principles and applications of microearthquake networks

6.2. Frrult-Plutie Solution 139
(1980). We expect that many techniques resulting from these advances
will be applied to microearthquake data in the near future.
6.2. Fault-Plane Solution
The elastic rebound theory of Reid (1910) is commonly accepted as an
explanation of how most earthquakes are generated. This theory has been
concisely described by Stauder (1 962, p, 1) as follows: earthquakes
occur in regions of the earth that are undergoing deformation. Energy is
stored in the form of elastic strain as the region is deformed. This process
continues until the accumulated strain exceeds the strength of the rock,
and then fracture or faulting occurs. The opposite sides of the fault rebound
to a new equilibrium position, and the energy is released in the
vibrations of seismic waves and in heating and crushing of the rock. If
earthquakes are caused by faulting, it is possible to deduce the nature of
faulting from an adequate set of seismograms, -and in turn, the nature of
the stresses that deform the region.
Let us now consider a simple earthquake mechanism as suggested by
the 1906 San Francisco earthquake. Figure 26 illustrates in plan view a
Fig. 26. Plan view of the distribution of compressions ( + ) and dilatations (-) resulting
from a right lateral displacement along a vertical fault FF'.