg), velocity (v = m-s-1), angle of impact = (As = degrees); chamber pressure at time of impact (P = mm Hg). '1= Post impact data: central peak height Chm = m), apex angle (Am) and basal diameter (Dm); ejecta plume angle (Ap) and plume deposit diameter (Op); ::ti surge deposit diameter (Ds); and crater diameter (De). Not all data were obtainable for each run. C) Q.= ""d " - Target properties Impact conditions Crater features --- '<: .....(C= Run p 1)p 1JA T Clay Target m V p hm Dm Am Dp AP Ds De Shot (l) '1 As .... 3 1 1 1 1 1 2 x 10-•kg x 10 3m-s-1 deg. m deg. m m ..... Subset # kg-m- kg-m- s- kg-m- s- RPM kg-m- s- base config. mm Hg m m deg. number e:.. "1 :t...... = Series I ..... =(C A l* 1540 2.26 10.6 10.0 4.74 0 R 4.56 0.55 90 19.0 0. 107 0.178 58 0.44 73 -- 790634 • 2* 1540 2.26 10.6 10.0 4.74 0 R 37.35 1.80 90 19.5 0.425 - 58 - 75 1.34 790635 ""d 3* 1550 2.26 10.4 10.0 4.74 0 R 37.35 1.84 90 18.0 0.383 0.672 64 - 77 1.29 - 790636 '1 p ....0 4 1550 2.26 11.5 10.0 4.74 0 37.40 2.06 90 16.0 0.325 0.463 55 0.71 60 - 790701 Q. (C B 5* 1560 2.77 13.8 10.0 7.72 0 R 4.60 1.15 90 30.0 0. 132 0.229 70 0.46 73 -- 790702 Q. 6* 1560 2.77 14.7 10.0 7.72 0 R 37.23 1.57 90 15.0 0.355 0.621 55 1.45 74 1.25 790703 C" 7 1560 2.77 14.4 10.0 7.72 0 R 37.23 1.71 15 12.0 0.215 0.386 56 1.14 67 790704 ..... 8 1560 2.77 15.5 10.0 7.72 0 R 37.36 1.36 15 20.0 0.241 0.471 52 1.32 68 1.00 790705 =-(C 9 1580 ---- 0 p 37.36 2.09 90 25.0 -- -- 790706 z 10 1580 0 p 161.50 1.49 90 16.0 0.696 0.401 -- 58 0,55 - 790708 >[J). > C I 1* 1580 2.29 72.3 5.0 6.43 0 R 4.56 1.09 90 18.0 0.089 0.216 80 0.57 73 - 0.290 790709 12* 1580 2.29 65.6 5.0 6.43 0 R 37.36 1.87 90 18.0 0.301 0.617 61 1.60 74 0.98 790710 "1.....> '1 13* 1580 2.29 38.4 5.0 6.43 0 R 15.93 1.55 90 10.0 0.190 0.345 59 0.80 74 -- 790711 0 'C 14* 1580 2.29 32.0 5.0 6.43 0 R 10.55 1.72 90 19.0 - 1.50 790713 =- 15 1580 2.29 - 6.43 0 R 29.97 2.06 15 15.0 0. 181 0.305 68 0.50 68 - 790716 "1.... 16 1580 2.29 -- 6.43 0 R 29.04 0.81 15 12.0 0.057 0. 127 99 66 0.170 790719 "1 17 1580 2.14 36.8 10.0 4.60 0 p 37.29 3.78 90 9.0 0.200 0.397 66 0.57 47 -- 790721 0 a D 18* 1640 9.20 44.8 10.0 33.97 0 R 15.88 1.07 90 14.0 0.090 0.228 100 0.51 73 0.360 790722 [J). 19* 1640 9.20 61.6 10.0 33.97 0 R 10.56 1.72 90 16.0 0. 156 0.412 96 70 0.600 790723 "1..... 20 1640 9.20 -- 33.97 0 R 30.00 2.03 15 7.0 0.051 0.156 110 - 67 0.290 790725 (C 21* 1640 9.20 48.0 10.0 33.97 0 R 15.90 5.24 90 4.5 0.248 0.436 79 0.80 67 - 0.560 790726 s 22 1640 9.20 25.6 5.0 33.97 0 R 30.00 4.33 15 6.0 0.026 0.091 130 - 60 - 0.250 790728 23 1640 9.20 96.0 5.0 33.97 0 w 37.27 2. 19 90 4.0 0.278 0.366 58 0.630 70 - 790731 24 1640 9.20 96.0 5.0 33.97 0 w 106.20 1.71 90 19.0 0.379 0.521 48 1.320 75 1.04 - 790732 25 1640 9.20 155.0 5.0 33.97 0 p 37.36 5.35 90 10.0 0.304 0.385 67 43 790733 1980LPSC...11.2075G
E 26* 1720 10.87 160.0 10.0 39.81 0 R 15.82 1.62 90 21.0 - 0.570 71 0.343 790734 27* 1720 10.87 176.0 10.0 39.81 0 R 37.29 1.57 90 19.0 0.050 0.237 131 0.708 76 0.520 790735 @ 28 1720 10.87 39.81 0 R 105.50 1.48 90 22.0 0.160 0.319 81 0.855 77 0.776 790736 t""' 29 1720 10.87 5.0 39.81 0 R 29.90 1.95 15 21.0 - 1.850 66 - 0.315 790737 = 30 -- 0 p 106.30 1.51 90 28.0 -- - 790739 "'1= F 31 1760 122.0 10.0 - 0 R 15.94 1.54 90 20.0 -- -- 790740 =Q. 32 1760 - 0 R 15.91 1.80 90 21.0 - -- 59 - 0.273 790741 "ti 33 1760 275.0 5.0 0 R 37.65 1.79 90 20.0 - - -- 790742 - 34 1760 256.0 5.0 0 R 29.91 2.03 90 20.0 -- -- 790744 l'C = 35 1760 243.0 5.0 - 0 D 37.62 2.11 90 20.0 - - 62 0.456 790745 "'1 15.94 1.62 90 19.0 - -- 0.210 790746 '-< 36 1760 237.0 5.0 - 0 D ..... 37 1760 - - 0 R 12.59 1.47 15 20.0 - - 65 - 0.143 790747 ::t."'