scholarly journals Application for source parameters calculations as input for static stress changes studies

2007 ◽  
Vol 40 (4) ◽  
pp. 2008
Author(s):  
P. M. Paradisopoulou ◽  
E. E. Papadimitriou ◽  
V. G. Karakostas ◽  
A. Kilias
Keyword(s):  
Scaling Laws ◽  
Source Parameters ◽  
Active Faults ◽  
Static Stress ◽  
Coulomb Stress ◽  
Coseismic Slip ◽  
Earthquake Source Parameters ◽  
Fault Parameters ◽  
Stress Changes ◽  
Stress Application

The study of static Coulomb Stress changes requires initially the collection of information on the major active faults in a study area concerning their geometry and kinematic properties and then a series of complex calculation for stress changes that are associated with both coseismic displacements of the stronger events and the tectonic loading on these major faults. The Coulomb Stress Application has been developed as a tool to provide a user-friendly way of entering the necessary data and an efficient way to perform the complex calculations procedure. More specifically the aim of the application is a) the collection of data (catalogues of earthquakes, fault parameters) in a relational database, b) the calculation of earthquake source parameters such as the length and the width of the causative fault, and the coseismic slip by using available scaling laws, and finally, c) the execution of all the necessary programs and scripts (e.g. dis3dop.exe, GMT package) to get a map of static stress changes for an area. Coulomb Stress application provides a way to store these data for a study area and it is a method to perform a series of calculations by plotting a series of maps and examine the results for a number of cases.

Seismic doublets and a complex seismic sequence controlled by the rotation of the Juan Fernández microplate

2021 ◽  
Author(s):  
Simone Cesca ◽  
Carla Valenzuela Malebrán ◽  
José Ángel López-Comino ◽  
Timothy Davis ◽  
Carlos Tassara ◽  
...  
Keyword(s):  
Source Parameters ◽  
Strike Slip ◽  
Focal Mechanisms ◽  
Joint Analysis ◽  
Seismic Sequence ◽  
Local Data ◽  
Study Region ◽  
Coulomb Stress Changes ◽  
Earthquake Source Parameters ◽  
Stress Changes

<p> A complex seismic sequence took place in 2014 at the Juan Fernández microplate, a small microplate located between Pacific, Nazca and Antarctica plates. Despite the remoteness of the study region and the lack of local data, we were able to resolve earthquake source parameters and to reconstruct the complex seismic sequence, by using modern waveform-based seismological techniques. The sequence started with an exceptional Mw 7.1-6.7 thrust – strike slip earthquake doublet, the first subevent being the largest earthquake ever recorded in the region and one of the few rare thrust earthquakes in a region otherwise characterized by normal faulting and strike slip earthquakes. The joint analysis of seismicity and focal mechanisms suggest the activation of E-W and NE-SW faults or of an internal curved pseudofault, which is formed in response to the microplate rotation, with alternation of thrust and strike-slip earthquakes. Seismicity migrated Northward in its final phase, towards the microplate edge, where a second doublet with uneven focal mechanisms occurred. The sequence rupture kinematics is well explained by Coulomb stress changes imparted by the first subevent. Our analysis show that compressional stresses, which have been mapped at the northern boundary of the microplate, but never accompanied by large thrust earthquakes, can be accommodated by the rare occurrence of large, impulsive, shallow thrust earthquakes, with a considerable tsunamigenic potential.</p>

scholarly journals Earthquake source parameters that display the first digit phenomenon

2015 ◽  
Vol 22 (5) ◽  
pp. 625-632
Author(s):  
P. A. Toledo ◽  
S. R. Riquelme ◽  
J. A. Campos
Keyword(s):  
Seismic Moment ◽  
Waiting Times ◽  
Source Parameters ◽  
Tohoku Earthquake ◽  
Earthquake Source ◽  
Coseismic Slip ◽  
Self Organized ◽  
Earthquake Source Parameters ◽  
Self Organized Criticality

Abstract. We study the main parameters of earthquakes from the perspective of the first digit phenomenon: the nonuniform probability of the lower first digit different from 0 compared to the higher ones. We found that source parameters like coseismic slip distributions at the fault and coseismic inland displacements show first digit anomaly. We also found the tsunami runups measured after the earthquake to display the phenomenon. Other parameters found to obey first digit anomaly are related to the aftershocks: we show that seismic moment liberation and seismic waiting times also display an anomaly. We explain this finding by invoking a self-organized criticality framework. We demonstrate that critically organized automata show the first digit signature and we interpret this as a possible explanation of the behavior of the studied parameters of the Tohoku earthquake.

