Recent Geodynamics of a Fault System

The repeated leveling observations on the profile intersecting a few fault zones revealed two types of the anomalies in the recent vertical surface displacements in these zones. The anomalous displacement of an isolated type occurs on a single fault. Displacement curves of the mixed type are formed by the superim-position of two or more anomalies induced by the nearby faults. The modeling shows that the interaction between the fault zones ceases at threshold distance S. The observed spectrum of the anomalous vertical motions of the Earth's surface gives S = 1-3.5 km in the model with a fault zone simulated by the inclusion with a width of 2a = similar to 0.15-0.5 km located at a depth ranging from 0.3 to 2.7 km. The simulations with sub-sequent minimization of the misfit between the model predictions and observations on the profile intersecting several faults indicate that a relative variation of 5-11% in the bulk modulus is sufficient for causing vertical surface displacements with an amplitude of 30-50 mm in the vicinity of the fault.