= G 38 1800 13.75 256.0 5.0 0.11 w R 4.69 1.01 90 30.0 - - 64 0.266 790749 39 1800 13.75 179.0 5.0 0.11 w R 37.57 0.55 90 30.0 - 68 - 0.473 790750 =l'C 40 1800 13.75 198.0 5.0 0.11 w w 12.52 1.02 90 100.0 - 68 1.23 0.325 790751 • "ti 41 1770 1.93 57.6 5.0 6.92 R 4.67 1.64 90 30.0 - 65 - 0.227 790752 "'1 H w 0 15 32.0 0.018 0.068 - 62 0.271 790754 ...... < 42 1770 - 210.00 w R 15.93 2.22 ....Q. 43 1770 115.0 2.5 210.00 w R 37.59 2.07 90 31.0 0.050 0.275 120 - 63 0.511 790755 l'C -::::, Q. 44 1770 102.0 2.5 210.00 w R 105.49 1.53 90 30.0 0.077 0.382 144 0.726 68 - 790756 !:::,..., C" 45 1770 141.0 2.5 210.00 w R 37.29 2.29 90 26.0 -- 0.717 70 - 0.900 790757 '-< ,..._ -.; I 46 1730 1.56 54.4 5.0 12.42 w T 15.96 0.92 15 26.0 - 68 - 0.224 790758 !::: =-l'C ...... z 47 1730 1.56 57.6 5.0 12.42 w R 4.61 1.61 90 27.0 - 69 - 0.269 790759 ":::--, 48 1730 1.56 70.4 5.0 12.42 w R 15.68 1.85 90 26.0 0.032 0.200 150 70 - 0.466 790760 s· rn> > 49 1730 1.52 60.8 5.0 12.42 w R 37.28 1.92 90 14.0 0.054 0.343 144 69 0.583 790762 50 1730 1.52 80.0 5.0 12.42 w R 4.67 5.49 90 10.0 - 68 0.432 790763 s· > ":'. "' "'1 1800 173.0 w ,..,-. 0 J 51 - 5.0 T 37.28 2.17 90 16.0 -- 0.470 65 0.191 790764 "' "C 1730 80.0 w -.0 :::: '-<=- ? 102.0 :;,, 52 5.0 w T 37.26 2.05 90 12.0 - 69 - 0.469 790765 "'....t") 141.0 .... 1760 !::: "' 1.61 39.2 10.0 22.96 R 3.69 1.03 90 50.0 0.081 0.191 93 0.313 72 - 790766 0 53 1550 w 54 1550 1.61 45.6 10.0 22.96 w R 3.78 2.12 90 40.0 0.120 0.236 85 0.448 75 0.236 790767 "::: a ....:;,, 1620 150.0 5.0 w rn 55 T 37.29 2.17 90 16.0 0.216 0.417 63 0.681 68 - 0.477 790768 '-< 1550 45.6 10.0 w "'l'C s N c:::, '--.I \Q 1980LPSC...11.2075G
"-.) Table 1. (Continued) 0 Oo 0 @ Target properties Impact conditions Crater features t""' = Run p Y/p Y/A r Clay Target m V As p hm Dm Am Dp Ap D. De Shot "'1= Subset # kg-m-3 kg-m-1s-1 kg-m-1s-1 RPM kg-m- 1s-2 base config. x 10-5kg x I03m-s-1 deg. mm Hg m m deg. m deg. m m number ::i;:i Series II =Q. ..,Q "ti 84.0 0 56 1604 10.0 - T 37.63 1.40 90 120.0 - - - 0.762 - - 0.585 791207 - 110.0 w l'C = 0 - - 0.356 (1) "'1 57 1604 - - - - T 4.59 1.56 90 110.0 - - - - 791208 '-< w ..... 58 1614 - - - - w R 4.59 1.50 90 60.0 - - - - - 0.380 791209 -e:.. 59 1614 - - N 4.63 1.60 90 120.0 - - - - - 0.330 791210 ::t."'= w 230.0 10.0 0 60 1614 - - T 37.66 2.06 90 54.0 - - - - 0.380 791211 =l'C - w 1747 310.0 10.0 w • 61 - - T 37.66 2.00 90 90.0 ------0.410 791212 "ti 1611 - w "'1 0 1761 880.0 10.0 w < 62 - T 37.66 2.20 90 120.0 - - - 0.430 - - 0.290 791213 ....Q. 1699 - - w l'C 1761 760.0 10.0 w Q. 63 - - T 37.68 2.18 90 80.0 - - 0.650 - 0.540 791214 C" 1666 - - w '-< 1755 1040.0 w 64 10.0 - T 37.61 2.06 90 40.0 ------0.380 791216 =-l'C 1690 280.0 w 1840 1400.0 w z 65 - 10.0 - T 37.64 2.13 90 80.0 - - 0.470 - 0.305 791217 rn> 1740 445.0 w 1745 480.0 w > 66 10.0 T 37.60 2.07 90 ------0.219 791218 > 2020 1150.0 w "'"'1 67 1720 - 620.0 10.0 - w R 4.43 1.90 90 40.0 - - - - 0.203 791219 0 1770 560.0 "C 68 10.0 w I 37.65 2.20 90 2.00 - - - - - 0. 140 791220 '-<=- 1720 620.0 .... 69 1670 - 570.0 10.0 - I 37.71 2.21 90 6.00 - - 0.380 - - 0.330 791221 "'t") w ,r,, 70 1610 - 225.0 10.0 - w 1 4.72 2.09 90 10.00 - - - 0.210 791222 a0 71 1638 - 220,0 10.0 - w 1 4.45 1.70 90 45.00 - - - - - 0.241 791224 72 1638 240,0 10.0 - w I 4.45 1.80 90 25.00 - - - - - 0.162 791225 rn 6.00 - - 0.318 791226 '-< 73 1638 240.0 10.0 - w I 37.69 2. 18 90 - - 74 1620 280.0 10.0 - R 4.41 2,10 90 10.00 - - 0.430 - - 0.203 791227 "'l'C - w s 75 1610 - 155,0 10.0 - w s 4.56 2.01 90 80.00 - - 0.254 - - 0.203 791228
* denotes shots used in Figs. 5-7. 1980LPSC...11.2075G
angle
inversely
some
quite of expanding
sand
material
clots individual in ranging consisting
and
boundaries
When
immediately; decreasing
rapid over
function some directly Gravitational
greatest oscillate, material.
