Imperial College London

Professor Gareth Collins

Faculty of EngineeringDepartment of Earth Science & Engineering

Professor of Planetary Science



+44 (0)20 7594 1518g.collins Website




4.83Royal School of MinesSouth Kensington Campus






BibTex format

author = {Watters, WA and Hundal, CB and Radford, A and Collins, GS and Tornabene, LL},
doi = {10.1002/2017JE005295},
journal = {Journal of Geophysical Research: Planets},
pages = {1773--1800},
title = {Dependence of secondary crater characteristics on downrange distance: high-resolution morphometry and simulations},
url = {},
volume = {122},
year = {2017}

RIS format (EndNote, RefMan)

AB - On average, secondary impact craters are expected to deepen and become more symmetric as impact velocity (vi) increases with downrange distance (L). We have used high-resolution topography (1–2 m/pixel) to characterize the morphometry of secondary craters as a function of L for several well-preserved primary craters on Mars. The secondaries in this study (N = 2644) span a range of diameters (25 m ≤D≤400 m) and estimated impact velocities (0.4 km/s ≤vi≤2 km/s). The range of diameter-normalized rim-to-floor depth (d/D) broadens and reaches a ceiling of d/D≈0.22 at L≈280 km (vi= 1–1.2 km/s), whereas average rim height shows little dependence on vi for the largest craters (h/D≈0.02, D > 60 m). Populations of secondaries that express the following morphometric asymmetries are confined to regions of differing radial extent: planform elongations (L< 110–160 km), taller downrange rims (L < 280 km), and cavities that are deeper uprange (L< 450–500 km). Populations of secondaries with lopsided ejecta were found to extend to at least L ∼ 700 km. Impact hydrocode simulations with iSALE-2D for strong, intact projectile and target materials predict a ceiling for d/D versus L whose trend is consistent with our measurements. This study illuminates the morphometric transition from subsonic to hypervelocity cratering and describes the initial state of secondary crater populations. This has applications to understanding the chronology of planetary surfaces and the long-term evolution of small crater populations.
AU - Watters,WA
AU - Hundal,CB
AU - Radford,A
AU - Collins,GS
AU - Tornabene,LL
DO - 10.1002/2017JE005295
EP - 1800
PY - 2017///
SN - 2169-9097
SP - 1773
TI - Dependence of secondary crater characteristics on downrange distance: high-resolution morphometry and simulations
T2 - Journal of Geophysical Research: Planets
UR -
UR -
VL - 122
ER -