C-1: Prediction of Strong Earthquake Ground Motions,
Earthquake Disaster Prediction and Mitigation
This research group has four sub-theme programs. These are as follows.
1)Prediction of seismic activity in Hebei region
2)Prediction of strong earthquake ground motions in Tangshan region
3)Seismic risk assessment of urban region
4)Urban planning against strong earthquake.
Research activities and programs in this year are as follows
Prediction of Seismic Activity in Hebei Region
A five-year joint program on prediction of seismic activity in the Heibei Region is conducted under the joint research agreement between DPRI and Institute of Geophysics, SSB. This program aims to present a method to identify anomalous seismic activities from the daily and long-term seismic activities of the Heibe region. The term "earthquake activity" denotes in this program that it does not attempt to make prognoses of individual events, but forecast activity of seismicity level as a whole. In order to make a prediction of seismicity we will set up a continuous recording system at the Institute of Geophysics to obtain data from some selected stations. The continuous recording system has several advantages relative to the triggered System in the following points, we can 1)avoid mistriggering of earthquakes, 2)record anomalous events which are missed with ordinary triggering logic, 3)and get valuable information on the fine structure of the earth's interiors.
In this year, M. Ando and K. Hirahara are scheduled to visit the Institute of Geophysics to discuss on the joint program subjects. And one researcher from the Institute of Geophysics, SSB, will be coming to DPRI, Kyoto Univ. to make a further progress on the project.
Prediction of Strong Ground Motions in Tangshan Region
A five-year joint research program on prediction of strong ground motions is being conducted under the joint research agreement between DPRI and IEM(Institute of Engineering Mechanics, State Seismological Bureau, China). The cooperative activities to be conducted under the agreement are as follows: 1)Study on the effects of earthquake source, wave path and surface geology on seismic motion based on small to large earthquake motion observations and geotechnical measurements. 2)Study on strong ground motion prediction and its verification by using data of Strong motions and earthquake damages. Seismic observations for strong motions are being conducted in Tangshan region since 1992. The seismic network now consists of four stations. The station will be increased up to six stations by Mr. K. Matsunami of DPRI, who will visit China this year. The main theme of this year are to investigate seismic wave attenuation and site effects on seismic motion by using data observed by our seismic network at Tangshan region.
Seismic Risk Assessment of Urban Region
The joint research agreement between DPRI and the Seismological Bureau of Yunnan Province(YSB), state Seismological Bureau, was exchanged in May, 1955.
Although exchanging the agreement had been delayed because of the Hanshin-Awaji great Disaster caused by the 1995 Hyogoken-nanbu Earthquake, the international joint research on seismic risk assessment in an urban area on soft sediment has officially started. A 3-D array observation for strong motion will be carried out at the Western Yunnan Earthquake Prediction Study Area, in Dali. In July 1995, three researchers of YSB including Professor Yan-Feng-Ton, Deputy Director of YSB, Will visit DPRI to discuss the detailed research program. At the same time, a workshop will be held at DPRI on tectonics of Yunnan and seismic risk, and problems in relation to the Hanshin-Awaji Great Disaster.
Urban Planning Against Strong Earthquake
As mentioned in the Newsletter of DPRI, No.2, 1995 Hyogoken-Nanbu earthquake thrusted uncountable valuable problems before the researchers of earthquake engineering allover the world.
Prof. T. Fujiwara was invited from the Earthquake Resistance Office (ERO) of the Ministry of Construction of China on May 20-22,1995. He introduced the severe damages done by this earthquake and discussed with Mr. Liu Zhigang and Mr. Dou Yide, deputy directors of ERO. about the reason of damages and the process of repair and reconstruction of Kobe area. Prof. Su You-po, Dean of Dept. Civil and Arch. Eng., Hebei Institute of Technology and Mr. Liu, general manager of Dept. of Construction, Tangshan city. also attended this meeting, both of them were key persons of joint research project between DPRl and China, Following three main themes were mainly discussed:
1) Control system and isolation system are important research fields on future seismic safety of building structures, especially, buildings useful to emergency.
2) The method of recovery or reconstruction after the severe damage is progressive in Chinese side and it is useful for Hanshin area hit by the earthquake, to make clear the up-to-date problems in Tangshan, where 20 years passed after the Tangshan earthquake.
3) According to Prof. Ye Yaoxian, President of China Building Technology Development Center, brick masonry buildings sterengthened by reiforcing bars and wood frame with brick wall are believed to be ductile in China. We agreed future discussion in detail to be important.