mounds surge
served
stresses
units in mound actively clay-oil
appearance. strength. percent
smoothed
sured
The
ejecta
Depending
Thus,
Immediately
a
Fig.
negative
viscous
(Fig.
earlier
for
steep
cases,
the
cases
not
that
©
is
the
greatest
in
as ceases
4,
from
Lunar
of
mixtures,
degassed;
less
are
in
with
may
in
which
cohesion.
of
very
proportional
forming
expanding
transient situ
having
in
grains
of 3).
plume
a
out
the
a
this
the
viscosity.
in
is
progressing
central
topographic
less
emplaced
this
than
which various
targets
rebounding
position
The
produce
a
the
collapse
and
upon impact
sufficient
water,
when
before impacts
irregularities
fluid
very
general
quickly
and
after
nearly
then
than
for
bulge
Planetary
sufficient
rapidity
that
initial
a
evidently
fluidizing
cavity
This,
the
perhaps
impact
series
mound
clay,
the
dry
fluid
facies
occur
ejecta
some
decreases
(forming
tears
energy
In and
the
a
of
of
to
there
continuous
ejecta
model
merge
is
more
to
energetic
ejecta
to
surge
sand
form
relatively
central
the
the
target
reaches
targets,
too,
yield
to
preserved
Institute
after
of
surmount
and
shots,
into
(continuous
during the
energy
plume
energy
height,
in
the
most
was
the
small
plume
central
central
fluid
and
plume
for
targets.
to
after
deposit
plume
a
the
appears
magnitude
discrete
strength
more
impact
impact),
strength
with
central
form
target
a
mound
impacts
the
forces
its
and
significant
inversely •
makes floors
the ejecta
decrease targets
and
pieces
fluid
to
crater
oscillation
deposit.
Provided
the
maximum
as
deposits,
mound
mounds
Impact
target
appears
thicker
familiar
The
a
surmount
in
of
post-impact
released
ejecta,
material.
target
to
a
segments
depression),
relatively
of
crater from
targets,
develops,
or
most
of
and
plume lesser
into
remnant
with
for
display
of
rim
effect
be
the
material
some
in
cohesion.
by
generates
cratering
with
The
differences
clay
of
the
the
to
viscous
the
qualitatively
more
viscosity,
lunar-type
target
although discontinuous
the
cases
target.
rim,
ceased. depth,
height,
the
and
volatiles
decaying
be
for
the
the
on
The
extent
impact
when
adjustment
continuous
NASA
target
craters,
post-impact well
slurries,
of
composed target
its
sending
modification
ejecta
water, viscous
lesser
in
depending
crater
viscosity the
recovery in
the
isostatic
targets
effect
The
a
Thus,
and
maximum
and
defined
Oscillation
tensional
viscious
Astrophysics
the
of
surge
the
between
are
from
crater
viscosity
initial
"dry"
heights.
surface
giving
mound
morphology
extent,
the
near
and
fluidity
related to
rim.
a
radial
dissipated
was
central
clay,
ejecta,
at
the
sheet
being
blanket
of
the
after
of
adjustment
large
of
fluidized
surge
continuous
targets
also
rim
laboratory
is
crater
the
discrete
Oscillation stresses
material
ejects
them
plume
two-fold:
stage
height
impacts
the clay-water
appears
may
and
Each lowest
extent
and of with
Data
(Fig.
of
to
impact
was
greater on
bright
impact
"plates" mound
deposit
of
the
floor
the
viscosity,
and
the
rim.
finally
a
"freeze"
is
strength.
System
(Fig.
the
deposits
angle
material
of
not
material
varying
2).
parcels
flooded
exceed
central
of shown
that
in
begins
in
scales rays).
target
target
to
(mea-
outer
shear these
in
is
2081
zone
later
with
The
The
may
pre-
was
this
dry
and
is
dry
2). be
so
or
74
to
is
in
a 1980LPSC...11.2075G
2082
©
Lunar
R.
Greeley
and
L~M%'.!'i_!:~t'{_u0;},-'~'.~
Planetary
et
al.
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\
\
CENTRAL
CENTRAL
CENTRAL
•
Provided
COLLAPSE
DEPRESSION
MOUND
MOUND
by
the
#2
-BULGE
NASA
/
I
I
EJECTA
Astrophysics
DETACHED
PLUME
Data
System
1980LPSC...11.2075G
following following
different different
pacts pacts
total total
were were
depend depend
targets targets and and
and and
reflected reflected
mound mound it it
determine determine
either either
diameter, diameter,
In In
strength. strength.
in in
both both
cases, cases, metric metric
to to effects effects
of of to to
a a
shots shots
floor floor
Fig. Fig.
of of
which which
speed speed
of of the the
sends sends
deposits. deposits.
sends sends
3) 3)
is is
later later
The The
ejecta ejecta
target target
Impact Impact
Impact Impact
discrete discrete
asymmetric asymmetric
order order
the the
viscosity viscosity
high high
ejecta ejecta
1. 1.
possible possible
produces produces
rock rock
© ©
central central
of of
a a
normal normal
motion motion
successive successive
in in
into into
sought sought
in in
Sequence Sequence
the the
surge surge
Lunar Lunar
oscillation oscillation
oscillating oscillating
target target
paper.) paper.)
