Location
San Diego, California
Presentation Date
29 May 2010, 8:00 am - 9:30 am
Abstract
Very large vertical surface acceleration of nearly four times gravity was measured at a strong motion observation station in Iwate Prefecture during the 2008 Iwate-Miyagi Inland, Japan, earthquake (Mw 6.9). The station is located about 3 km southwest of the epicenter and equipped with three-component accelerometers, installed at both the free surface and the bottom of a 260-m borehole. The wave form of the vertical acceleration shows a clearly asymmetric form with large amplitude in the upward direction. Aoi et al. (2008) reported and qualitatively explained the mechanism of this phenomenon by the analogy of bouncing a piece of matter on a trampoline, and thus they called it the “trampoline effect.” To simulate this recently discovered nonlinear behavior of the surface ground motion, numerical analysis with a finite-element method has been employed with parameters derived from the borehole data at the station. The analysis successfully simulates the asymmetric vertical motion. Results indicate that the asymmetric motion may be characterized by the existence of a lower bound of negative acceleration, which in most cases corresponds to the acceleration of gravity, and high positive pulses caused by the compression stress of the disturbed surface ground material.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
5th International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Publisher
Missouri University of Science and Technology
Document Version
Final Version
Rights
© 2010 Missouri University of Science and Technology, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Tobita, Tetsuo; Iai, Susumu; and Iwata, Tomotaka, "Numerical Analysis of Trampoline Effect in Extreme Ground Motion" (2010). International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics. 12.
https://scholarsmine.mst.edu/icrageesd/05icrageesd/session03/12
Included in
Numerical Analysis of Trampoline Effect in Extreme Ground Motion
San Diego, California
Very large vertical surface acceleration of nearly four times gravity was measured at a strong motion observation station in Iwate Prefecture during the 2008 Iwate-Miyagi Inland, Japan, earthquake (Mw 6.9). The station is located about 3 km southwest of the epicenter and equipped with three-component accelerometers, installed at both the free surface and the bottom of a 260-m borehole. The wave form of the vertical acceleration shows a clearly asymmetric form with large amplitude in the upward direction. Aoi et al. (2008) reported and qualitatively explained the mechanism of this phenomenon by the analogy of bouncing a piece of matter on a trampoline, and thus they called it the “trampoline effect.” To simulate this recently discovered nonlinear behavior of the surface ground motion, numerical analysis with a finite-element method has been employed with parameters derived from the borehole data at the station. The analysis successfully simulates the asymmetric vertical motion. Results indicate that the asymmetric motion may be characterized by the existence of a lower bound of negative acceleration, which in most cases corresponds to the acceleration of gravity, and high positive pulses caused by the compression stress of the disturbed surface ground material.
