scholarly journals Nowcasting Earthquakes in Sulawesi Island, Indonesia

2020 ◽  
Author(s):  
Sumanta Pasari ◽  
Andrean VH Simanjuntak ◽  
Yogendra Sharma
Keyword(s):  
Large Earthquake ◽  
Earthquake Hazard ◽  
Earthquake Hazards ◽  
Power Law Distribution ◽  
Probability Models ◽  
Current State ◽  
Natural Time ◽  
Earthquake Hazard Assessment ◽  
Assessment Techniques ◽  
Earthquake Cycles

Abstract Large devastating events such as earthquakes often display frequency-magnitude statistics that exhibit power-law distribution. In this study, we implement a new method of nowcasting (Rundle et al. 2016) to evaluate the current state of earthquake hazards in the seismic prone Sulawesi province, Indonesia. The nowcasting technique considers statistical behavior of small event counts, known as natural times, to infer the seismic progression of large earthquake cycles in a defined region. To develop natural time statistics in the Sulawesi Island, we employ four probability models, namely exponential, exponentiated exponential, gamma, and Weibull distribution. Statistical inference of natural times reveals that (i) exponential distribution has the best representation to the observed data; (ii) estimated nowcast scores (%) corresponding to M≥6.5 events for 21 cities are Bau-bau (41), Bitung (70), Bone (44), Buton (39), Donggala (63), Gorontalo (49), Kendari (27), Kolaka (30), Luwuk (56), Makassar (52), Mamuju (58), Manado (70), Morowali (37), Palopo (34), Palu (62), Pare-pare (82), Polewali (61), Poso (42), Taliabu (55), Toli-toli (58), and Watampone (55); and (iii) the results are broadly consistent to the changes of magnitude threshold and area of local regions. Therefore, the present nowcasting analysis, similar to the traditional earthquake hazard assessment techniques, offers a simple yet versatile metric to the scientists, engineers and policymakers to examine the current state of earthquake hazards in the thickly populated Sulawesi Island.

scholarly journals Nowcasting earthquakes in Sulawesi Island, Indonesia

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sumanta Pasari ◽  
Andrean V. H. Simanjuntak ◽  
Neha ◽  
Yogendra Sharma
Keyword(s):  
Seismic Risk ◽  
Large Earthquake ◽  
Earthquake Hazards ◽  
Power Law Distribution ◽  
Probability Models ◽  
Current State ◽  
City Regions ◽  
Natural Time ◽  
Earthquake Potential ◽  
The City

AbstractLarge devastating events such as earthquakes often display frequency–magnitude statistics that exhibit power-law distribution. In this study, we implement a recently developed method called earthquake nowcasting (Rundle et al. in Earth Space Sci 3: 480–486, 2016) to evaluate the current state of earthquake hazards in the seismic prone Sulawesi province, Indonesia. The nowcasting technique considers statistical behavior of small event counts between successive large earthquakes, known as natural times, to infer the seismic progression of large earthquake cycles in a defined region. To develop natural-time statistics in the Sulawesi Island, we employ four probability models, namely exponential, exponentiated exponential, gamma, and Weibull distribution. Statistical inference of natural times reveals that (i) exponential distribution has the best representation to the observed data; (ii) estimated nowcast scores (%) corresponding to M ≥ 6.5 events for 21 cities are Bau-bau (41), Bitung (70), Bone (44), Buton (39), Donggala (63), Gorontalo (49), Kendari (27), Kolaka (30), Luwuk (56), Makassar (52), Mamuju (58), Manado (70), Morowali (37), Palopo (34), Palu (62), Pare-pare (82), Polewali (61), Poso (42), Taliabu (55), Toli-toli (58), and Watampone (55); and (iii) the results are broadly stable against the changes of magnitude threshold and area of local regions. The presently revealed stationary Poissonian nature of the underlying natural-time statistics in Sulawesi brings out a key conclusion that the seismic risk is the same for all city regions despite their different levels of cycle progression realized through nowcast scores. In addition, though the earthquake potential scores of the city regions will be updated with the occurrence of each small earthquake in the respective region, the seismic risk remains the same throughout the Sulawesi Island.

scholarly journals Complex rupture dynamics on an immature fault during the 2020 Mw 6.8 Elazığ earthquake, Turkey

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
František Gallovič ◽  
Jiří Zahradník ◽  
Vladimír Plicka ◽  
Efthimios Sokos ◽  
Christos Evangelidis ◽  
...  
Keyword(s):  
Stress Transfer ◽  
Strong Motion ◽  
Large Earthquake ◽  
Earthquake Hazard ◽  
Earthquake Hazards ◽  
Earthquake Physics ◽  
Rupture Dynamics ◽  
Earthquake Hazard Assessment ◽  
Modern Physics ◽  
Physical Laws

