2017 Mw 8.1 Tehuantepec Earthquake: Deep Slip and Rupture Directivity Enhance Ground Shaking but Weaken the Tsunami

2018 ◽  
Vol 89 (4) ◽  
pp. 1314-1322 ◽  
Author(s):  
Kejie Chen ◽  
Wanpeng Feng ◽  
Zhen Liu ◽  
Y. Tony Song
Keyword(s):  
Rupture Directivity ◽  
Ground Shaking

scholarly journals Effects of finite source rupture on landslide triggering: The 2016 <i>M<sub>W</sub></i> 7.1 Kumamoto earthquake

2018 ◽  
Author(s):  
Sebastian von Specht ◽  
Ugur Ozturk ◽  
Georg Veh ◽  
Fabrice Cotton ◽  
Oliver Korup
Keyword(s):  
Radiation Pattern ◽  
Ground Motion ◽  
Low Frequency ◽  
New Physics ◽  
Rupture Directivity ◽  
Ground Shaking ◽  
Kumamoto Earthquake ◽  
Directivity Effect ◽  
Seismic Rupture ◽  
Landslide Distribution

Abstract. The propagation of a seismic rupture on a fault introduces spatial variations in the seismic wavefield surrounding the fault during an earthquake. This directivity effect results in larger shaking amplitudes in the rupture propagation direction. Its seismic radiation pattern also causes amplitude variations between the strike-normal and strike-parallel components of horizontal ground motion. We investigated the landslide response to these effects during the 2016 Kumamoto earthquake (MW 7.1) in central Kyūshū (Japan). Although the distribution of some 1,500 earthquake-triggered landslides as function of rupture distance is consistent with the observed Arias intensity, the landslides are more concentrated to the northeast of the southwest-northeast striking rupture. We examined several landslide susceptibility factors: hillslope inclination, median amplification factor (MAF) of ground shaking, lithology, land cover, and topographic wetness. None of these factors can sufficiently explain the landslide distribution or orientation (aspect), although the landslide headscarps coincide with elevated hillslope inclination and MAF. We propose a new physics-based ground motion model that accounts for the seismic rupture effects, and demonstrate that the low-frequency seismic radiation pattern consistent with the overall landslide distribution. The spatial landslide distribution is primarily influenced by the rupture directivity effect, whereas landslide aspect is influenced by amplitude variations between the fault-normal and fault-parallel motion at frequencies

scholarly journals Prediction of the area affected by earthquake-induced landsliding based on seismological parameters

2017 ◽  
Vol 17 (7) ◽  
pp. 1159-1175 ◽  
Author(s):  
Odin Marc ◽  
Patrick Meunier ◽  
Niels Hovius
Keyword(s):  
Scaling Laws ◽  
Seismic Energy ◽  
Seismic Source ◽  
Distribution Area ◽  
Rupture Directivity ◽  
Source Depth ◽  
Landslide Area ◽  
Earthquake Parameters ◽  
Ground Shaking ◽  
Landslide Distribution

Abstract. We present an analytical, seismologically consistent expression for the surface area of the region within which most landslides triggered by an earthquake are located (landslide distribution area). This expression is based on scaling laws relating seismic moment, source depth, and focal mechanism with ground shaking and fault rupture length and assumes a globally constant threshold of acceleration for onset of systematic mass wasting. The seismological assumptions are identical to those recently used to propose a seismologically consistent expression for the total volume and area of landslides triggered by an earthquake. To test the accuracy of the model we gathered geophysical information and estimates of the landslide distribution area for 83 earthquakes. To reduce uncertainties and inconsistencies in the estimation of the landslide distribution area, we propose an objective definition based on the shortest distance from the seismic wave emission line containing 95 % of the total landslide area. Without any empirical calibration the model explains 56 % of the variance in our dataset, and predicts 35 to 49 out of 83 cases within a factor of 2, depending on how we account for uncertainties on the seismic source depth. For most cases with comprehensive landslide inventories we show that our prediction compares well with the smallest region around the fault containing 95 % of the total landslide area. Aspects ignored by the model that could explain the residuals include local variations of the threshold of acceleration and processes modulating the surface ground shaking, such as the distribution of seismic energy release on the fault plane, the dynamic stress drop, and rupture directivity. Nevertheless, its simplicity and first-order accuracy suggest that the model can yield plausible and useful estimates of the landslide distribution area in near-real time, with earthquake parameters issued by standard detection routines.

