Paths Forward to Understanding and Managing Induced Seismicity in Energy Technology Development - Induced Seismicity Potential in Energy Technologies - page 121

FIGURE 5.2 Cross section of the Earth illustrating the maximum distance that minor (or greater) shaking
will occur, for tectonic earthquakes originating at 10 km (6 miles) depth, with M 3 (green line), 4 (yellow
line), and 5 (red line). In this example, only M 5 earthquakes will generate shaking that is felt at the surface.
FIGURE 5.3 Cross section of the Earth illustrating maximum distance that minor (or greater) shaking will
occur, for both natural and induced earthquakes originating at 2 km (1.2 miles) depth, with M 3 (green
line), 4 (yellow line), and 5 (red line). The diagram depicts an induced earthquake at the bottom of a well.
Because of the shallow depth, each of these earthquake magnitudes would generate shaking at the surface
that could be felt. Because of the larger energy released, a M 5 earthquake would be felt over a much
greater area of the surface (up to 20 km [12 miles]) from the well, whereas a M 3 earthquake would only
be felt about 1 km (0.6 miles) from the well.
damaged, and net changes to subsurface pore pressure caused by the energy project. These
net changes involve the volume and pressure of fluids injected or extracted, the duration of
injection and extraction, and the number of wells involved in the project. Note that these
variables may be related; that is, the total fluid volume depends on the duration of injection
or extraction and the number of wells involved.