Exploring Subsurface Structures of Pit Craters Through Seismic Reflection
Discover the technique of seismic reflection imaging to unveil the subsurface structures of pit craters on Earth and Mars. Follow the analysis of seismic data to map pit craters and their connections to geological features like dykes and fault jogs, shedding light on the formation processes of these intriguing landforms.
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Imaging the subsurface structure of pit craters Modified from ESA/DLR/FU Berlin (G Neukum), CC BY-SA 3.0 IGO; Magee & Jackson, 2020 Dr Craig Magee, Prof. Chris Jackson, Dr Corbin Kling Dr Paul Byrne E-mail: c.magee@leeds.ac.uk @DrCraigMagee
What on Earth is seismic reflection? Seismic reflection data images Earths subsurface in 3D Energy reflected from boundaries between physically different rocks Measure arrival time and amount of seismic energy reflected Stack data to build a 3D view https://www.youtube.com/watch?v=FN8IAb0rG9A
What on Earth is seismic reflection? Seismic reflection data images Earths subsurface in 3D Energy reflected from boundaries between physically different rocks Exploration ship Receivers Source Measure arrival time and amount of seismic energy reflected Reflections Stack data to build a 3D view Galuzzi et al. 2017 Jackson et al. 2013
What on Mars is seismic reflection? Seismic reflection cannot image subsurface of Mars in 3D (yet!?) Mars Can typically only study planetary surfaces Cracks, bumps, holes, and other stuff hints at planetary processes https://www.usgs.gov/media/images/mars-geology To interpret these we compare to similar structures on Earth Here we ll focus on dykes and their associated structures dlr.de/content/en/arti cles/news/2020/02/2 0200514_uparching- stress-and-strain-on- mars-north-of- labeatis-fossae.html
Pit craters How do pit craters form? ESA/DLR/FU Berlin (G Neukum), CC BY-SA 3.0 IGO Magee et al. 2019 Pit crater subsurface structure largely unknown
Pit craters in seismic reflection data Magee et al. in prep Study area offshore NW Australia in sedimentary basin We map 61 pit craters and show some link direct to dykes, others to fault jogs
Pit craters in seismic reflection data Magee et al. in prep Most pit craters distributed along dykes Variance attribute highlights change in seismic trace
Pit crater plan-view morphology Magee et al. in prep Pit crater area decreases with depth Pit crater long axes randomly oriented
Pit craters in 3D Can we use pit surface expression to infer subsurface structure? Hypothesis 1: pit crater size at surface reflects pipe height pipe height a proxy for regolith depth lot of scatter and only poor to reasonable correlation Extract various geometric parameters Define deflection and funnel height Magee et al. in prep
Pit craters in 3D Can we use pit surface expression to infer subsurface structure? Hypothesis 2: pit crater length correlates to crater depth + volume assumes pits not infilled yes, but different driving processes not distinguished Magee et al. in prep
Implications for space (planetary) exploration? Modified from ESA/DLR/FU Berlin (G Neukum), CC BY-SA 3.0 IGO; Magee & Jackson, 2020 Structures on Earth are analogues for features on other planets Seismic reflection a unique tool to study these natural features in 3D Interrogate how surface shape reflects process not as well as assumed? Clues to understanding how other planetary bodies form and evolve See https://tinyurl.com/2p3mx8ae for an extended live version of this presentation