Multifault complex rupture and afterslip associated with the 2018 Mw 6.4 Hualien earthquake in northeastern Taiwan

2020 ◽  
Vol 224 (1) ◽  
pp. 416-434
Author(s):  
Dezheng Zhao ◽  
Chunyan Qu ◽  
Xinjian Shan ◽  
Roland Bürgmann ◽  
Wenyu Gong ◽  
...  
Keyword(s):  
Main Shock ◽  
Near Field ◽  
Active Faults ◽  
Fault Model ◽  
Body Waves ◽  
Coseismic Deformation ◽  
Coseismic Slip ◽  
Coulomb Stress Changes ◽  
Seismic Displacement ◽  
Stress Changes

SUMMARY We investigate the coseismic and post-seismic deformation due to the 6 February 2018 Mw 6.4 Hualien earthquake to gain improved insights into the fault geometries and complex regional tectonics in this structural transition zone. We generate coseismic deformation fields using ascending and descending Sentinel-1A/B InSAR data and GPS data. Analysis of the aftershocks and InSAR measurements reveal complex multifault rupture during this event. We compare two fault model joint inversions of SAR, GPS and teleseismic body waves data to illuminate the involved seismogenic faults, coseismic slip distributions and rupture processes. Our preferred fault model suggests that both well-known active faults, the dominantly left-lateral Milun and Lingding faults, and previously unrecognized oblique-reverse west-dipping and north-dipping detachment faults, ruptured during this event. The maximum slip of ∼1.6 m occurred on the Milun fault at a depth of ∼2–5 km. We compute post-seismic displacement time series using the persistent scatterer method. The post-seismic range-change fields reveal large surface displacements mainly in the near-field of the Milun fault. Kinematic inversions constrained by cumulative InSAR displacements along two tracks indicate that the afterslip occurred on the Milun and Lingding faults and the west-dipping fault just to the east. The maximum cumulative afterslip of 0.4–0.6 m occurred along the Milun fault within ∼7 months of the main shock. The main shock-induced static Coulomb stress changes may have played an important role in driving the afterslip adjacent to coseismic high-slip zones on the Milun, Lingding and west-dipping faults.

scholarly journals Tectonic Geomorphology and Paleoseismology of the Sharkhai fault: a new source of seismic hazard for Ulaanbaatar (Mongolia)

2021 ◽  
Author(s):  
Abeer Al-Ashkar ◽  
Antoine Schlupp ◽  
Matthieu Ferry ◽  
Ulziibat Munkhuu
Keyword(s):  
Seismic Hazard ◽  
Scaling Laws ◽  
Active Faults ◽  
Seismic Hazard Assessment ◽  
Capital City ◽  
Tectonic Geomorphology ◽  
Time Interval ◽  
Coseismic Slip ◽  
Slip Rates ◽  
Large Earthquakes

Abstract. We present new constraints from tectonic geomorphology and paleoseismology along the newly discovered Sharkhai fault near the capital city of Mongolia. Detailed observations from high resolution Pleiades satellite images and field investigations allowed us to map the fault in detail, describe its geometry and segmentation, characterize its kinematics, and document its recent activity and seismic behavior (cumulative displacements and paleoseismicity). The Sharkhai fault displays a surface length of ~40 km with a slightly arcuate geometry, and a strike ranging from N42° E to N72° E. It affects numerous drainages that show left-lateral cumulative displacements reaching 57 m. Paleoseismic investigations document the faulting and deposition record for the last ~3000 yr and reveal that the penultimate earthquake (PE) occurred between 1515 ± 90 BC and 945 ± 110 BC and the most recent event (MRE) occurred after 860 ± 85 AD. The resulting time interval of 2080 ± 470 years is the first constraint on the Sharkhai fault for large earthquakes. On the basis of our mapping of the surface rupture and the resulting segmentation analysis, we propose two possible scenarios for large earthquakes with likely magnitudes between 6.4 ± 0.2 and 7.1 ± 0.2. Furthermore, we apply scaling laws to infer coseismic slip values and derive preliminary estimates of long-term slip rates between 0.2 ± 0.2 and 1.0 ± 0.5 mm/y. Finally, we propose that these original observations and results from a newly discovered fault should be taken into account for the seismic hazard assessment for the city of Ulaanbaatar and help build a comprehensive model of active faults in that region.

scholarly journals Earthquake source parameters which display first digit phenomenon

2015 ◽  
Vol 2 (3) ◽  
pp. 811-832
Author(s):  
P. A. Toledo ◽  
S. R. Riquelme ◽  
J. A. Campos
Keyword(s):  
Seismic Moment ◽  
Waiting Times ◽  
Source Parameters ◽  
Tohoku Earthquake ◽  
Earthquake Source ◽  
Coseismic Slip ◽  
Self Organized ◽  
Earthquake Source Parameters ◽  
Self Organized Criticality

Abstract. We study main parameters of earthquakes from the perspective of the first digit phenomenon: the nonuniform probability of the lower first digit different from zero compared to the higher ones. We found that source parameters like coseismic slip distributions at the fault and coseismic inland displacements show first digit anomaly. We also found the tsunami runups measured after the earthquake to display the phenomenon. Other parameters found to obey first digit anomaly are related to the aftershocks: we show that seismic moment liberation and seismic waiting times also display an anomaly. We explain this finding by invoking a self-organized criticality frame. We show that critically organized automata show the first digit signature and we interpret this as a possible explanation of the behavior of the studied parameters of the Tohoku earthquake.

scholarly journals Usefulness of Coulomb Static Stress Changes in Earthquake Hazard Studies: An Example from the Lake Van Area, Eastern Turkey

2021 ◽  
Vol 4 (2) ◽  
pp. 33-41
Author(s):  
Murat Utkucu ◽  
Hatice Durmuş
Keyword(s):  
Earthquake Hazard ◽  
Static Stress ◽  
Coulomb Stress ◽  
Lake Area ◽  
Earthquake Rupture ◽  
Lake Van ◽  
Coulomb Stress Changes ◽  
Calculated Stress ◽  
Stress Changes ◽  
Large Earthquakes

It has been globally documented over different tectonic environments that Coulomb static stress changes caused by a mainshock can promote or demote stresses along the neighboring faults and thus triggers or delays following seismicity. In the present study Coulomb stress changes of the earthquakes in the Lake Van area are calculated using available data and the likely source faults. The calculated stress change maps demonstrate that the large earthquakes in the Lake Area are mostly stressed by the preceding earthquakes, suggesting earthquake rupture interactions. It is further suggested that Coulomb stress maps could be used for constraining the likely locations of the future large earthquakes and in the earthquake hazard mitigation studies.

The earthquake arrest zone

2020 ◽  
Vol 224 (1) ◽  
pp. 581-589 ◽  
Author(s):  
Chun-Yu Ke ◽  
Gregory C McLaskey ◽  
David S Kammer
Keyword(s):  
Stress Distribution ◽  
Initial Stress ◽  
Cohesive Zone ◽  
Large Scale ◽  
Static Stress ◽  
Smooth Transition ◽  
Crack Model ◽  
Coseismic Slip ◽  
Stress Changes ◽  
Natural Earthquakes

