Page 40 - Geothermal Energy Systems Exploration, Development, and Utilization

16 1 Reservoir Definition

SDT - Moho+20 km
60°N
P

50°
50°N

40°N
40°

30°N
20°W 0° 20°E
Depth 100 km −9.0−5.4−4.5−3.6−2.7−1.8−0.9 0.0 0.7 1.4 2.1 2.8 3.5 4.2 7.0
S
SRT - Moho+20 km
60°N

50°

50°N

40°
40°N

30°N
350° 0° 10° 20° 20°W 0° 20°E
−9.0−5.4−4.5−3.6−2.7−1.8−0.9 0.0 0.7 1.4 2.1 2.8 3.5 4.2 7.0
0 500 1000 1500
Temperature (°C)
Figure 1.9 Left: Temperatures at 100 km (Shapiro and Ritzwoller, 2002); top: diffrac-
depth estimated from the P and S velocity tion tomography, bottom: ray tomography.
anomalies. (After Goes et al., 2000.) (Please find a color version of this figure on
Right: Tomographic models extracted from the color plates.)
an upper mantle shear velocity model

their surface signatures would be associated with local mantle upwellings (Goes,
Spakman, and Bijwaard, 1999; Guillou-Frottier et al., 2007), thus reinforcing the
possible increase in underlying heat flow. For the FMC area, Lucazeau, Vasseur, and
Bayer (1984) used distinct geophysical data to build a thermal model and concluded
that an additional heat flow contribution from the mantle of 25–30 mW m −2 can
explain surface heat flow data. While a mantle heat flow of 40 mW m −2 is present
in the vicinity of the FMC, it would locally reach 70 mW m −2 beneath parts of the
FMC where a thin crust is seismically detected.