scholarly journals Prediction of the area affected by earthquake-induced landsliding based on seismological parameters

2017 ◽  
Author(s):  
Odin Marc ◽  
Patrick Meunier ◽  
Niels Hovius
Keyword(s):  
Scaling Laws ◽  
Distribution Area ◽  
Rupture Directivity ◽  
Source Depth ◽  
Landslide Area ◽  
Earthquake Parameters ◽  
Critical Acceleration ◽  
Ground Shaking ◽  
Landslide Volume ◽  
Landslide Distribution

Abstract. We present an analytical, seismologically consistent expression for the surface area of the region within which landslides induced by a given earthquake are distributed. The expression is based on scaling laws relating seismic moment, source depth and focal mechanism with ground shaking and fault rupture length and assumes a globally constant critical acceleration for onset of systematic mass wasting. The seismological assumptions are identical to those recently used to propose a seismologically consistent expression for total landslide volume and area. To test the accuracy of the model we gathered geophysical information and estimates of the landslide distribution area for 83 earthquakes. To reduce uncertainties and inconsistencies in the estimation of the landslide distribution area, we propose an objective definition based on the shortest distance from the seimsic wave emission line containing 95 % of the total landslide area. Without any empirical calibration the model explains 56 % of the variance in our dataset, and predicts 35 to 49 out of 83 cases within a factor two, depending on how we account for uncertainties on the seismic source depth. For most cases with comprehensive landslide inventories we show that our prediction compares well with the smallest region around the fault containing 95 % of the total landslide area. Aspects ignored by the model that could explain the residuals include, local variations of the critical acceleration and processes modulating the surface ground shaking, such as the distribution of seismic energy release on the fault plane, the dynamic stress drop or the rupture directivity. Nevertheless, its simplicity and first order accuracy suggest that the model can yield plausible and useful estimates of the landslide distribution area in near-real time, with earthquake parameters issued by standard detection routines.

scholarly journals Effects of finite source rupture on landslide triggering: the 2016 <i>M</i><sub>w</sub> 7.1 Kumamoto earthquake

Solid Earth ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 463-486 ◽  
Author(s):  
Sebastian von Specht ◽  
Ugur Ozturk ◽  
Georg Veh ◽  
Fabrice Cotton ◽  
Oliver Korup
Keyword(s):  
Radiation Pattern ◽  
Ground Motion ◽  
Low Frequency ◽  
New Physics ◽  
Rupture Directivity ◽  
Ground Shaking ◽  
Kumamoto Earthquake ◽  
Directivity Effect ◽  
Seismic Rupture ◽  
Landslide Distribution

Abstract. The propagation of a seismic rupture on a fault introduces spatial variations in the seismic wave field surrounding the fault. This directivity effect results in larger shaking amplitudes in the rupture propagation direction. Its seismic radiation pattern also causes amplitude variations between the strike-normal and strike-parallel components of horizontal ground motion. We investigated the landslide response to these effects during the 2016 Kumamoto earthquake (Mw 7.1) in central Kyushu (Japan). Although the distribution of some 1500 earthquake-triggered landslides as a function of rupture distance is consistent with the observed Arias intensity, the landslides were more concentrated to the northeast of the southwest–northeast striking rupture. We examined several landslide susceptibility factors: hillslope inclination, the median amplification factor (MAF) of ground shaking, lithology, land cover, and topographic wetness. None of these factors sufficiently explains the landslide distribution or orientation (aspect), although the landslide head scarps have an elevated hillslope inclination and MAF. We propose a new physics-based ground-motion model (GMM) that accounts for the seismic rupture effects, and we demonstrate that the low-frequency seismic radiation pattern is consistent with the overall landslide distribution. Its spatial pattern is influenced by the rupture directivity effect, whereas landslide aspect is influenced by amplitude variations between the fault-normal and fault-parallel motion at frequencies <2 Hz. This azimuth dependence implies that comparable landslide concentrations can occur at different distances from the rupture. This quantitative link between the prevalent landslide aspect and the low-frequency seismic radiation pattern can improve coseismic landslide hazard assessment.

