3D Surface Displacement and Surface Ruptures Associated with the 2014 Mw 6.2 Nagano Earthquake Using Differential Lidar

Ishimura, Daisuke; Toda, Shinji; Mukoyama, Sakae; Homma, Shinichi; Yamaguchi, Kyoko; Takahashi, Naoya

doi:10.1785/0120180020

Cited by 14 publications

(24 citation statements)

References 37 publications

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“…7). Simple subtraction allows us to estimate the dip slip of the PE to be 1.7 ± 0.3 m and that of the APE to be 2.9 ± 0.5 m. Since the dip slip of the most recent event at Oide was 1.2 ± 0.1 m (Ishimura et al, 2019), the slip of the PE was a little larger than that of the 2014 event. Similar conclusions are given by Katsube et al (2017), that is, the PE showed a slightly smaller displacement than the 2014 slip on the paleoseismic trench walls in the center of the 2014 surface rupture zone (Iimori site in Fig.…”

Section: Cumulative Dip Slip Of Mapped Terracesmentioning

confidence: 97%

“…This is because Okumura identified events based on angular unconformity, which is probably insensitive to small displacements near the surface. The fact that Okumura's trench sites experienced a broad uplift (~ 20-30 cm) without any apparent surface break (Ishimura et al, 2019) also justifies our choice of the minimum value. The maximum simulated slip limit is based on a compilation of paleoearthquake records at 42 sites over the entire ISTL (Maruyama et al, 2010).…”

Section: Inter-event Variability In Coseismic Slip At Oidementioning

confidence: 97%

“…This study presents a method for exploring inter-event variability in coseismic slips at a site using a displaced terrace sequence across the Kamishiro Fault. A 9 km-long section to the north of the Kamishiro Fault was ruptured by the Nagano-ken-hokubu earthquake (Mw = 6.2) on November 22, 2014, which caused a vertical displacement of up to 1 m (e.g., Okada et al, 2015;Ishimura et al, 2019). We first mapped the fluvial terraces and measured the cumulative dip slip following a semiautomated method developed by Wolfe et al (2020).…”

Section: Introductionmentioning

confidence: 99%

“…During the 2014 earthquake, surface ruptures appeared mainly along the preexisting fault scarp and were accompanied by minor secondary faulting, such as flexure deformation and rupture on branch faults(Okada et al, 2015;Ishimura et al, 2019). The total amount of dip slip at Oide was 1.2 ± 0.1 m, which corresponds with the maximum value over the entire rupture area(Ishimura et al, 2019). Therefore, the paleoseismic record of the Oide site should be representative of the Kamishiro Fault.…”

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confidence: 98%

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Evaluating variability in coseismic slips of paleo-earthquakes using a flight of displaced terraces across the Kamishiro fault, Itoigawa-Shizuoka Tectonic Line, central Japan

Takahashi

Toda

2020

Preprint

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Examining the regularity between events during an earthquake slip leads to an understanding of earthquake recurrence and provides the basis for probabilistic seismic hazard assessment. Generally, scientists use systematic analysis of three-dimensional paleoseismic trenches and numerous offset markers along fault zones to study slip history. Flights of displaced terraces have also been used, under the assumption that the number of earthquakes contributing to the observed cumulative slip is known. This study presents a Monte Carlo-based approach to estimating slip variability from a series of displaced terraces when such an assumption cannot be satisfied. First, we mapped fluvial terraces across the Kamishiro Fault, which is an intra-plate reverse fault in central Japan, and systematically measured the cumulative net slip in the mapped terraces. By combining these measurements with the age of the paleoearthquakes, we estimated the amount of net slip for the penultimate event (PE) and antepenultimate event (APE) to be 1.5 ± 0.2 and 2.7 ± 0.4 m, respectively. The APE slip was twice that of the PE slip and 2.5 times larger than the most recent event, the Nagano-ken-hokubu earthquake, and measured 1.2 ± 0.1 m. This suggests that the APE ruptured along the entire length of the 26 km-long Kamishiro Fault or that there were multiple faults involving adjacent segments. As we are unsure how many earthquakes had occurred since the oldest terrace was formed, we assumed three cases based on available paleoseismic records. In each case, we calculated the slip that could reproduce the cumulative slips within a reasonable range of observed terrace offsets and then estimated the coefficient of variation for coseismic slips (COVs) of paleoearthquakes. The resulting COVs typically fell into the range of 0.3 to 0.5, indicating that, over the last few thousand years, the Kamishiro Fault did not regularly behave as it had done before the 2014 event. Instead, there were large variations in the fault’s coseismic slip, as suggested by the global dataset. Although we acknowledge that our approach may be oversimplified, the Monte Carlo-based approach should help assess the regularity of earthquakes from displaced terraces where limited data are available.

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Section: Cumulative Dip Slip Of Mapped Terracesmentioning

confidence: 97%

Section: Inter-event Variability In Coseismic Slip At Oidementioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 98%

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Evaluating variability in coseismic slips of paleo-earthquakes using a flight of displaced terraces across the Kamishiro fault, Itoigawa-Shizuoka Tectonic Line, central Japan

Takahashi

Toda

2020

Preprint

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“…4b), suggesting that more than half of the actual vertical displacement took place off the fault trace. Crustal displacements derived from geodetic methods such as optical correlation of aerial photographs (e.g., Milliner et al 2015) and differential lidar (e.g., Ishimura et al 2019) usually indicate the total slip on the underlying seismogenic fault, including displacement accommodated by flexure, splay faulting, and tapering, and InSAR analysis is no exception (Scott et al 2019). Therefore, our field measurements of the rupture are not considered to be anomalous.…”

Section: Coseismic Surface Ruptures Of the 2011 And 2016 Eventsmentioning

confidence: 99%

Surface rupture and characteristics of a fault associated with the 2011 and 2016 earthquakes in the southern Abukuma Mountains, northeastern Japan, triggered by the Tohoku-Oki earthquake

Komura

Aiyama

Nagata

et al. 2019

Earth Planets Space

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The 2011 Tohoku-Oki offshore subduction earthquake (M w 9.0) triggered many normal-type earthquakes inland in northeastern Japan. Among these were two very similar normal-faulting earthquakes in 2011 (M w 5.8) and 2016 (M w 5.9), which created surface ruptures along the newly named Mochiyama fault within the southern Abukuma Mountains, northeastern Japan, where no active faults had been previously mapped by interpretation of aerial photographs. We conducted field surveys in this area immediately after both earthquakes, and we performed trench excavations and observations of fault fracture zones after the 2016 event. These activities were complemented by an interferometric synthetic aperture radar analysis that mapped the areas of deformation and locations of surface discontinuities for both events. The combined results document the coseismic behavior of the Mochiyama fault during both events. Subtle tectonic geomorphic features associated with the fault were evident in a lidar digital elevation model of the area, and layered structures of gouge were documented in the field. These lines of evidence indicate repeated activity at shallow crustal levels and the possibility of Quaternary activity. In addition, our trench excavations revealed at least one faulting event before 2011. Our comparison of paleoseismic records on this and two other normal faults in the Abukuma Mountains suggests that great earthquakes in the Japan Trench supercycle of 500-700 years do not consistently trigger ruptures on these faults, and the case of 2011, in which the Tohoku-Oki megathrust earthquake triggered all three faults, is a rare occurrence.

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Quantitative assessment of earthquake-induced building damage at regional scale using LiDAR data

Foroughnia,

Macchiarulo,

Berg

et al. 2024

International Journal of Disaster Risk Reduction

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3D Surface Displacement and Surface Ruptures Associated with the 2014 Mw 6.2 Nagano Earthquake Using Differential Lidar

Cited by 14 publications

References 37 publications

Evaluating variability in coseismic slips of paleo-earthquakes using a flight of displaced terraces across the Kamishiro fault, Itoigawa-Shizuoka Tectonic Line, central Japan

Evaluating variability in coseismic slips of paleo-earthquakes using a flight of displaced terraces across the Kamishiro fault, Itoigawa-Shizuoka Tectonic Line, central Japan

Surface rupture and characteristics of a fault associated with the 2011 and 2016 earthquakes in the southern Abukuma Mountains, northeastern Japan, triggered by the Tohoku-Oki earthquake

Quantitative assessment of earthquake-induced building damage at regional scale using LiDAR data

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