Using Gravity as a Proxy for Strain Accumulation in Complex Fault Networks

The gravity signal contains information regarding changes in density at all depths and we suggest it can be used as a proxy for strain accumulation in complex fault networks. Within stike slip systems, such as the San Andreas Fault (SAF) network, our model shows that the dilatational gravity signal highs are coincident with subsequently faulting segments when using stress evolution simulations or known slip histories. In addition, the dilatational gravity signals are well within in the range of portable instrumentation, and yield signals ranging from approximately ±15--75μGal; dip slip system yield even higher values. In addition, the complexity of the fault geometry is shown to control the spatial distribution of the gravity signals observed and the signals' magnitude are constrained by the amount slip modeled.