HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Electronic Supplement Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Furumura, T. Articles by Hayakawa, T. Search for Related Content GeoRef GeoRef Citation

Anomalous Propagation of Long-Period Ground Motions Recorded in Tokyo during the 23 October 2004 M_w 6.6 Niigata-ken Chuetsu, Japan, Earthquake

¹ Earthquake Research Institute
University of Tokyo
1-1-1 Yayoi, Bunkyo-ku, 113-0032, Japan
furumura{at}eri.u-tokyo.ac.jp
t-haya{at}eri.u-tokyo.ac.jp

Unusually large (>5 cm) and prolonged shaking associated with long- period ground motions at periods of about 7 sec were observed in central Tokyo during the M_w 6.6 Niigata-ken Chuetsu earthquake of 23 October 2004. The long- period ground motions caused significant resonance in high-rise buildings of about 70 floors in height. Thus, it is an urgent matter to understand the development and amplification properties of long-period ground motions in Tokyo associated with large earthquakes.

In this study, we use numerous waveform records from 585 stations in a nationwide accelerometer network (K-NET, KiK-net) and 495 intensity meters in the area around Tokyo. The data reveal that the long-period ground motion is characterized in most part by a surface, Rayleigh wave generated at the northern edge of Kanto basin, and the surface wave is developed as propagating through a thick cover of sediments (>3000–4000 m) that overlies rigid bedrock.

To complement the observational data, we conducted a large-scale computer simulation of seismic-wave propagation by employing the Earth Simulator supercomputer with a detailed source-slip model and a high-resolution 3D sedimentary structural model of central Japan. The results of the computer simulation demonstrate that the anomalously prolonged ground shaking of the long-period signal recorded in the center of Tokyo occurred because of the stagnation of seismic energy resulting from the multipathing and focusing of Rayleigh waves toward the bottom of the Kanto basin from surrounding mountain regions with interaction to the 3D basin structure.

Online material: Animations of long-period ground motions in Tokyo.

This article has been cited by other articles:

				M. Stupazzini, R. Paolucci, and H. Igel Near-Fault Earthquake Ground-Motion Simulation in the Grenoble Valley by a High-Performance Spectral Element Code Bulletin of the Seismological Society of America, February 1, 2009; 99(1): 286 - 301. [Abstract] [Full Text] [PDF]