SUMMARY Earthquake ruptures are generally considered to be cracks that propagate as fracture or frictional slip on pre-existing faults. Crack models have been used to describe the spatial distribution of fault offset and the associated static stress changes along a fault, and have implications for friction evolution and the underlying physics of rupture processes. However, field measurements that could help refine idealized crack models are rare. Here, we describe large-scale laboratory earthquake experiments, where all rupture processes were contained within a 3-m long saw-cut granite fault, and we propose an analytical crack model that fits our measurements. Similar to natural earthquakes, laboratory measurements show coseismic slip that gradually tapers near the rupture tips. Measured stress changes show roughly constant stress drop in the centre of the ruptured region, a maximum stress increase near the rupture tips and a smooth transition in between, in a region we describe as the earthquake arrest zone. The proposed model generalizes the widely used elliptical crack model by adding gradually tapered slip at the ends of the rupture. Different from the cohesive zone described by fracture mechanics, we propose that the transition in stress changes and the corresponding linear taper observed in the earthquake arrest zone are the result of rupture termination conditions primarily controlled by the initial stress distribution. It is the heterogeneous initial stress distribution that controls the arrest of laboratory earthquakes, and the features of static stress changes. We also performed dynamic rupture simulations that confirm how arrest conditions can affect slip taper and static stress changes. If applicable to larger natural earthquakes, this distinction between an earthquake arrest zone (that depends on stress conditions) and a cohesive zone (that depends primarily on strength evolution) has important implications for how seismic observations of earthquake fracture energy should be interpreted.

Static Stress Changes and Triggering Imposed by Wenchuan Earthquake on Lushan M7 Earthquake

2014 ◽  
Vol 597 ◽  
pp. 324-327
Author(s):  
Dong Ning Lei ◽  
Yong Jian Cai ◽  
Heng Li
Keyword(s):  
Wenchuan Earthquake ◽  
Static Stress ◽  
Coulomb Stress ◽  
Stress Increase ◽  
Stress Changes ◽  
Stress Triggering ◽  
Important Field ◽  
Earthquake Event ◽  
Space Stress

Some faults rupture the surface followed by coseismic dislocation, which causes space stress changes and transmits or imposes static stress on or to neighboring faults.The static stress triggering leads to the adjacent fault ruptured in advance, which means a Coulomb stress increase and triggers a new earthquake event. In recent two decades, some studies on stress triggering became important field of seismotectonics. The occurrence of both Wenchuan M8.0 earthquake and Japan M9.0 eathquake have arisen interest of many researchers, and obtained much new result and understanding.

scholarly journals Static stress transfer from the May 20, 2012, M 6.1 Emilia-Romagna (northern Italy) earthquake using a co-seismic slip distribution model

2012 ◽  
Vol 55 (4) ◽  
Author(s):  
Athanassios Ganas ◽  
Zafeiria Roumelioti ◽  
Konstantinos Chousianitis
Keyword(s):  
Stress Transfer ◽  
Northern Italy ◽  
Static Stress ◽  
Distribution Model ◽  
Coulomb Stress ◽  
Coulomb Stress Changes ◽  
Seismic Slip ◽  
Seismological Data ◽  
Stress Changes ◽  
Fixed Orientation

<p>We model the static stress transfer for the May 2012 northern Italy earthquakes, assuming that failure of the crust occurs by shear. This allows the mechanics of the process to be approximated by the Okada (1992) expressions for displacement and strain fields due to a finite rectangular source in an elastic, homogeneous and isotropic half-space. The slip model of the May 20, 2012, earthquake was derived using empirical Green’s functions and a least-squares inversion scheme of source time functions computed from regional broadband seismological data. The derived model is then incorporated into the computation of Coulomb stress change (ΔCFF) to investigate the possibility that the May 20, 2012, M 6.1 event triggered the second earthquake that occurred on May 29, 2012 (M 5.9). We calculate the Coulomb stress changes for both: (a) optimally oriented planes to regional compression; and (b) planes of fixed orientation assuming that E-W striking, south-dipping thrust faults of the May 29, 2012, type of rupture was a candidate for failure. In both cases, we find that the triggering is promoted as the ΔCFF values in the hypocentral area of the May 29, 2012, earthquake are positive (between 0.61-0.74 bar).</p><p> </p>

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