地壳形变-地震活动的大地测量方法-2014汇编.ppt

Parkfield Earthquake From Jeff Freymueller Separating Coseismic and Postseismic From Jeff Freymueller Parkfield eq J. Langbein, USGS Lessons from Parkfield From Jeff Freymueller ? Postseismic deformation appears to begin immediately after earthquake ? Coseismic and postseismic mechanisms are different ? Almost all “coseismic” estimates include postseismic deformation InSAR vs/+ GPS From Jeff Freymueller ? InSAR does not require pre- earthquake field survey ? Spatially dense measurements ? But only one component, and the impact of the look angle makes for strange “look” ? Minimum ~30 day repeat interval The 2002 Denali Earthquake From Jeff Freymueller The Earthquake From Jeff Freymueller ? November 3, 2002, about 1:30 pm local time ? Mostly ruptured the Denali fault – Also Susitna Glacier fault (thrust) and Totschunda fault (strike-slip) ? Initial estimated magnitude MW 7.9 ? Preceded by MW 6.7 on October 23 ? Preceded by ML ~4.5 foreshock Tectonic setting From Jeff Freymueller Mainshock and Aftershocks From Jeff Freymueller Epicentral Region From Jeff Freymueller Coseismic GPS Sites From Jeff Freymueller Coseismic Displacements at 232 GPS Sites Estimation of Displacements From Jeff Freymueller ? Continuous GPS – Average of 4 days before and after earthquake ? Campaign GPS with well-determined velocities – Linear fit to pre-earthquake data plus displacement – For sites with imprecise velocity, we used a model or interpolation of surrounding sites ? Campaign GPS with no post-earthquake measurements until summer 2003 – Postseismic correction applied based on interpolation of postseismic displacements of surrounding sites. Coseismic Displacements - Horizontal From Jeff Freymueller Two scales (3:1) Coseismic Displacements - Vertical From Jeff Freymueller Modeled Vertical Displacement Field (from GPS data) Richardson Hwy Profile (and the TAPS corridor) From Jeff Freymueller Coseismic Slip Model From Jeff Freymueller Coseismic GPS Sites Fro