2-Dimensional Examples

Abstract

We present forward 2-dimensional modeled velocities and VDoHS rates for strike-slip faults, dip-slip faults, and a Mogi source. Results for 2-dimensional profiles across infinite length faults are equivalent to the corresponding 1-dimensional results. Finite length faults give velocity patterns that are strongly influenced by the fault truncations; however, the VDoHS rates are much less affected. In all cases the VDoHS rates are much more localized than the velocities or strain rates. In complex settings, such as a rift example containing multiple closely spaced normal faults and a Mogi source with very low velocity signals, even perfect sampling and no observational errors lead to strain rates that make it difficult to discern all the deformation sources. Discerning the sources with VDoHS rates is feasible, but requires GPS station spacing of the order of half the depth of the deformation source for GPS errors of ~0.2 mm/year. Such GPS errors are achievable today with some continuous GPS networks. Finally we note that halving the data standard errors has much the same effect as halving the station spacing. Therefore, for campaign GPS data, where standard errors tend to be large at 0.5–1 mm/year, detection of individual sources requires either proportionally smaller GPS stations spacing or larger surface source signals.