Abstract Physical laws governing friction on shallow faults in the Earth and spatial heterogeneity of parameters are critical to our understanding of earthquake physics and the assessment of earthquake hazards. Here we use a laboratory-derived fault-friction law and high-quality strong-motion seismic recordings of the 2020 Elazığ earthquake, Turkey, to reveal the complex rupture dynamics. We discover an initial Mw 5.8 rupture stage and explain how cascading behavior of the event, involving at least three episodes, each of M > 6, caused it to evolve into a large earthquake, contrarily to other M5+ events on this part of the East Anatolian Fault. Although the dynamic stress transfer during the rupture did not overcome the strength of the uppermost ~5 kilometers, surface ruptures during future earthquakes cannot be ruled out. We foresee that future, routine dynamic inversions will improve understanding of earthquake rupture parameters, an essential component of modern, physics-based earthquake hazard assessment.

Criteria for Surface Rupture Microzonation of Active Faults for Earthquake Hazards in Urban Areas

2018 ◽  
pp. 187-230
Author(s):  
Hasan Sözbilir ◽  
Çağlar Özkaymak ◽  
Bora Uzel ◽  
Ökmen Sümer
Keyword(s):  
Land Use Planning ◽  
Urban Areas ◽  
Active Faults ◽  
Earthquake Hazard ◽  
Disaster Mitigation ◽  
Rupture Zone ◽  
Earthquake Hazards ◽  
Surface Rupture ◽  
Earthquake Hazard Assessment ◽  
Earthquake Effects

Formation of surface rupture zone along active faults buried directly beneath major cities create devastating earthquakes that seriously threaten the safety of human lives. Surface rupture microzonation (SRM) is the generic name for subdividing a region into individual areas having different potentials hazardous earthquake effects, defining their specific seismic behavior for engineering design and land-use planning in case a large devastating earthquake strikes the region. The basis of SRM is to model the rupture zone at the epicenter of an earthquake, and thus develop a hazard-avoid map indicating the vulnerability of the area to potential seismic hazard. Earthquake hazard assessment of active faults in urban areas are thus an important systematic engineering for disaster mitigation in major cities.

Estimation of fault propagation distance from fold shape: Implications for earthquake hazard assessment

Geology ◽  
2000 ◽  
Vol 28 (12) ◽  
pp. 1099-1102 ◽  
Author(s):  
Richard W. Allmendinger ◽  
John H. Shaw
Keyword(s):  
Hazard Assessment ◽  
Earthquake Hazard ◽  
Propagation Distance ◽  
Fault Propagation ◽  
Earthquake Hazard Assessment

Deformation and displacement fields of the Himalayan arc, seismicity and large earthquake hazards in its eastern segment and vicinity

1987 ◽  
Vol 138 (1) ◽  
pp. 93-107 ◽  
Author(s):  
Wei Luo ◽  
Nengqian Jiang ◽  
Zhuoli Luo
Keyword(s):  
Large Earthquake ◽  
Earthquake Hazards ◽  
Displacement Fields ◽  
Eastern Segment

scholarly journals U–Pb dating of middle Eocene–Pliocene multiple tectonic pulses in the Alpine foreland

Solid Earth ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 2539-2551
Author(s):  
Luca Smeraglia ◽  
Nathan Looser ◽  
Olivier Fabbri ◽  
Flavien Choulet ◽  
Marcel Guillong ◽  
...  
Keyword(s):  
Middle Eocene ◽  
Regional Scale ◽  
Earthquake Hazard ◽  
Late Eocene ◽  
Passive Margin ◽  
Tectonic Activity ◽  
Thrust Belt ◽  
Fold And Thrust Belt ◽  
Earthquake Hazard Assessment ◽  
Alpine Foreland

Abstract. Foreland fold-and-thrust belts (FTBs) record long-lived tectono-sedimentary activity, from passive margin sedimentation, flexuring, and further evolution into wedge accretion ahead of an advancing orogen. Therefore, dating fault activity is fundamental for plate movement reconstruction, resource exploration, and earthquake hazard assessment. Here, we report U–Pb ages of syn-tectonic calcite mineralizations from four thrusts and three tear faults sampled at the regional scale across the Jura fold-and-thrust belt in the northwestern Alpine foreland (eastern France). Three regional tectonic phases are recognized in the middle Eocene–Pliocene interval: (1) pre-orogenic faulting at 48.4±1.5 and 44.7±2.6 Ma associated with the far-field effect of the Alpine or Pyrenean compression, (2) syn-orogenic thrusting at 11.4±1.1, 10.6±0.5, 9.7±1.4, 9.6±0.3, and 7.5±1.1 Ma associated with the formation of the Jura fold-and-thrust belt with possible in-sequence thrust propagation, and (3) syn-orogenic tear faulting at 10.5±0.4, 9.1±6.5, 5.7±4.7, and at 4.8±1.7 Ma including the reactivation of a pre-orogenic fault at 3.9±2.9 Ma. Previously unknown faulting events at 48.4±1.5 and 44.7±2.6 Ma predate the reported late Eocene age for tectonic activity onset in the Alpine foreland by ∼10 Myr. In addition, we date the previously inferred reactivation of pre-orogenic strike-slip faults as tear faults during Jura imbrication. The U–Pb ages document a minimal time frame for the evolution of the Jura FTB wedge by possible in-sequence thrust imbrication above the low-friction basal decollement consisting of evaporites.

Earthquake ruptures tied to long-lived plate interface deformation 

2021 ◽  
Author(s):  
Nadaya Cubas ◽  
Philippe Agard ◽  
Roxane Tissandier
Keyword(s):  
Subduction Zones ◽  
Earthquake Hazard ◽  
Mechanical Analysis ◽  
Physical Parameters ◽  
Plate Interface ◽  
Interface Deformation ◽  
Earthquake Hazard Assessment ◽  
Interseismic Coupling ◽  
Rate And State Friction

<p>Predicting the spatial extent of mega-earthquakes is an essential ingredient of earthquake hazard assessment. In subduction zones, this prediction mostly relies on geodetic observations of interseismic coupling. However, such models face spatial resolution issues and are of little help to predict full or partial ruptures of highly locked patches. Coupling models are interpreted in the framework of the rate-and-state friction laws. However, these models are too idealized to take into account the effects of a geometrically or rheologically complex plate interface. In this study, we show, from the critical taper theory and a mechanical analysis of the topography, that all recent mega-earthquakes of the Chilean subduction zone are surrounded by distributed interplate deformation emanating from either underplating or basal erosion. This long-lived plate interface deformation builds up stresses ultimately leading to earthquake nucleation. Earthquakes then propagate along a relatively smooth surface and are stopped by segments of heterogeneously distributed deformation. Our results are consistent with long-term features of the subduction margin, with observed short-term deformation as well as physical parameters of recovered subducted fragments. They also provide an explanation for the apparent mechanical segmentation of the megathrust, reconciling many seemingly contradictory observations on the short- and long-term deformation. Consequently, we propose that earthquake segmentation relates to the distribution of deformation along the plate interface and that slip deficit patterns reflect the along-dip and along-strike distribution of the plate interface deformation. Topography would therefore mirror plate interface deformation and could serve to improve earthquake rupture prediction.</p>

Contemporary deformation and earthquake hazard of the Capital Circle of China inferred from GPS Measurements

2021 ◽  
Author(s):  
Shaogang Wei ◽  
Xiwei Xu ◽  
Tuo Shen ◽  
Xiaoqiong Lei
Keyword(s):  
High Risk ◽  
Earthquake Hazard ◽  
Historical Earthquakes ◽  
Tectonic Stress ◽  
Middle Part ◽  
Earthquake Hazards ◽  
Seismic Belt ◽  
Fault Plane Solutions ◽  
The North ◽  
Recent Earthquakes

<p>The Capital Circle (CC) is a region with high risk of great damaging earthquake hazards. In our present study, by using a subset of rigorously GPS data around the North China Plain (NCP), med-small recent earthquakes data and focal mechanism of high earthquakes data covering its surrounding regions, the following major conclusions have been reached: (a) Driven by the deformation force associated with both eastward and westward motion, with respect to the NCP, of the rigid South China and the rigid Amurian block, widespread sinistral shear appear over the NCP, which results in clusters of parallel NNE-trending faults with predominant right-lateral strike-slips via bookshelf faulting within the interior of the NCP. (b) Fault plane solutions of recent earthquakes show that tectonic stress field in the NCP demonstrate overwhelming NE-ENE direction of the maximum horizontal principal stress, and that almost all great historical earthquakes in the NCP occurred along the NWW-trending Zhangjiakou-Bohai seismic belt and the NNE-trending Tangshan-Hejian-Cixian seismic belt. Additionally, We propose a simple conceptual model for inter-seismic deformation associated with the Capital Circle, which might suggest that two seismic gaps are located on the middle part of Tangshan-Hejian-Cixian fault seismic belt (Tianjin-Hejian segment) and the northeast part of Tanlu seismic belt (Anqiu segment), and constitute as, in our opinion, high risk areas prone to great earthquakes.</p>

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