(perhaps (perhaps
such such
material material
in in
plume plume
we we
75 75
some some
on on
energy energy
(Numbers (Numbers
to to
which which
plume plume
waves waves
segments segments
recording recording
(Gault, (Gault,
We We
experiments experiments
ejecta ejecta
for for
at at
discussion discussion
the the
homogeneous homogeneous
qualitative qualitative
shots, shots,
provide provide
impact impact
of of
pictures pictures
recently recently
3.2 3.2
a a
and and
was was
cases cases
pits, pits,
as as
to to
angles angles
and and
forms forms
bucket, bucket,
central central
material material
example, example,
in in
experiments, experiments,
point point
across across
of of
lobes lobes
deposits; deposits;
ejecta ejecta
produce produce
the the
shots shots
water water
Planetary Planetary
from from
Dimensional Dimensional
pattern pattern
dimensionless dimensionless
because because
refer refer
impact impact
high high
oblique oblique
deposited deposited
of of
central central
14 14
"freezes" "freezes"
1973; 1973;
all all
a a
(compare (compare
energy, energy,
a a
mound; mound;
size size
deposit deposit
of of
techniques techniques
the the
as as
the the
out, out,
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ran ran
basis basis
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flow flow
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relationships, relationships,
as as
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and and
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and and
4) 4)
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sequence, sequence,
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Gault Gault
multiple multiple
of of
or or
a a
Institute Institute
functions functions
clay-oil clay-oil
consider consider
mounds mounds
however, however,
central central
impact impact
walls walls
of of
as as
ejecta ejecta
over over
on on
for for
approximately approximately
to to
deposits. deposits.
to to
sufficient sufficient
gravitational gravitational
the the
the the
series series
water water
subsequent subsequent
as as
detached detached
clearly clearly
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leave leave
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Fig. Fig.
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scaling scaling
with with
analyses analyses
ejecta ejecta
the the
and and
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15° 15°
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and and
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2): 2):
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inhomogenieties inhomogenieties
above above
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1) 1)
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we we
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floor floor
showed showed
expands expands
conditions conditions
the the
experiments experiments
morphology. morphology.
to to
rim rim
formation formation
was was
of of
Impact Impact
oscillates oscillates
may may
impact impact
Because Because
results results
gravitational gravitational
different different
varied varied
and and
oscillations oscillations
full full
those those
be be
targets targets
acceleration, acceleration,
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and and
high high
after after
the the
begins begins
crater crater
to to
lobes; lobes;
of of
No No
power power
pit; pit;
with with
the the
less less
produced produced
by by
well well
form form
outward, outward,
size size
the target target the
functional functional
collapsing collapsing
influence influence
Wedekind, Wedekind,
late-stage late-stage
cratering cratering
multilayer multilayer
energy energy
the the
surface surface
rim rim
of of
experiments experiments
will will
to to
the the
many many
derived derived
energies energies
1977) 1977)
to to
5,6) 5,6)
the the
deposits, deposits,
than than
to to
our our
be be
terraced, terraced,
impacts, impacts,
ejecta ejecta
of of
tear tear
form form
subsets subsets
NASA NASA
to to
collapse collapse
ranging ranging
oscillating oscillating
be be
In In
generation generation
be be
influenced influenced
½ ½
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a a form
pushing pushing
may may
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into into
1 1
early early
show show
parameters parameters
if if
from from
rounds. rounds.
some some
ejecta ejecta
a a
power power
/20 /20
directly directly
plume; plume;
presented presented
in in
and and
had had
bucket. bucket.
of of
Astrophysics Astrophysics
the the
impact impact
central central
the the
central central
relationships relationships
discrete discrete
and and
1978), 1978),
superposed superposed
targets targets
viscious viscious
central central
have have
of of
deposit deposit
parametric parametric
of of
of of
the the
analysis analysis
a a
target target
that that
from from
experiments experiments
plume plume
no no
target) target)
central central
ratio ratio central central
experiments experiments
involving involving
small small
2) 2)
the the
experiments. experiments.
of of
target target
bucket bucket
depression, depression,
by by
To To
comparable. comparable.
rebound rebound
of of
apparent apparent
been been
energy energy
dry dry
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energy energy overlying overlying
are are
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"bulge" "bulge"
bucket bucket
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targets targets
of of
very very
in in
boundary boundary
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strength. strength.
determine determine
the the
mound mound
mound mound
ejecta ejecta
Data Data
which which
sand sand
impact impact
more more
high high
viscosity viscosity
influenced influenced
included. included.
relationships relationships
used used
walls. walls.
of of
first first
vertical vertical
for for
low low
dimensions dimensions
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for for
System System
flat flat
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diameter, diameter,
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involving involving
aimed aimed
detail detail
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Of Of
energy energy
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Crater Crater
floors, floors,
In In
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In In
soils, soils,
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2083 2083
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on on
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all all
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2086
©
Lunar
Fig.
ejecta "lunar"
volved
R.
and
4.
boundary.
