HR: 0830h
AN: P31B-1059    [PDF]
TI: GPR Measurements at Planetary Analog Sites in Northern Arizona
AU: * Williams, K K
EM: williamsk@nasm.si.edu
AF: Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560 United States
AU: Grant, J A
AF: Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560 United States
AU: Schutz, A E
AF: Geophysical Survey Systems, Inc., 13 Klein Drive, North Salem, NH 03073 United States
AB: Ground penetrating radar (GPR) operating at frequencies generally between 100-1000 MHz can penetrate up to 10-20 m to reveal information regarding the dielectric properties of the subsurface. This information provides insight into subsurface geologic structure and setting. The ability to remotely sense the subsurface structure of an area without drilling or excavating has proven economical and, in some cases, invaluable in civil engineering and geological applications on Earth. In recognition of the benefits of a GPR on potential future rovers and landed missions to the Moon, Mars, or other solar system body, fieldwork has been conducted to assess GPR data of volcanic, cratered, and other analog settings in northern Arizona. Measurements were made at Sunset Crater, Meteor Crater, and the 2002 FIDO rover test site near Cameron, AZ. At each site, data were collected using commercial GPR antennas at 400 MHz, 500 MHz, and 1.5 GHz as well as a 600 MHz prototype planetary GPR antenna. For comparison, shallow seismic data were also collected along some of the GPR tracks, In these Mars analog terrains, GPR data reveal subsurface interfaces that are useful for understanding the geologic history at those sites. Interfaces in the data collected at Sunset Crater help delineate several episodes of cinder deposition that mantle the surface of a lava flow. At Meteor Crater, the thickness of distal portions of the ejecta blanket can be estimated where the GPR penetrated through to the pre-impact surface. At the FIDO site, data indicate local fluvial systems are incised into coherent bedrock rather than older channel fill, thereby highlighting the stripped nature of the setting. GPR data collected in these three different geologic settings demonstrate the ability of ground penetrating radar to provide information about subsurface geology through non-invasive techniques. The ability to remotely sense the shallow subsurface is especially desirable for Mars rover missions planned for the next decade because direct sampling via drilling to depths up to 20 m may not be possible.
DE: 5109 Magnetic and electrical properties
DE: 5470 Surface materials and properties
DE: 5494 Instruments and techniques
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting