Rapid postseismic transients in subduction zones from continuous GPS

摘要: [1] Continuous GPS time series from three of four recently measured, large subduction earthquakes document triggered rapid postseismic fault creep, representing an additional moment release upward 25% over the weeks following their main shocks. Data two Mw = 8.0 and 8.4 events constrain centroids to lie down dip lower limit coseismic faulting, show that afterslip along primary asperities is significantly less important than deep creep. Time for another 7.7 event 30% energy release, but here we cannot differentiate between deeper A fourth 8.1 event, which occurred in broad Chilean seismogenic zone, shows no deformation, despite offsets excess 1 m. For are followed by stress transferred inferred (at 34, 60, 36 km depths) respective shock increased reverse shear 0.5, 0.8, 0.2 bar with a comparatively small decrease normal (0.01 bar), constraining Coulomb increase required force slip metastable plate interface. Deep this nature invisible without continuous geodesy on basis these would appear constitute mode strain beneath zones convergent margins. These events, captured some first permanent networks, often modulated rupture updip underscore need fully quantify spectrum great earthquakes. INDEX TERMS: 7209 Seismology: Earthquake dynamics mechanics; 3040 Marine Geology Geophysics: Plate tectonics (8150, 8155, 8157, 8158); 8150 Tectonophysics: boundary—general (3040); 7230 Seismicity seismotectonics; KEYWORDS: earthquake, postseismic,