Greeley
impact
(a)
Comparison
(b)
type
Planetary
deposits
into
et
(a)
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Institute
al.
of
involved
with
ejecta
mixture.
that
•
impact
morphology
Provided
of
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of
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pyrex
by
for
the
in
sphere
"dry"
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NASA
into
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Astrophysics
dry
target
(b)
pumice
showing
(a)
Data
showing
powder,
well
System
defined
ragged
(b)
in- 1980LPSC...11.2075G for (pg). the proportional density power pghm, observed creases implies that "gravity stronger (Gault, fluences and density. the target yield larger ph~. tion energy compares 1978). mound peak 0.25) 1500, pg, Mound 1. A A In In the ½ central Eh viscous crater is second third our The Figs. Gravity height strength, and than © for power than viscosity, run height dependence term transient that or in 1973). height Lunar and of influence experiments scaling" hm group the experimentally the dimensionless central dimensions decreases 5-7 the yield #790735 the mound. should effects for scaling pE/rJ = to and of effects effects same and should hm T. fourth 0.2 we exhibits gravity the the pg strength-dominated or strength crater For k = ~ Planetary 2 peak applies, on (Table have • scale should m strength 4 energy and conditions 0.7 energy In factor Power suggests (Figs. should in of scale we implies crater a root scale stress, any height. ( typical gravity gravitational only plotted diameter n pg} sought as group and 1), E, for In.stitute are large be scaling as includes divided \ 5-7), law such and a as thus morphology so would 0.28 a that greater viscosity the comparable. impacts that due constants, the experiment This that where slightly central , and curves relates to the increases r cases predominate where ¼ by the inverse (correlation • expected determine to by when rJ dominate. impact the power Provided prediction impacts, inverse 2 Impact acceleration power impacts the Ip fourth g strength. by into peak of where energy greater influence h~ = the than high were viscosity of the comparing in Now (all 10, = of energy targets of calculated cratering if by height of power the the impact O50 the crater form into energy, We in strength target coefficient) gravity we units the the was to then dependence target This square considering our conditions impact i~(~.0 of NASA all viscosity, can find impact on water vs. of h experimentally of effects m-k-s), dimensions fitted target energy, in experiments viscosity functional a lead = mound gravity, the weight. alone determine pghm different viscous viscous 4 or viscious solid of Astrophysics ) k(E*t, energy. (Gault energy, viscosity. peak to viscous = to strength, 6 under T operate, YJ on gravitational 0.82. were = ~E decreases relatively basalt = the height: = hm and Thus, target stress, targets 3000 T. stress height energy relationship energy where 10, should The and , the data. Thus, so closer which modifying effects and low corroborated Data Y/ This and 7 that >> strength relative one where Wedekind, ! they was Y/ = should m 1 E* indicates height small 2 (0.28 terms in Figure System scale strength I T gravity, , 20, to phi;i, second granite central excep- stress, apply, which target = is much have 2087 ½ was p this YJ the the vs. in- in- be E/ or as or to of = 2 5 I 1980LPSC...11.2075G 2088 crater here. correlation The strength with Figure Figure © the higher Fig. (see density (T) Fig. Lunar morphology, and exerts 5. theoretically 6. text). 6 7 R. shows Plot Plot of shows energy (p) and exponent Greeley c3" O .c: ...J r 6 .c ...J O and E 0 of of E 0 = a Planetary -2~----'------~----~---~ -1 o~----~-----,------.------, maximum -2L------L------4 maximum (E); -1 significant 0.95 the energy central 0 and correlation et effect predicted is value al. (E); Institute better this central central mound hm correlation of influence -3 and difference = the yield coefficient than mound mound ½ 0.8(Efr) • height the Provided root that LOG 1 coefficient height 0 on better height LOG = strength scaling 10 scaled for 0 -2 is the 0.94. · 32 E/pg by (hm) , (hm) probably the 10 r correlation cratering the = = E/T as 0 against for gravity as 0.82. and NASA 0.94. a a function mound function indicates Open -1 2 not Astrophysics process. energy scaling both of circle statistically height: of target gravity a and suggest = in closer shot yield Fig. 0 3 Data viscosity. (g), #790735 strength 5, correlation System significant target that although yield The 1980LPSC...11.2075G
than
the
Thus
fluid
compute
typical
The section) value
mound so (Table
we
conditions impact bulk about "ejecta of viscosity
plastic
the
that
power
could
©
general
to
energy Fig.
than
density
it
for
Lunar
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10
1)
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martian
height
craters Yuty
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appears
flow"
4
gravitational
7.
gravitational
central
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expect
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poises for poises
4.0
as
law
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Plot
under
1.0
and
10
objective
a
might
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and
was
craters
exponents,
DISCUSSION
of
9
for
formed
viscous
multilobed
Planetary
that
martian
martian
(see
kg-m- .c.
0 C,
_J
maximum
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E
soil,
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-1
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~----~-----~------'
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pgh
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Institute
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surface
hm
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n,
the
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scaling:
or
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=
LOG
In
experiments
a 6 a
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experiments
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the
effects
AND
(.04)
et
10
mound
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YJ
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0
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10
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greatly
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PLANETARY pE/71
high
California.
Impact
pE)
to
height
nonexistent.
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runs
1977)
to
km
2
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predominate
Substitution
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10
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to
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The
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,
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oscillating target
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NASA
Thus
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at
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3
0.95.
viscous
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=
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determine
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least
IMPLICATIONS
behaved
Yuty
and
yields
in
3.8
(1970,
over
viscous
Astrophysics
if
=
Based
infer
of
described
viscious
to
0.95.
the
central
an
m-s-
1500
terrestrial
crater,
of
forces
½ mound.