scholarly journals The ShakeMaps of the Amatrice, M6, earthquake

2016 ◽  
Vol 59 ◽  
Author(s):  
Licia Faenza ◽  
Valentino Lauciani ◽  
Alberto Michelini
Keyword(s):  
Ground Motion ◽  
Data Exchange ◽  
Main Shock ◽  
Central Italy ◽  
Strong Motion ◽  
Rupture Directivity ◽  
Time Data ◽  
Epicentral Area ◽  
Ground Shaking ◽  
Motion Data

In this paper we describe the performance of the ShakeMap software package and the fully automatic procedure, based on manually revised location and magnitude, during the main event of the Amatrice sequence with special emphasis to the M6 main shock, that struck central Italy on the 24th August 2016 at 1:36:32 UTC. Our results show that the procedure we developed in the last years, with real-time data exchange among those institutions acquiring strong motion data, allows to provide a faithful description of the ground motion experienced throughout a large region in and around the epicentral  area. The prompt availability of the rupture fault model, within three hours after the earthquake occurrence, provided a better descriptions of the level of strong ground motion throughout the affected area.  Progressive addition of  station data and  manual verification of the data insures improvements in the description of the experienced ground motions.  In particular, comparison between the MCS intensity shakemaps and preliminary field macroseismic reports show favourable similarities.  Finally the overall  spatial pattern of the ground motion of the main shock is consistent with reported rupture directivity toward NW and reduced levels of ground shaking toward SW probably linked to the peculiar source effects of the earthquake.

scholarly journals Characteristics of the Strong Ground Motion from the 24th August 2016 Amatrice Earthquake

2016 ◽  
Vol 59 ◽  
Author(s):  
Marta Pischiutta ◽  
Aybige Akinci ◽  
Luca Malagnini ◽  
André Herrero
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Normal Fault ◽  
Peak Ground Velocity ◽  
Rupture Directivity ◽  
Ground Acceleration ◽  
Ground Shaking ◽  
North West ◽  
Motion Characteristics ◽  
2016 Amatrice Earthquake

<em>The 2016 August 24 Amatrice earthquake occurred at 03:36 local time in Central Apennines Italy with an epicentre at 43.36<sup>°</sup>E, 38.76<sup>°</sup>N, Istituto Nazionale di Geofisica e Vulcanologia (INGV), few kilometers north of the city of Amatrice. The earthquake ruptured a North-West (NW)–South-East (SE) oriented normal fault dipping toward the South-West (SW) (Scognamiglio et al., 2016). High values of peak ground acceleration (~0.45 g) were observed close to Amatrice (3 stations being few kilometer distances from the fault). The present study presents an overview of the main features of the seismic ground shaking during the Amatrice earthquake. We analyze the ground motion characteristics of the main shock in terms of peak ground acceleration (PGA), peak ground velocity (PGV) and spectral accelerations (SA, 5 per cent of critical damping). In order to understand the characteristics of the ground motions induced by Amatrice earthquake, we also study the source-related effects relative to the fault rupture directivity.</em>

scholarly journals The Alto Tiberina Near Fault Observatory (northern Apennines, Italy)

2014 ◽  
Vol 57 (3) ◽  
Author(s):  
Lauro Chiaraluce ◽  
Alessandro Amato ◽  
Simona Carannante ◽  
Viviana Castelli ◽  
Marco Cattaneo ◽  
...  
Keyword(s):  
Hanging Wall ◽  
Detection Threshold ◽  
Northern Apennines ◽  
Fault System ◽  
Rupture Directivity ◽  
Seismic Stations ◽  
Ground Shaking ◽  
High Resolution Data ◽  
Seismicity Rate ◽  
Near Fault

<p>The availability of multidisciplinary and high-resolution data is a fundamental requirement to understand the physics of earthquakes and faulting. We present the Alto Tiberina Near Fault Observatory (TABOO), a research infrastructure devoted to studying preparatory processes, slow and fast deformation along a fault system located in the upper Tiber Valley (northern Apennines), dominated by a 60 km long low-angle normal fault (Alto Tiberina, ATF) active since the Quaternary. TABOO consists of 50 permanent seismic stations covering an area of 120 × 120 km<span><sup>2</sup></span>. The surface seismic stations are equipped with 3-components seismometers, one third of them hosting accelerometers. We instrumented three shallow (250 m) boreholes with seismometers, creating a 3-dimensional antenna for studying micro-earthquakes sources (detection threshold is M<span><sub>L</sub></span> 0.5) and detecting transient signals. 24 of these sites are equipped with continuous geodetic GPS, forming two transects across the fault system. Geochemical and electromagnetic stations have been also deployed in the study area. In 36 months TABOO recorded 19,422 events with M<span><sub>L</sub></span> ≤ 3.8 corresponding to 23.36e-04 events per day per squared kilometres; one of the highest seismicity rate value observed in Italy. Seismicity distribution images the geometry of the ATF and its antithetic/synthetic structures located in the hanging-wall. TABOO can allow us to understand the seismogenic potential of the ATF and therefore contribute to the seismic hazard assessment of the area. The collected information on the geometry and deformation style of the fault will be used to elaborate ground shaking scenarios adopting diverse slip distributions and rupture directivity models.</p>

