Despite the countless observations of foreshocks before many large earthquakes, the mechanism responsible for their occurrence remains under debate. Moreover, the physical relationship between foreshocks and mainshocks remains uncertain. We investigate whether or not the protracted nucleation process of the mainshock, and thereby the relative timing of smaller-scale earthquakes (intershocks), affects the source properties of these precursory events. Any characteristic features of the source properties may help us identify events as foreshocks as they happen, in order to determine whether the smaller-scale earthquake has information about the upcoming mainshock. If the advancement of the upcoming mainshock is indeed noticeably manifested in the source properties of foreshocks, then this understanding could be a key ingredient in the potential development of a mechanics-based earthquake forecasting method.
This work is also in collaboration with University of Toronto Mississauga.