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a
apparent
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on
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513)
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Data
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Assuming
as ones.
order
calculate
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experiments
calculated
3
can
Choosing
viscosity
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System
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diameter
apparent
behavior
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inviscid
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form
2089
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of
a
a 1980LPSC...11.2075G 2090 the mensionless less, understanding of and volved multilobed ejecta attempt types ments. around lobed Mark 3) can comparable on are lobes. mercurian craters. mercurian Until highest regolith ment. features the mixing rays same around and around and descrete units ejecta are impact single et The Bright martian Detached The isolated, craters al., laboratory overlain flow-type occur emplaced © Roddy, thickness Gault, could the are (Fig. such area, craters and Lunar We deposits plume, coherent primary main of and, all certain they 1976). many velocities), or to rather experiments clots fully ray local in suggest R. of multilobed surface Head, craters: be craters a derive 2). suggesting detached and 1979). 1978). parameters, to ejecta multiple by ejecta could equal classification through Greeley patterns and and deposits. a can classified, of martian ballistically In (Gault models. characteristic At martian consist than impact materials. Planetary function ejecta large a the 1979; 2) that be to layer the a and Although "dry" Photogeologic size Nevertheless, deposit 1) coalesce deposits followed remnants post-ejecta single gained et suggest tiers). flow crater bright mass and the experiments provide flow scale that the multilobed of (Fig. of cratering al. and craters. Thus, Extrapolation during and Institute individual not few several upper The the isolation Greeley, is bright on lobes; (Fig. changes lobes model located but Radial of (Carr of others) only isolated ray 8) rare of and developed, of by the effects the the of the the qualitative initial martian multilobed are which disperse plume • layer. excavation 1) patterns; an rays on on facies, implications produce of or and studies dependent Provided presence craters. surface. processes initial et of striations can models the on similar and 1978), stage and eroded in other Mars, the from ejecta al., of formation. 4) to are can apparently deposits. target be ejecta craters, high target we not therefore flow study into planetary moon, 1977; show of derived formed insight 2) by the ejecta the craters may be which These where Once to and would continuous of prefer preservation involved can all the deposits velocity on properties satisfied a lobes those main of plume detached deeper, viscosity Mouginis-Mark, be that of of system NASA degree such The and occur the deposits. our Rather, on impact into patches similar rays by from is required which be it individual to scales part of there the observed the initial degree ejection may consist experiments for phase in clots thrown Astrophysics discuss from simultaneously. the do continuous on two of viscous ejecta of flow-like the ejecta influence of on surface, geologic the are fluid (age), once occur, is some development requires not appear smaller general Rays ejecta to the may secondary formation sources: of morphology more of necessarily surface of farthest explain of parameters, elements blanket ejecta be around targets ejecta clumps dispersion, the material but or 1979, an not both may they ejecta. Data plume appropriate however, to material than their for clots all ejecta processes a upper the morphologic remain excavation, 1) be as host each of System field be commonly (ejected of ejecta Mouginis- those (Arvidson lunar cratering; Nonethe- tears the one observed of presence develop- of separate (Schultz deposits Martian the primary martian to present present (Boyce (which "dry" multi- of bright class. in occur initial some upon form type flow they as ele- into and and the di- in- to at a 1980LPSC...11.2075G form crater; including material mass may water, seismically on dition, ments, subsequent mass trajectory presence near Mars behave the a Fig. deeper which preted consists wasting. © lubricating possible the all ~-il}~ melt-water .~::- Lunar is rim. 8. causing of -:.,_'""t.. dispersed oflow •. three overrides ejecta Martian to excavation being active " an deposition similarly .~;. !,· / result o Given of l and ·> The _,{_:iltl~t' atmosphere ):: early conditions fragmental viscosity deposition plume deposited, .-'..- Planetary multilobed layer (Schultz from part third (Carr .? water penetrates these to :: arrival of , initial closer ¾ of landslides angle factor, the et plume material Institute conditions, droplets crater and which favor debris, bright closer ejecta and al., of volatile varies to oversteepening, certain Gault, (-8 material 3) ray 1977)], the mass being may assuming • to (Schultz possibly and the rich km inversely material. Provided Impact crater, the we , 1975) cause ejecta derived in wasting material mass vapor 2) diameter) crater ,_ would assume ,, the the and containing (VO cratering from by and deceleration fractions is from with .. that (Schultz the following conditions: results processes oversteepened rim region '-·• be Gault, IOA showing 3) the an that is NASA the al than 21,22,23). emplaced as as . upper a in impact ,t' viscosity; from: ejecta in entrained high around 1979) suggested ': viscious and Astrophysics bright 't-, in layered of "dry" >':, (Sharpe, the angle Gault, the < 1) that as plume ray a ~-:-- the on the lunar targets regolith fluidized the ejecta the ''\' finer thus pattern volatiles with ~-~\,;: lithologies ·),/·,:.- would by the higher crater Data 1938). 1979) deposits :j:~~;~ 1) case, the .. size the deposition rim layer; inter- the mass :""-, :: System enhance ballistic gravity experi- [gases, and ejecta, is plume In of ejecta 2) 209 may still can the ad- the its J 1980LPSC...11.2075G 209 flow istics posits be could Although extend extent deposit mound; highly (even curred. versus performed. suggesting Carey, martian The An 2 treated conceivably culated Fig. 7.1 at a certainties subsurface km "normal" previously oscillating taking occur © to hemispherical second crater fluidized would left beyond 1980) resulting Lunar km3, multilobed diameter the 9. be this is R. essentially Two that volume However, 4.8 emplaced in and into size Greeley areas and have excavation deposit inherent and be flow source the km martian an flow crater the central substratum. account from described any of less. Planetary in ejecta bowl of of same been craters diameter continuous the material crater of et in at time would for craters as early its shape) first It to determining volumes volume right al. mound, subsurface rebounding mass made, landslides, account the is the collapse bowl, Institute in exceed by order (Carr during has in conceivable, for of be transient the main Although 0.2 of to the 28.9 which a even superposed a plume similar for 38 (Mutch minimum km produce history uplift vertical estimates rigorous et km:i_ km:3, sequence, vary by • excess mass material deep, taking Provided thus estimated central al., several crater of ejecta Thus, deposits to inversely lengths some the and giving of of volume. volume 1977). into accounting however, that overlapping analysis on ejecta central the some volume (Fig. volume during Woronow, by mound ejecta the , account times a observed from the f estimates the maximum crater, of «, We Although if mechanism S, unstable with mound. 