scholarly journals Fault source investigation of the 6 December 2016 MwMw 6.5 Pidie Jaya, Indonesia, earthquake based on GPS and its implications of the geological survey result

2020 ◽  
Vol 14 (4) ◽  
pp. 405-412
Author(s):  
Endra Gunawan ◽  
Takuya Nishimura ◽  
Susilo Susilo ◽  
Sri Widiyantoro ◽  
Nanang T. Puspito ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Source Parameters ◽  
Secondary Effects ◽  
Near Surface ◽  
Morphological Attributes ◽  
Ground Shaking ◽  
The North ◽  
Coulomb Failure ◽  
North And South ◽  
Fault Source

AbstractOn 6 December 2016 at 22:03 UTC, a devastating magnitude 6-class strike-slip earthquake occurred along an unidentified and unmapped fault in Pidie Jaya, northern Sumatra. We analysed the possible fault using continuous Global Positioning System (GPS) observation available in the region. In our investigation, we searched for the fault source parameters of the north- and south-dipping left-lateral faults and the west- and east-dipping right-lateral faults. We identified that the fault responsible for the earthquake was located offshore, with a southwest-northeast direction. We also computed the Coulomb failure stress and compared the result with the distribution of the aftershocks. In this study, we demonstrated that the result of the geological field survey conducted soon after the mainshock was attributed to the secondary effects of ground shaking and near-surface deformation, and not surface faulting. The newly identified offshore fault proposed by this study calls for further investigation of the corresponding submarine morphological attributes in this particular region.

scholarly journals Exceedance of design actions in epicentral areas: insights from the ShakeMap envelopes for the 2016–2017 central Italy sequence

2021 ◽  
Author(s):  
Iunio Iervolino ◽  
Pasquale Cito ◽  
Chiara Felicetta ◽  
Giovanni Lanzano ◽  
Antonio Vitale
Keyword(s):  
Earthquake Engineering ◽  
Structural Damage ◽  
Structural Engineering ◽  
Central Italy ◽  
Civil Defense ◽  
Point Of View ◽  
Seismic Sequence ◽  
Ground Shaking ◽  
Motion Effect ◽  
Observed Damage

AbstractShakeMap is the tool to evaluate the ground motion effect of earthquakes in vast areas. It is useful to delimit the zones where the shaking is expected to have been most significant, for civil defense rapid response. From the earthquake engineering point of view, it can be used to infer the seismic actions on the built environment to calibrate vulnerability models or to define the reconstruction policies based on observed damage vs shaking. In the case of long-lasting seismic sequences, it can be useful to develop ShakeMap envelopes, that is, maps of the largest ground intensity among those from the ShakeMap of (selected) events of a seismic sequence, to delimit areas where the effects of the whole sequence have been of structural engineering relevance. This study introduces ShakeMap envelopes and discusses them for the central Italy 2016–2017 seismic sequence. The specific goals of the study are: (i) to compare the envelopes and the ShakeMap of the main events of the sequence to make the case for sequence-based maps; (ii) to quantify the exceedance of design seismic actions based on the envelopes; (iii) to make envelopes available for further studies and the reconstruction planning; (iv) to gather insights on the (repeated) exceedance of design seismic actions at some sites. Results, which include considerations of uncertainty in ShakeMap, show that the sequence caused exceedance of design hazard in thousands of square kilometers. The most relevant effects of the sequence are, as expected, due to the mainshock, yet seismic actions larger than those enforced by the code for structural design are found also around the epicenters of the smaller magnitude events. At some locations, the succession of ground-shaking that has excited structures, provides insights on structural damage accumulation that has likely taken place; something that is not accounted for explicitly in modern seismic design. The envelopes developed are available as supplemental material.

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