Crustal Structure in the Profile Across the Northeastern Part of Honshu, Japan, as Derived from Explosion Seismic Observations

Part 2. Crustal Structure

Abstract

The crustal structure in a profile crossing the northeastern part of Honshu, Japan, is derived from the data obtained in the Off Kesennuma, the Off Oga Peninsula and the Tutihata explosions. The fixed array-moving shot point technique was first applied in this profile, and more than 600 seismograms were obtained. Assuming a homogeneous layered structure, the thickness of the crust in the central mountain area was obtained as 30km. The crust tapers near the shore toward the ocean on both sides of Honshu, and the transition of crustal structure from the continental to the oceanic seems to occur in the vicinity of Honshu. The existence of the basaltic layer and the value of 8.0km/s for P_n velocity became more convincing through the analysis of this profile.