局所地震のP～S間に見られる顕著なphaseについて

Abstract

Remarkable phases are observed occasionally between P and S waves from local small earth-quakes with S-P times of a few seconds at the Amagase Crustal Movement Observatory. Examiningparticle motions, amplitudes and travel times of these phases, and source locations of the events, they are interpreted as refracted SV and P waves at the boundary of layers in the upper crust.New Amagase telemetry recording system for seismic waves and crustal deformations wasinstalled in April 1977, and digital data have been obtained. The features of recording system andtriggering circuits are described.