Remote Sensing Seismology
When
Where
Dr. Paul Sava
Professor and Department Head, Geophysics
Colorado School of Mines
Remote Sensing Seismology
The interior structures of small planetary bodies hold clues about their origin and evolution, facilitating an understanding of the solar system’s formation, informing exploration for in-situ natural resources, and supporting methods for deflecting or disrupting hazardous near-Earth objects.
High-resolution geophysical interior imaging of small bodies can exploit either radar or seismic waves for dielectric or mechanical properties, respectively. Radar sensing is efficiently done remotely but cannot penetrate deep inside rocky (conductive) bodies, thus limiting its applicability. Conventional seismology can monitor waves propagating inside rocky bodies but needs costly landed instruments, which is why seismology has never been used on small planetary bodies for its cost, risk, and complexity.
In this talk, I describe an alternative form of seismic investigation using Remote Sensing Seismometers built on the principles of laser Doppler vibrometry. Such seismometers can remotely sense motion in the seismic frequency band using coherent laser beams reflected off the investigated body. They can be mounted on orbiters, transforming seismology into a remote sensing investigation, comparable to making visual, thermal, or electromagnetic observations from space.
Remote Sensing Seismometers are superior to landed seismometers as they:
- take measurements from orbit, thus avoiding expensive landers,
- do not need mechanical ground coupling, thus avoiding anchors,
- have a simple electronic design, without fragile mechanical components,
- are mobile and can measure the ground motion at distributed locations,
- operate from robust orbital platforms, thus being shielded from noise.
The dense data sampling provided by Remote Sensing Seismometers enables high-resolution imaging using best-in-class seismic tomography. The radar and seismic remote sensing techniques are complementary and could form the basis of a planetary geophysical tomograph revealing the detailed 3D internal structure and petrophysics of small planetary bodies.
Host: Dr. Erik Asphaug