Anomalously Large Ground Motion in the 2016<i>M</i><sub>L</sub> 6.6 Meinong, Taiwan, Earthquake: A Synergy Effect of Source Rupture and Site Amplification

Lee, Shiann‐Jong; Yeh, Te Yang; Lin, Yu-Tsan

doi:10.1785/0220160082

Cited by 49 publications

(59 citation statements)

References 17 publications

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“…Note that the local slip function is very short, 0.5 -1 s, on most subfaults. This slip distribution is in general similar to that obtained by Lee et al (2016) data were jointly used. Figure 4e shows the distribution of stress drop with the average of about 1 MPa, but the absolute value depends on the assumed rupture speed.…”

Section: Teleseismic Body-wave Inversionsupporting

confidence: 80%

“…sinica.edu.tw) and determine the long-period characteristics up to a period of 150 s. The method is described in Kanamori and Rivera (2008), but for applications to moderate regional events, we use a structure shown in Figure 3 shows the result. The best double-couple solution is given by strike/dip/rake (s/d/r) = 295°/30°/37° and 172°/73°/115° and is similar to those obtained by various investigators using different methods, different data sets, and different frequency bands [e.g., Huang et al (2016), Lee et al (2016), also http://tesis.earth.sinica.edu.tw/showDetail. php?date=%272016-02-06%27&time=%2703:57:27%27].…”

Section: W Phase Inversionsupporting

confidence: 80%

“…For comparison, the waveforms at W21B and MASB are shown on the left side of the figure. The slip model derived from a data set including local seismic data by Lee et al (2016) suggests stronger westward directivity.…”

Section: Directivitymentioning

confidence: 97%

“…From the waveform inversion alone, we cannot determine which of the 2 nodal panes is the fault plane. The analyses by Huang et al (2016) and Lee et al (2016) suggest that the static horizontal displacement field appears to favor the north-dipping nodal plane as the fault plane. The rake angle and the slip function are shown on each 4 × 4 km 2 subfault.…”

Section: Teleseismic Body-wave Inversionmentioning

confidence: 98%

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

Kanamori¹,

Ye²,

Huang³

et al. 2017

Terr. Atmos. Ocean. Sci.

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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.

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Section: Teleseismic Body-wave Inversionsupporting

confidence: 80%

Section: W Phase Inversionsupporting

confidence: 80%

Section: Directivitymentioning

confidence: 97%

Section: Teleseismic Body-wave Inversionmentioning

confidence: 98%

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

Kanamori¹,

Ye²,

Huang³

et al. 2017

Terr. Atmos. Ocean. Sci.

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“…Late response of radon increase at this monitoring station is indicative of the fact that the stress distribution for this earthquake was more towards the Western side. It is also to be noticed that the higher local intensity at the location of monitoring stations was found at the Western part than the Eastern part of Taiwan (Lee et al 2016;Wu et al 2016). It is also associated with the larger ground acceleration recorded in the Western part during the Meinong earthquake.…”

Section: Resultsmentioning

confidence: 92%

Preseismic anomalies in soil-gas radon associated with 2016 M 6.6 Meinong earthquake, Southern Taiwan

Fu¹,

Walia²,

Yang³

et al. 2017

Terr. Atmos. Ocean. Sci.

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Taiwan is tectonically situated in a terrain resulting from the oblique collision between the Philippine Sea plate and the continental margin of the Asiatic plate, with a continuous stress causing the density of strong-moderate earthquakes and regional active faults. The continuous time series of soil radon for earthquake studies have been recorded and some significant variations associated with strong earthquakes have been observed. Earthquake prediction is not still operative but these correlations should be added to the literature about seismo-geochemical transients associated to strong earthquakes. Rain-pore pressure related variations, crustal weakness at the studied faults system is consistent with the simultaneous radon anomalies observed. During the observations, a significant increase of soil radon concentrations was observed at Chunglun-T1 (CL-T1), Hsinhua (HH), Pingtung (PT), and Chihshan (CS) stations approximately two weeks before the Meinong earthquake (M L = 6.6, 6 February 2016) in Southern Taiwan. The precursory changes in a multi-stations array may reflect the preparation stage of a large earthquake. Precursory signals are observed simultaneously and it can apply certain algorithms the approximate location and magnitude of the impending earthquake.

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Rupture characteristics of the 2016 Meinong earthquake revealed by the back projection and directivity analysis of teleseismic broadband waveforms

Jian

Hung

Meng

et al. 2017

Geophysical Research Letters

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The 2016 Mw 6.4 Meinong earthquake struck a previously unrecognized fault zone in midcrust beneath south Taiwan and inflicted heavy causalities in the populated Tainan City about 30 km northwest of the epicenter. Because of its relatively short rupture duration and P wave trains contaminated by large‐amplitude depth phases and reverberations generated in the source region, accurate characterization of the rupture process and source properties for such a shallow strong earthquake remains challenging. Here we present a first high‐resolution MUltiple SIgnal Classification back projection source image by using both P and depth‐phase sP waves recorded at two large and dense arrays to understand the source behavior and consequent hazards of this peculiar catastrophic event. The results further corroborated by the directivity analysis indicate a unilateral rupture propagating northwestward and slightly downward on the shallow NE‐dipping fault plane. The source radiation process is primarily characterized by one single peak, ~7 s duration, with a total rupture length of ~17 km and average rupture speed of 2.4 km/s. The rupture terminated immediately east of the prominent off‐fault aftershock cluster about 20 km northwest of the hypocenter. Synergistic amplification of ground shaking by the directivity and strong excitation of sP and reverberations mainly caused the destruction concentrated in the area further to the northwest away from the rupture zone.

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Anomalously Large Ground Motion in the 2016M_L 6.6 Meinong, Taiwan, Earthquake: A Synergy Effect of Source Rupture and Site Amplification

Cited by 49 publications

References 17 publications

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

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

Preseismic anomalies in soil-gas radon associated with 2016 M 6.6 Meinong earthquake, Southern Taiwan

Rupture characteristics of the 2016 Meinong earthquake revealed by the back projection and directivity analysis of teleseismic broadband waveforms

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Anomalously Large Ground Motion in the 2016ML 6.6 Meinong, Taiwan, Earthquake: A Synergy Effect of Source Rupture and Site Amplification

Cited by 49 publications

References 17 publications

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

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

Preseismic anomalies in soil-gas radon associated with 2016 M 6.6 Meinong earthquake, Southern Taiwan

Rupture characteristics of the 2016 Meinong earthquake revealed by the back projection and directivity analysis of teleseismic broadband waveforms

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Anomalously Large Ground Motion in the 2016M_L 6.6 Meinong, Taiwan, Earthquake: A Synergy Effect of Source Rupture and Site Amplification