CaltechAUTHORS
  A Caltech Library Service

Basin Effects in Strong Ground Motion: A Case Study from the 2015 Gorkha, Nepal, Earthquake

Ayoubi, Peyman and Asimaki, Domniki and Mohammadi, Kami (2018) Basin Effects in Strong Ground Motion: A Case Study from the 2015 Gorkha, Nepal, Earthquake. In: Geotechnical Earthquake Engineering and Soil Dynamics V: Seismic Hazard Analysis, Earthquake Ground Motions, and Regional-Scale Assessment. Geotechnical Special Publication. No.GSP 291. American Society of Civil Engineers , New York, NY, pp. 288-296. ISBN 9780784481462. http://resolver.caltech.edu/CaltechAUTHORS:20180629-082818097

[img] PDF - Accepted Version
See Usage Policy.

1762Kb
[img] PDF - Submitted Version
See Usage Policy.

1762Kb

Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20180629-082818097

Abstract

The term "basin effects" refers to entrapment and reverberation of earthquake waves in soft sedimentary deposits underlain by concave basement rock structures. Basin effects can significantly affect the amplitude, frequency, and duration of strong ground motion, while the cone-like geometry of the basin edges gives rise to large amplitude surface waves through seismic wave diffraction and energy focusing, a well-known characteristic of basin effects. In this research, we study the role of basin effects in the mainshock ground motion data recorded at the Kathmandu Basin, Nepal, during the 2015 M_w7.8 Gorkha earthquake sequence. We specifically try to understand the source of the unusual low frequency reverberating pulse that appeared systematically across the basin, and the unexpected depletion of the ground surface motions from high frequency components, especially away from the basin edges. In order to do that we study the response of a 2D cross section of Kathmandu Basin subjected to vertically propagating plane SV waves. Despite the scarcity of geotechnical information and of strong ground motion recordings, we show that an idealized plane-strain elastic model with a simplified layered velocity structure can capture surprisingly well the low frequency components of the basin ground response. We finally couple the 2D elastic simulation with a 1D nonlinear analysis of the shallow basin sediments. The 1D nonlinear approximation shows improved performance over a larger frequency range relative to the first order approximation of a 2D elastic layered basin response.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://dx.doi.org/10.1061/9780784481462.028DOIArticle
https://arxiv.org/abs/1807.00950arXivDiscussion Paper
ORCID:
AuthorORCID
Ayoubi, Peyman0000-0001-6795-4923
Asimaki, Domniki0000-0002-3008-8088
Contact Email Address:ayoubi@caltech.edu
Additional Information:© 2018 American Society of Civil Engineers.
Subject Keywords:Basin effects, Kathmandu Basin, Gorkha Earthquake
Record Number:CaltechAUTHORS:20180629-082818097
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180629-082818097
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87464
Collection:CaltechAUTHORS
Deposited By: Peyman Ayoubi
Deposited On:29 Jun 2018 17:45
Last Modified:22 May 2019 22:01

Repository Staff Only: item control page