9) ,*: I ejecta could is volumes NASA .4 shadow it interpret the of the that ," estimated "bulking" of and and km:i, were for -~..., the flow the and ejecta volume 1980; crater excavation in Astrophysics be plume "bulking" ,..., the of the a the measurements. exceed deposits is the viscosity we excess volumes maximum derived more the lobes. ; required ejecta to , surge volume flow-like extent Mouginis-Mark of .. volume experiments, v~+ envision be deposit, of collapsing ejecta maximum to 38.8 than the result could blanket other deposit volume (assuming of from stage Data has of of km and crater the one for Crater character- the 3 the these from its than ; not System cal- un- r~-- 3.8 fail .. a ejecta), has ~.;-,-.-": : of several -~ '-"'~• central failure target. .., ,"'J'>., lateral -f~ could deep, could surge areas ,,...,.... bowl been ... and ;°,,.,:_~\ and '~',:· de- ',, • oc- i~"", ~: . • ('t, ., .,..J ,, 1980LPSC...11.2075G competent crater account in iments bucket, flow certain that both ejecta lobes masses. (1980) propagated show veloped more The Although the © a of the 635A82). flow Fig. secondary of interior materials typical extensive experiments Lunar rim emplacement. model and emplacement were multi-ringed debris martian for in However, multiple 10. inner lobes was rock Singer some upward the A a terraces and probably of involving having planet-wide 35 craters; (although comparable rarely formation stratum lobes Planetary lunar km-diameter craters wall respects ejecta and striations less vigorous and through basins mechanisms martian slumping preserved. due and and Schultz volatiles an slumping an may underlying flow Institute outer analysis to mercurian of crater oscillating outer this to (Murray, craters overlying waves oscillations be on the lobes, than mass scarp (1980), of and southeast shear could certain ejecta • multiple Although for lobes. the those of has Provided unconsolidated of reflected wasting. interior this and the wall 1980). impact central lines ejecta they Impact be not lobes, in of type This main involved which in tend Amazonis tiers analogous been by similar is may some large appear terraces, from craters Striations present), cratering peak the or continuity ejecta lobes multilobed to of carried competent reflect as NASA of display ejecta the to very Planitia to volatile-rich has suggested the appear (Fig. lack mass those to and walls tend in Astrophysics been scour out, craters fluid observed oscillations reflected lobes. well viscious may showing may blocks, secondary 10). described that and to to some developed targets proposed reflect form. marks by cross have We reflect We occur material. floor well-developed and targets Mouginis-Mark on martian nry from energy Data (VO interpret impact point lunar-type in continuously less by in here of crater some multiple in shear Frame the System to which late-stage the landslide into well We out involve explain craters exper- ejecta target fields these lines note 2093 that the de- a 1980LPSC...11.2075G The tatively a Acknowledgments-Many experimental conditions. craters ice-silicate partly crusts. currently lava. to multiple erties ready scribed experiments. target motion under periments. 2 paper Boyce Arvidson geological of observed craters terraces pheric multilobed such 094 bearing ameter-frequency and 162-165. Icarus The simulate local © impact willingness of constitutes buckets; Contract The Salomone as J. Lunar pictures; Lunar through here. and the density. 27, M. R. to suggest target rings loss and Finally, NASA conducting experiments on in R. various E., unit, 503-516. This and bodies We have Such their multilayered crater. and and experiments R. the No. have problems or results G and V. Coradini to M. the thank Roddy dimensional degassing work ree/ey Leach Planetary TM-79729. Planetary we accomodate it Conversely, gain Sisson, experiments. NSR mechanisms distributions associated problems, formed (1976) mixtures; Lunar impacts suggests such shallow, thank Where first was lies D. and of 09-051-001 people impacts et M., almost Latitudinal of and Planetary J. supported as the al. Institute all subsurface M. ice/silicate in Institute Carusi from in in (1978) T. large our into such Ganymede who Planetary flat staff that scaling contributed Plummer analysis. (abstract). however, features. Timmcke viscous more 5.0 the needs; into certainly of with floors got the "magma A., of Martian is Geology impact craters the variation by REFERENCES • formation walls CONCLUSIONS operated the their the Caradini targets Provided impact time, competent NASA C. Institute assisted target volatiles, mixtures, targets assisted Reports NASA-Ames that We Furthermore, Wilbur National to occur and hands rampart craters Summer have of exist the of oceans" size grants are by appear A., properties including and wind many with Callisto. Contribution by successful and in in for in of the produced implications continuing Aeronautics near and Fulchignoni craters: the with the some all and Planetary materials the Intern, NSG-7429, its (i.e., erosion P. 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B. B. In In 1980LPSC...11.2075G some as elastic portional an or depending less target measure An which we because stants, permanent bodies of experiments. concentrations drill the power shaw, for after and addition, cause accompanying decreases clay laboratory is to time to rheologic promotes Newtonian shot. strength strongly rest, surface periods 2096 impossible a These Four be a In viscosity more During Very internal can every underlying slurries solid several than with higher particles. of impact, © its power replaced. general, However, which the could 1971). solid of with Ty layer characterize Lunar stirring, groups high hn the when fluid they that of nonlinear strength a RHEOLOGY to the to a relationships large properties. and batch degassing actual our both primarily conditions. deformation stirring structure viscosity critical a viscosity we produce either of or with applied (E can cause shear might raising concentration of R. commonly (oil Bingham Within At to experiments 1/p• Time clay assumption increased a the and = the used. of Homogenization amounts rheologic sand of our monitor perhaps linearly Greeley behave viscosity concentration. volume or la-1°; and clay water This required clay attachment. behavior, slurry stresses value particles both be Planetary slurries on stress water) the the rheologic dependent which and its and this The which or After E expected viscosity Measurements between body's suspensions the occurs. plastic is rheology steep clay bulk = the or exhibit both viscous duration an continuously of strength because called range, concentrations used parameters. temperature not concentration to of and strain et we to often energetic silicon (Moore, are experimental varies OF associated exhibit air viscosity begin was viscosity in our be al. flow as the resistance Institute measurements frequently being The in viscosity the generated effects Bingham are the which rheologic Bingham in At the may of different fluid, a rate; EXPERIMENTAL added, leads