1997 Fiscal Year Final Research Report Summary
A Study on the Effect of Deep Sedimentary Layrs below the Plain on Earthquake Motions
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants |
|Research Institution||Osaka Institute of Technology |
OHBA Shintaro Osaka Institute of Technology, Engineering, Professor -> 大阪工業大学, 工学部, 教授 (50079521)
|Project Period (FY)
1996 – 1997
|Keywords||Earthquake Observation / Earthquake motion / Sedimentary layr / Predominant period / Duration time / 1995 Hyogoken-Nanbu Earthquake / Range of longer period / Sedimentary plain|
This study mainly covered the influence of deep sedimentary layrs on earthquake motion characteristics, based on observation records taken from the 1995 Hyogoken-Nanbu Earthquake (Magnitude 7.2) and the 1997 March 16th Aichiken Toubu Earthquake with a magnitude of 5.8 in the Osaka Plain, Nara basin and nearly plains. Earthquake observation results show that earthquake motion characteristics in a sedimentary plain surrounded by mountains are greatly influenced by the scale of plain and magnitude of the earthquake motions.
The analysis of these observations are summarized as follows :
1)The range of longer period above 1.0 sec.is dependent upon the magnitude of earthquake motions and the thickness of the sedimentary layr. The predominant period increases with the increase in magnitude and depth of layrs.
2)The range of shorter prevailing periods under 1.0 sec.is dependent upon the thickness of sedimentary layr within a depth of approx.100 meters.
3)The predominant period in the Osaka Plain is longer than that in the Nara Basin, which has a thinner sedimentary layr. In the case of the Hyogoken-Nanbu Earthquake which has a magnitude of 7.2, the predominant period was 4.0 sec.in the Osaka Plan, and 2.5 sec.in the Nara Basin.
4)The duration time of earthquake motion in a sedimentary plain depends on size of plain particularly the area. The duration time in the Osaka Plain is more than twice that of the Nara Basin, which has a smaller area.
Research Products (14 results)