Table 1.

Mare subsurface stratification at five locations, as inferred from LRS data. Apparent depth was determined by the mean of a number of A-scope data (10). The electric properties were estimated by inversely solving a Fresnel model with the assumption that the top-layer material has a dielectric constant of 4. The loss tangent, tan δ, of the lowermost layer was not determined, as the attenuation in that layer is unknown. d and D are the apparent depth and estimated depth to the upper surface of each layer, respectively; P is echo power.

Procellarum (44.5°N, 69.3°W)Imbrium (36.0°N, 15.3°W)Crisium (57.0°N, 15.5°E)Serenitatis (22.0°N, 23.3°E)Smythii (1.0°N, 87.4°E)
Data samples400460330530410
Top layer tan δ 0.001 to 0.019 0.001 to 0.016 0.002 to 0.005 0.001 to 0.019 0.001 to 0.019
Second layer d (m) 320 500 290 350 500
D (m) 160 250 145 175 250
P (dB) -12.2 -12.7 -12.7 -11.4 -12.5
ϵ 5.86 to 8.08 5.77 to 9.04 6.45 to 6.76 6.09 to 8.09 5.82 to 10.68
tan δ 0.001 to 0.010 0.001 to 0.008 0.002
Third layer d (m) 770 1000 660
D (m) 343 to 347 454 to 460 290 to 293
P (dB) -16.0 -15.6 -13.0
ϵ 7.64 to 11.03 7.52 to 11.89 9.25 to 9.71