Tectonic Movement, Deformation Release and Crustal Structure Studies in AlASKA

摘要

The seismic telemeter system data now cover a total of three years record for central Alaska. Monthly epicenter maps for the contract period are given. The tectonic pressure axis have been determined using earthquakes occurring in the network. Three borehole packages of the USO type have been installed in Gilmore, Paxson and McKinley. It was found that the construction of the long-period part of the borehole package makes the LP-X component a very sensitive microbarograph, covering the period range from 15 sec to DC. Tilts associated with local earthquakes of small magnitude at short distances are discussed. Laboratory results on brittle rock failure seem to be valid for the earth crust. If foreshocks occur at all, the 'b' slope of the Gutenberg-Richter Relation, linking the log of the number to the magnitude of the earthquakes, seem to indicate high average stress levels for small areas and prior to a small main shock, the larger areas associated with relatively stronger earthquakes seem to be associated with lower average stress levels. (Author)