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A strong-motion hot spot of the 2016 Meinong, Taiwan, earthquake (M_w = 6.4)

Kanamori, Hiroo and Ye, Lingling and Huang, Bor-Shouh and Huang, Hsin-Hua and Lee, Shiann-Jong and Liang, Wen-Tzong and Lin, Yen-Yu and Ma, Kuo-Fong and Wu, Yih-Min and Yeh, Te-Yang (2017) A strong-motion hot spot of the 2016 Meinong, Taiwan, earthquake (M_w = 6.4). Terrestrial Atmospheric and Oceanic Sciences, 28 (5). pp. 637-650. ISSN 1017-0839. https://resolver.caltech.edu/CaltechAUTHORS:20171109-103411500

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Abstract

Despite a moderate magnitude, M_w = 6.4, the 5 February 2016 Meinong, Taiwan, earthquake caused significant damage in Tainan City and the surrounding areas. Several seismograms display an impulsive S-wave velocity pulse with an amplitude of about 1 m s-1, which is similar to large S-wave pulses recorded for the past several larger damaging earthquakes, such as the 1995 Kobe, Japan, earthquake (M_w = 6.9) and the 1994 Northridge, California, earthquake (M_w = 6.7). The observed PGV in the Tainan area is about 10 times larger than the median PGV of M_w = 6.4 crustal earthquakes in Taiwan. We investigate the cause of the localized strong ground motions. The peak-to-peak ground-motion displacement at the basin sites near Tainan is about 35 times larger than that at a mountain site with a similar epicentral distance. At some frequency bands (0.9 - 1.1 Hz), the amplitude ratio is as large as 200. Using the focal mechanism of this earthquake, typical “soft” and “hard” crustal structures, and directivity inferred from the observed waveforms and the slip distribution, we show that the combined effect yields an amplitude ratio of 17 to 34. The larger amplitude ratios at higher frequency bands can be probably due to the effects of complex 3-D basin structures. The result indicates that even from a moderate event, if these effects simultaneously work together toward amplifying ground motions, the extremely large ground motions as observed in Tainan can occur. Such occurrences should be taken into consideration in hazard mitigation measures in the place with frequent moderate earthquakes.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3319/TAO.2016.10.07.01DOIArticle
http://tao.cgu.org.tw/index.php/articles/archive/geophysics/item/1511PublisherArticle
ORCID:
AuthorORCID
Kanamori, Hiroo0000-0001-8219-9428
Ye, Lingling0000-0002-8739-2072
Huang, Hsin-Hua0000-0002-1115-2427
Lin, Yen-Yu0000-0002-6971-3960
Additional Information:© 2017 Chinese Geoscience Union. Received 25 July 2016; Revised 6 October 2016; Accepted 7 October 2016. The Data Management System of the Incorporated Research Institutions for Seismology (http://www.iris.edu/hq/) was used to access the seismic data from the Global Seismic Network and Federation of Digital Seismic Network stations. We thank Thorne Lay for providing us with useful suggestions on inversion of teleseismic data and Luis Rivera for helping us to use the Hermann’s frequency-wavenumber integration code. We benefited from the discussion with The-Ru Alex Song in the early stage of this work. Part of this research was conducted while Hiroo Kanamori was visiting the Institute of Earth Sciences, Academia Sinica under the Distinguished Visiting Fellow program of Academia Sinica. We thank two anonymous reviewers for helpful comments.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
Academia SinicaUNSPECIFIED
Subject Keywords:2016 Meinong earthquake, Directivity, Site response, S-wave pulse
Issue or Number:5
Record Number:CaltechAUTHORS:20171109-103411500
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20171109-103411500
Official Citation:H.-H. Huang, S.-J. Lee, W.-T. Liang, Y.-Y. Lin, K.-F. Ma, Y.-M. Wu, and T.-Y. Yeh, 2017: A strong-motion hot spot of the 2016 Meinong, Taiwan, earthquake (Mw = 6.4). Terr. Atmos. Ocean. Sci., 28, 637-650, doi: 10.3319/TAO.2016.10.07.01
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:83103
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Nov 2017 22:49
Last Modified:09 Mar 2020 13:19

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