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Neotectonic synthesis of the mediterranean Languedoc region, Southern France
Published in Hans-Peter Rossmanith, Mechanics of Jointed and Faulted Rock, 2018
It is highly probable that some faults generated or activated during the extensional regime could have been reactivated during the later compressional regime if their orientation favored it. For instance, the NE-SW striking Nîmes fault, that moved as a down-to-the-south normal fault during the Miocene extensional regime, may have been reactivated as a left-lateral reverse fault during the present stress field. Paleoseismic trenching performed by a french team across the easternmost segment of this fault at Courthézon, east of the Rhone river, has revealed that this fault has moved as a north-upthrown low-angle reverse fault in the late Pleistocene. Such slip is in perfect agreement with the present N-S maximum horizontal stress proposed for Southern France and other regions of the Northern Mediterranean realm.
Probabilistic Fault Displacement Hazard Analysis (PFDHA) of a Bhairabi tunnel in North East India
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2020
R.L. Chhangte, T. Rahman, A.I. Laskar
Hecker et al (2013) investigated the nature of earthquake-magnitude distributions on faults. They compared the interevent variability of surface displacement at a point on a fault from composite global data set of paleoseismic observations using truncated exponential and characteristic earthquake model. The characteristic earthquake model produces coefficient variation (CV) values consistent with the data (CV~0.5) only if the variability for a given earthquake is small, which indicate that rupture patterns on a fault are stable. The truncated exponential distribution model give higher values of CV than their respective value obtained from empirical constraint.
Probabilistic Fault Displacement Hazard Analysis (PFDHA) of a Bhairabi tunnel in North East India
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2019
R.L. Chhangte, T. Rahman, A.I. Laskar
Hecker et al (2013) investigated the nature of earthquake-magnitude distributions on faults. They compared the interevent variability of surface displacement at a point on a fault from composite global data set of paleoseismic observations using truncated exponential and characteristic earthquake model. The characteristic earthquake model produces coefficient variation (CV) values consistent with the data (CV~0.5) only if the variability for a given earthquake is small, which indicate that rupture patterns on a fault are stable. The truncated exponential distribution model give higher values of CV than their respective value obtained from empirical constraint.
Late Holocene earthquakes on the Papatea Fault and its role in past earthquake cycles, Marlborough, New Zealand
Published in New Zealand Journal of Geology and Geophysics, 2023
Robert M. Langridge, Kate J. Clark, Peter Almond, Stéphane Baize, Andrew Howell, Jesse Kearse, Regine Morgenstern, Kirstin Deuss, Edwin Nissen, Julián García-Mayordomo, Colin Amos
Paleoseismic studies of historical moderate (MW >6) to great (MW >8) magnitude onshore earthquakes provide many insights into the style and scale of surface deformation, both regionally, and on individual faults (e.g. Rockwell et al. 2000, 2009; Barka et al. 2002; Little et al. 2018; Quigley et al. 2010; Rizza et al. 2011; Oskin et al. 2012; Hornblow et al. 2014; Streig et al. 2014). Historical earthquakes and paleoseismic records fill an important gap in the understanding of earthquake cycles, as well as fault slip and fault interactions that span hundreds to thousands of years longer than seismologic or geodetic records (Lienkaemper et al. 2010; Berryman et al. 2012). Paleoseismic records often offer the best means to investigate the timings and scale of deformation in prior earthquakes and co-rupture of faults through time. For seismic hazard purposes, an historical earthquake provides an exact datum and a slip distribution, to benchmark against paleoearthquake ruptures to consider variability in inter-event recurrence (Rizza et al. 2015; Little et al. 2018), single-event displacement, slip rate (Haddon et al. 2016; Nicol et al. 2016a), and of fault interactions through time (Schwartz et al. 2014).
Past large earthquakes on the Alpine Fault: paleoseismological progress and future directions
Published in New Zealand Journal of Geology and Geophysics, 2018
Jamie D. Howarth, Ursula A. Cochran, Robert M. Langridge, Kate Clark, Sean J. Fitzsimons, Kelvin Berryman, Pilar Villamor, Delia T. Strong
Here, we review on-fault, fault-proximal and off-fault paleoseismic data for the Alpine Fault to provide a synthesis of the fault’s late Holocene rupture behaviour and to evaluate the paleoseismic techniques used for reconstructing the timing of past earthquakes. First, because much of the on-fault data exists in institutional reports that are not readily accessible, we provide a detailed review of, and produce contemporary age models for, paleoseismic trench studies along the Alpine Fault. Second, the findings of published fault-adjacent wetland and fault-proximal lake studies are reviewed to produce a summary of past Alpine Fault ruptures. Third, the paleoseismic record derived from on-fault and fault-proximal records is used to examine landscape disturbance-based paleoseismic proxies, such as rockfalls, dune formation and terrace and floodplain stabilisation, that have been widely used to infer the earthquake history of the fault. Finally, we discuss advantages and disadvantages of the different data series and the most pressing future research questions and directions for earthquake geology on the Alpine Fault.
A 6000-year record of surface-rupturing paleoearthquakes on the Wairau Fault, New Zealand
Published in New Zealand Journal of Geology and Geophysics, 2018
The c. 2000 yr event represents the MRE on the central and eastern Wairau Fault (Zachariasen et al. 2006), with the elapsed time since this event exceeding the average recurrence interval (c. 1000 yr, Figure 10B) for the last 6000 yr by a factor of two and approaching the average recurrence interval for the last 18 kyr (i.e. c. 2300 yr using the combined data Barnes and Pondard 2010, and this study). Given the elapsed time since the MRE, it could be argued that the fault is nearing the end of its seismic cycle along the Wairau Valley to Cloudy Bay section (Zachariasen et al. 2006). However, recurrence intervals for the 18 kyr offshore section of the fault (Figure 10A blue curve) are bimodal with one mode at c. 900 yr and a second at c. 2500 yr. The older of the two modes has a long recurrence tail and much of the histogram in this mode represents recurrence intervals greater than the elapsed time since the MRE (dashed line Figure 10A). Therefore, recurrence intervals for events 2–5 are likely to provide a more pessimistic seismic hazard outlook for the Wairau Fault than would be concluded from the 18 kyr sample record. These data highlight the importance of attaining long paleoseismic records (e.g. for the Wairau Fault more than five earthquakes) for quantifying seismic hazard as accurately as possible.