Investigation of lunar maria structure from cross-analysis of GRAIL gravity and Kaguya radar data
Abstract
The Lunar Radar Sounder (LRS) on JAXA's Kaguya spacecraft investigated the subsurface structure of the Moon to a depth of a few km. GRAIL gravity models are potentially sensitive to subsurface structure at such depths. GRAIL gravity and LRS radar data are complementary since both are sensitive to density/compositional heterogeneities. Cross-correlation of GRAIL and LRS data has the potential to produce new constraints on the structure and evolution of the lunar maria. Originally, subsurface reflections within the lunar maria were detected with Lunar Sounder Experiment aboard Apollo 17. Subsurface layering was attributed to multiple episodes of volcanism. Later, Kaguya's LRS produced similar measurements but with global-scale coverage. Laboratory measurements show that density variations among mare basalts can be up to 200 kg m-3 or 7%. The LRS measurements have detected subsurface reflection in the upper 1 km of the crust. Combining these two estimates and using the Bouguer slab approximation, we estimate that anomalies of order 1-10 mGal are expected due to potentially varying density of surface and/or subsurface horizons. This accuracy is achievable with the latest GRAIL gravity models. The LRS surface backscattering power is indicative of surface and near sub-surface dielectric properties, which are sensitive to target density and roughness. We investigate the northwestern part of the Procellarum basin because it is the region with the strongest signal-to-noise ratios in gravity models within maria. To examine shallow subsurface structure, we map the surface received power by tracking the first return of radar echoes and compare it with gravity gradients, which are particularly sensitive to small-scale structures.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.P54B..02Z
- Keywords:
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- 6299 General or miscellaneous;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 5464 Remote sensing;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 5470 Surface materials and properties;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 5499 General or miscellaneous;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS