Evaluating variability in coseismic slips of paleo-earthquakes from an incomplete slip history: an example from displaced terrace flights across the Kamishiro fault, central Japan

AbstractExamining the regularity in slip over seismic cycles leads to an understanding of earthquake recurrence and provides the basis for probabilistic seismic hazard assessment. Systematic analysis of three-dimensional paleoseismic trenches and analysis of offset markers along faults reveal slip history. Flights of displaced terraces have also been used to study slips of paleoearthquakes when the number of earthquakes contributing to the observed displacement of a terrace is known. This study presents a Monte Carlo-based approach to estimating slip variability using displaced terraces when a detailed paleoseismic record is not available. First, we mapped fluvial terraces across the Kamishiro fault, which is an intra-plate reverse fault in central Japan, and systematically measured the cumulative dip slip of the mapped terraces. By combining these measurements with the age of the paleoearthquakes, we estimated the amount of dip slip for the penultimate event (PE) and antepenultimate event (APE) to be 1.6 and 3.4 m, respectively. The APE slip was nearly three times larger than the most recent event of 2014 (Mw 6.2): 1.2 m. This suggests that the rupture length of the APE was much longer than that of the 2014 event and the entire Kamishiro fault ruptured with adjacent faults during the APE. Thereafter, we performed the Monte Carlo simulations to explore the possible range of the coefficient of variation for slip per event (COVs). The simulation considered all the possible rupture histories in terms of the number of events and their slip amounts. The resulting COVs typically ranged between 0.3 and 0.54, indicating a large variation in the slip per event of the Kamishiro fault during the last few thousand years. To test the accuracy of our approach, we performed the same simulation to a fault whose slip per event was well constrained. The result showed that the error in the COVs estimate was less than 0.15 in 86% of realizations, which was comparable to the uncertainty in COVs derived from a paleoseismic trenching. Based on the accuracy test, we conclude that the Monte Carlo-based approach should help assess the regularity of earthquakes using an incomplete paleoseismic record.

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Evaluating variability in coseismic slips of paleo-earthquakes from an incomplete slip history: an example from displaced terrace flights across the Kamishiro fault, central Japan

10.21203/rs.3.rs-25973/v2 ◽

2020 ◽

Author(s):

Naoya Takahashi ◽

Shinji Toda

Keyword(s):

Monte Carlo ◽

Three Dimensional ◽

Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard Assessment ◽

Reverse Fault ◽

Central Japan ◽

Systematic Analysis ◽

Fluvial Terraces ◽

Rupture Length ◽

Slip History

Abstract Examining the regularity in slip over seismic cycles leads to an understanding of earthquake recurrence and provides the basis for probabilistic seismic hazard assessment. Systematic analysis of three-dimensional paleoseismic trenches and analysis of offset markers along faults reveal slip history. Flights of displaced terraces have also been used to study slips of paleoearthquakes when the number of earthquakes contributing to the observed displacement of a terrace is known. This study presents a Monte Carlo-based approach to estimating slip variability using displaced terraces when a detailed paleoseismic record is not available. First, we mapped fluvial terraces across the Kamishiro fault, which is an intra-plate reverse fault in central Japan, and systematically measured the cumulative dip slip of the mapped terraces. By combining these measurements with the age of the paleoearthquakes, we estimated the amount of dip slip for the penultimate event (PE) and antepenultimate event (APE) to be 1.6 and 3.4 m, respectively. The APE slip was nearly three times larger than the most recent event of 2014 (Mw 6.2): 1.2 m. This suggests that the rupture length of the APE was much longer than that of the 2014 event and the entire Kamishiro fault ruptured with adjacent faults during the APE. Thereafter, we performed the Monte Carlo simulations to explore the possible range of the coefficient of variation for slip per event (COVs). The simulation considered all the possible rupture histories in terms of the number of events and their slip amounts. The resulting COVs typically ranged between 0.3 and 0.54, indicating a large variation in the slip per event of the Kamishiro fault during the last few thousand years. To test the accuracy of our approach, we performed the same simulation to a fault whose slip per event was well constrained. The result showed that the error in the COVs estimate was less than 0.15 in 86 % of realizations, which was comparable to the uncertainty in COVs derived from a paleoseismic trenching. Based on the accuracy test, we conclude that the Monte Carlo-based approach should help assess the regularity of earthquakes using an incomplete paleoseismic record.

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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

10.21203/rs.3.rs-25973/v1 ◽

2020 ◽

Author(s):

Naoya Takahashi ◽

Shinji Toda

Keyword(s):

Monte Carlo ◽

Three Dimensional ◽

Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard Assessment ◽

Reverse Fault ◽

Coseismic Slip ◽

Central Japan ◽

Systematic Analysis ◽

Multiple Faults ◽

Fluvial Terraces

Abstract 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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The use of Monte Carlo simulations for seismic hazard assessment in the U.K.

Annals of Geophysics ◽

10.4401/ag-3617 ◽

2000 ◽

Vol 43 (1) ◽

Author(s):

R. M. W. Musson

Keyword(s):

Monte Carlo ◽

Seismic Hazard ◽

Hazard Assessment ◽

Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard Assessment ◽

Logic Tree ◽

The United Kingdom ◽

The Monte Carlo Method ◽

Moderate Seismicity ◽

Seismicity Model

The input required for a seismic hazard study using conventional Probabilistic Seismic Hazard assessment (PSHA) methods can also be used for probabilistic analysis of hazard using Monte Carlo simulation methods. This technique is very flexible, and seems to be under-represented in the literature. It is very easy to modify the form of the seismicity model used, for example, to introduce non-Poissonian behaviour, without extensive reprogramming. Uncertainty in input parameters can also be modelled very flexibly - for example, by the use of a standard deviation rather than by the discrete branches of a logic tree. In addition (and this advantage is perhaps not as trivial as it may sound) the simplicity of the method means that its principles can be grasped by the layman, which is useful when results have to be explained to people outside the seismological/engineering communities, such as planners and politicians. In this paper, some examples of the Monte Carlo method in action are shown in the context of a low to moderate seismicity area: the United Kingdom.

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Preliminary probabilistic seismic hazard assessment for the Kingdom of Saudi Arabia based on combined areal source model: Monte Carlo approach and sensitivity analyses

Soil Dynamics and Earthquake Engineering ◽

10.1016/j.soildyn.2015.06.011 ◽

2015 ◽

Vol 77 ◽

pp. 453-468 ◽

Cited By ~ 15

Author(s):

Hani Mahmoud Zahran ◽

Vladimir Sokolov ◽

Salah El-Hadidiy Youssef ◽

Wael Wassel Alraddadi

Keyword(s):

Monte Carlo ◽

Saudi Arabia ◽

Seismic Hazard ◽

Hazard Assessment ◽

Seismic Hazard Assessment ◽

Source Model ◽

Sensitivity Analyses ◽

Probabilistic Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard ◽

Kingdom Of Saudi Arabia

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A seismicity revision and a probabilistic seismic hazard assessment using the Monte Carlo approach for the Canary Islands (Spain)

Natural Hazards ◽

10.1007/s11069-021-04747-0 ◽

2021 ◽

Author(s):

Julio Mezcua ◽

Juan Rueda

Keyword(s):

Monte Carlo ◽

Seismic Hazard ◽

Canary Islands ◽

Hazard Assessment ◽

Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard ◽

Monte Carlo Approach

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Comparing the best-estimate uniform hazard response spectra to the observed data from the Mw 7.3 earthquake on November 12, 2017 in the Kermanshah areas of western Iran

10.34154/2019-ejgs-0101-19-34/euraass ◽

2019 ◽

pp. 19-34

Author(s):

Nadereh Amerian ◽

Elham Shabani ◽

Ramin Nikrouz

Keyword(s):

Seismic Hazard ◽

Three Dimensional ◽

Seismic Hazard Assessment ◽

Response Spectra ◽

Motion Prediction ◽

Probabilistic Seismic Hazard Assessment ◽

Ground Motion Prediction Equations ◽

Ground Motion Prediction ◽

Hazard Zoning ◽

Hazard Response

In this study, synthetic catalogs based on the Monte Carlo simulations have been produced for probabilistic seismic hazard assessment (PSHA), in the Kermanshah region, West of Iran. Resultant seismic hazard zoning maps, hazard curves and three-dimensional deaggregation of seismic hazard are provided. In order to validate the estimated peak ground accelerations (PGAs), the deduced uniform hazard response spectra (UHRS) are compared with the recorded PGAs in some stations near to the large Mw 7.3 earthquake occurred in the western part of Iran near to Iraq border on 12 November 2017. Different ground motion prediction equations are tested and the results are compared.

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