Surface fault ruptures associated with the 14 April foreshock (Mj 6.5) of the 2016 Kumamoto earthquake sequence, southwest Japan

Sugito, Nobuhiko; Goto, Hideaki; Kumahara, Yasuhiro; Tsutsumi, Hiroyuki; Nakata, Takashi; Kagohara, Kyoko; Matsuta, Nobuhisa; Yoshida, Haruka

doi:10.1186/s40623-016-0547-5

Cited by 21 publications

(8 citation statements)

References 2 publications

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“…The features of earthquake-induced surface ruptures mainly include extensional fissures, local uplift, bulging, and subsidence [4][5][6]51]. In this experiment, there are two macroscopic fracturing modes: extensional fissures and local bulging.…”

Section: Fracturing Modementioning

confidence: 95%

“…Rock failure can result in different types of surface fracturing modes, including extensional fissures, local bulging, and subsidence, along active faults [1][2][3]. Hence, basic information on crustal activity, including the deformation mode, motion state of a fault and the fracture process, can be reflected by the movement characteristics of surface rupture [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on the Thermal Infrared Spectral Variation of Fractured Rock

Huang

Liu

et al. 2021

Remote Sensing

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Previous studies have shown that thermal infrared radiation (TIR) anomalies occur in the vicinity of fractures that form when a rock is loaded to failure. Different types of fracturing modes correspond to different TIR anomaly trends. However, the spectral features and the mechanisms responsible for the TIR changes in the fracturing stage remain poorly understood. In this paper, experiments involving observations of the thermal infrared spectrum (8.0–13.0 μm) of loaded sandstone during the fracturing stage were conducted under outdoor conditions. The experiment yielded the following results: (1) Different fracturing modes can lead to different trends in the spectral radiance variation; (2) when an extensional fissure appeared on the rock surface, the radiance increased with a local peak in the 8.0–9.7 μm range; 3) when local bulging formed at the surface, the radiance decreased, with a local valley in the 8.0–9.7 μm range. The radiance variation caused by morphologic changes is the combined result of changes in both the temperature and the emissivity. The characteristic waveband corresponding to the reststrahlen features (RF) of quartz was mainly related to the emissivity change. This study provides a preliminary experimental foundation for the detection of crustal surface fractures via satellite-based remote sensing technology.

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Section: Fracturing Modementioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Thermal Infrared Spectral Variation of Fractured Rock

Huang

Liu

et al. 2021

Remote Sensing

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“…Both ruptures showed right-lateral strike slip displacements of about 50-100 cm with slight uplift of southern side. The surface ruptures were described by topographical field investigations (Shirahama et al, 2016;Sugito, et al, 2016) but also traced clearly from aerial photographs taken after the earthquakes. It is characteristic that both ruptures extend to divide a wedge-shaped lowland where Kiyama and Akitsu River flow through.…”

Section: Study Sitementioning

confidence: 99%

Detailed Near Surface Geophysical Survey at an Area Stricken by the 2016 Kumamoto Earthquakes

Inazaki

Kisanuki

Ogahara

et al. 2018

Symposium on the Application of Geophysics to Engineering and Environmental Problems 2018

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We conducted a detailed near surface geophysical survey at Mashiki Town, Kumamoto Prefecture, western Japan, where was severely damaged by the 2016 Kumamoto twin earthquakes of magnitudes 7.3 as the mainshock and 6.4 as a foreshock. The near surface survey comprised "Hybrid Surface Wave Survey" (HSWS), capacitively coupled resistivity (CCR) measurement using OhmMapper, and GPR measurements using Utility Scan DF or 350 HS tools. A total of 5 short survey lines were set to intersect a branched surface rupture, or placed in the downtown area of Mashiki Town. The purposes of the survey were to assess the usefulness of the above geophysical methods for the delineation of near-surface conditions of such earthen structures as levees and road embankments attacked by strong earthquakes, and to provide high-resolution subsurface profiles of the sites where surface structures were sporadically damaged. Notable results of our study were as follows. First, GPR successfully imaged detailed structures on the surficial zones form 2 m to in case to 5 m in depth. It was characteristic that a number of step-like sharp dislocations were identified around the surface rupture. Layered resistivity structures, concordant with inferred geological structure of the area, were imaged by CCR surveys up to 10 m in depth. HSWS, recently proposed by the authors, reconstructed S-wave structures up to 40 m in depth. In addition, HSWS records were processed through an ordinary seismic reflection data processing flow. As a result, reverse faulting structure was clearly imaged in concordance with the other near-surface survey results.

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“…1a). Significant surface ruptures associated with the earthquake sequence appeared in Mashiki Town, which is located at the junction of the two major fault zones (Shirahama et al 2016;Sugito et al 2016;Toda et al 2016) and seismic intensity of 7, the maximum seismic intensity scale of the Japan Metrological Agency (JMA), was measured during both larger events. The results of damage investigations (e.g., National Institute for Land and Infrastructure Management and Building Research Institute 2016; Sugino et al 2016b;Tomozawa et al 2017;Yamada 2017;Yamada et al 2017a, b) showed that heavily damaged buildings were concentrated in a narrow region between Kumamoto Prefectural Route 28 (R28) and the Akitsu River running from east to west in the central part of Mashiki (Fig.…”

Section: Introductionmentioning

confidence: 99%

Subsurface velocity structure and site amplification characteristics in Mashiki Town, Kumamoto Prefecture, Japan, inferred from microtremor and aftershock recordings of the 2016 Kumamoto earthquakes

Hayashida

Yamada

et al. 2018

Earth Planets Space

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In order to investigate the seismic velocity structure in the region of concentrated severe damage during the 2016 Kumamoto earthquake sequence, we conducted continuous seismic observations in the central area of Mashiki Town, Kumamoto Prefecture. During 4 days of observations at eight temporary sites, 2 months after the mainshock, recordings from 30 aftershocks (1.7 ≤ M j ≤ 4.3, 1.9 km ≤ depth ≤ 13.5 km) were obtained. The aftershock data showed that site amplifications at approximately 1 Hz are dominant in a zone where almost no buildings were damaged along the Akitsu riverside, whereas site amplifications at higher than 3 Hz are observed in the heavily damaged zones. Our data also showed that the peak acceleration and velocity amplitudes, as well as seismic intensities for the small events in the less damaged zone, are clearly larger than those in the damaged zones, implying that the damage distribution is inconsistent with site response based on linear site amplifications. The estimated phase velocities of Rayleigh waves using the aftershock and microtremor data show dispersive characteristics in the lower frequency range (0.26 ≤ f ≤ 1.27 Hz), but the values are substantially smaller than those derived from the P-S logging model at the nearest KiK-net strong-motion observation station KMMH16. The derived microtremor horizontal-to-vertical spectral ratios and earthquake radial-to-vertical (R/V) spectral ratios show common distinct peaks at around 0.4 Hz, which are possibly related to the response of deep sedimentary layers beneath the area. The refined velocity structure model that better accounts for both the phase velocity and common dominant peak indicates that the values of S wave velocity (Vs) above the bedrock layer (Vs = 2700 m/s) are smaller than those inferred from the logging model and the depth to the bedrock layer could be much deeper (about 600 m) in comparison with the logging model (234 m). The derived R/V spectral ratio at station KMMH16 also shows a distinct peak at 0.4 Hz, suggesting that there is no large difference of deep sedimentary structure between the observation area and station KMMH16. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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Surface fault ruptures associated with the 14 April foreshock (Mj 6.5) of the 2016 Kumamoto earthquake sequence, southwest Japan

Cited by 21 publications

References 2 publications

Experimental Study on the Thermal Infrared Spectral Variation of Fractured Rock

Experimental Study on the Thermal Infrared Spectral Variation of Fractured Rock

Detailed Near Surface Geophysical Survey at an Area Stricken by the 2016 Kumamoto Earthquakes

Subsurface velocity structure and site amplification characteristics in Mashiki Town, Kumamoto Prefecture, Japan, inferred from microtremor and aftershock recordings of the 2016 Kumamoto earthquakes

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