experiments by the containers of after interparticle to oil. lobe linearly fluid the proportionality the were about consistencies a yield inadvertantly viscosities 1965). shearing the worked. inferfere shots, runs. rise and continuous This made The a- all of of preparation depending are the yield fronts. slurry impact. to to • mixing has of Bingham = to made materials the the of procedures behavior. strength, altered of locally Appendix from properties 30 stiffening yield by produce Provided sometimes with strain suspensions At suspended stress), effect flow. Here much during less the strength. and slurry. the percent slurries indicated stress. was an Depressurization was Without high with forces by would that the in strength effects, same at the Clay than restirring. rate amount of we upon is range combining clay then model. mixed some constant of are that Ty. the concentrations the our one the concentration the Similarly, of recorded partly by and concentration ranged could list solids our This are observed, is particles not thus about suspensions For that sign specifying dimensions was whether observed the accomplished the site were experiments slurries another, the of of and proportional to some other into target dependent reduced. A be TARGET the reversed yield clay. formation stress lead characterized flow of of decrease these expelled many is NASA over Bingham rheologic one mixed 2 greatly either targets the impact, the n stiffer of and factors percent were the materials. to of depending caused value properties In flow leading of the power about greater clay the (Moore, plastic some slurry inadvertant as were of their Astrophysics the As applied at those two immediately by were from in varied component composition influenced upon with of to by changes the patterns Newtonian material the where increases suspensions measurements were the chamber exsolution proportion 8°C by solids, MATERIALS commercially degree law multilobe clay the selected stirring to viscosity, during by than slurries, experiments test the much icy changes the 1965). on mixed shear from an by during applied these effects determined nonlinear suspensions surface target the facility in around Ty, exponential rheologic adding deforms time of clay (van roughly less at inevitably stirring before viscosity before Data viscous stress as At of interaction viscosity clay strain mineralogy craters two thus of to the very begin r,p; in were such target bucket stress slurries of increasing well Olphen, the must the layers using more obstacles available yield material is course System effects where below changing standing. is either impact high or rate as under changes. which a to allowed minimal gas amount to may controlled requires greater and materials material, raised occurred variation be after the and dry a strength and develop also plastic, have (Grim- is speeds during power Ty, of a of 1977). might as taken show third yield ideal con- pro- clay clay clay also also is stiff and had the the the the led no an or In of to to in It a a a 1980LPSC...11.2075G to spindle equated area and apparent absolute of described Rheologic through non-Newtonian of functional induced type the rheologic rate yield was readings properties computing instrument sured some earlier. Table Helipath that ments, valid by set, such shot; viscosities run both In Rounds flow these We Although experiments In our some computations (no yield complete varies we constructed. spindles was slurries as strength only subsequent crater of directly attempted I that ongoing then Apparent in misfires) © central can calibration geometries lists movement. with 56-75 these viscosity as indicate attachment viscosity conditions strength measured by Lunar at of the relationships data and the widely viscosity allows yet better this morphology the the the were the the which Hulme determinations and by fluid difficulties. effective (series yield peaks experiments fluids. unknown (runs were was procedure shaft. experimental target to relatil'e measured were and viscosities experiments, using These the intercomparisons plastic across must for determined. scale is with allows and The calculate could and specific data strengths (1974). assigned which the collected and 1-55) Planetary "instrument 2) At Newtonian only Despite materials the be indicated a areas measures our spindles plots stress were ratio the was viscosity collected a constant. viscosities known surge not As simple determined cone stated rate indicated made allows and at to results we First radius were the a an be measured of conformed conducted data. of were a each including these using number. was of waves are single thus indentation Institute for consist the alternative Rheologic mass used for computations total Bingham by shear fluids the the rotation made could for measurement viscosity" At to with of attempting run. calculated computed Impact the should t-bar batch these Bingham-like limitations, Experimental a represent instrument martian for torque every by the and RPM this was shear rate, Brookfield first and other after of Runs for be Second, those in indirect to the cup spindles, • the samples data properties stage of a observed measured conditions each December produce to method those value target series Provided the however, stress cylinder more necessary the impact, similar 1-55 (Shaw conditions. force holding measurements for by the currently of to Impact average will we apparent in we shot. surface readings shaft, the methods. determine were dividing average expected properties, calculated Model material. of collected (series to viscous highly but of also are were (Moore, in fluids. internally with et viscosity of experiments. directly shear and it the gravity. by In and high 1979. measured data and if cratering investigating to al., values provides the underway, apply areas multilayer able the the test viscosity 1) either HBT viscous were the batches overcome the target target For a for speed rate every clay Relative the were 1968) In 1965). plastic NASA same plot from it fluid, geometry to (van could Then, to force consistent which Bingham a converted has the absolute Synchrolectric a and characterize slurries a for materials. carried properties absolute Bingham disk of motion fluids. 2 which in of measure the spindle Wazer We for first we three and configurations to only viscosity each Astrophysics shear these yield for is by the target viscious might 8 or plots. non-Newtonian do are not shots the of this set the materials, out values The by viscous can t-bar be inherent target. pictures. results. to strengths et not functional measurements, strain is material, the attempting a Third, of materials, of calculated disk-type were following measured not in al., area. absolute used material the during viscometer values, be the yet at experiments, June targets transient Viscometer of adequately During 1963). rate the relative converted resistence fluid's set have Presumably, the problems. the Data for plastic the Strain Each are and the and base. relationships. versus prior we spindles, properties force constant as actual all for a to variables values The fluids. being a July, the System first procedure resistance successful structures described values are rheologic eliminate means measure- rotates viscosity rate the differing Neither to second with torque values to reflect plastic to stress series strain First, 2097 using disk- 1979. were mea- each The was the the the the for so of of of a a