scholarly journals INFLUENCE OF STRESS TRANSFER IN PROBABILITY ESTIMATES OF M≥6.5 EARTHQUAKES IN GREECE AND SURROUNDING AREAS

2017 ◽  
Vol 43 (4) ◽  
pp. 2114
Author(s):  
P. M. Paradisopoulou ◽  
E. E. Papadimitriou ◽  
V. G. Karakostas ◽  
S. Lasocki ◽  
J. Mirek ◽  
...  
Keyword(s):  
Stress Transfer ◽  
Transient Effects ◽  
Strong Earthquakes ◽  
Earthquake Probability ◽  
Probability Estimates ◽  
Stress Changes ◽  
Coulomb Failure ◽  
Earthquake Nucleation ◽  
Major Fault ◽  
Surrounding Areas

The coseismic stress changes due to strong earthquakes (M>6.5) that occurred in Greece and its adjacent areas since the beginning of the 20th century (instrumental era) are calculated and the future seismic hazard expressed in terms of the probabilities of occurrence of M≥6.5 events is assessed. Calculations of the change in Coulomb failure stress reveal that 61 out of 67 ruptures were brought closer to failure by the preceding shocks. A new insight on the evaluation of future seismic hazards, in the study area, is given by translating the calculated coseismic stress changes into earthquake probability. We incorporated the effect of stress change into the time–depended probability estimates using an earthquake nucleation constitutive relation, which includes both permanent and transient effects of stress changes. Taking into account the current stress changes onto each major fault, the probability calculations were performed and given for the whole study area during the next 30 years

scholarly journals SIGNIFICANT EARTHQUAKES NEAR THE CITY OF THESSALONIKI (NORTHERN GREECE) AND PROBABILITY DISTRIBUTION ON FAULTS

2017 ◽  
Vol 50 (3) ◽  
pp. 1389
Author(s):  
P.M. Paradisopoulou ◽  
E.E. Papadimitriou ◽  
J. Mirek
Keyword(s):  
Stress Transfer ◽  
Time Dependent ◽  
Earthquake Catalog ◽  
Northern Greece ◽  
Earthquake Probability ◽  
Fault Segment ◽  
Probability Estimates ◽  
Macroseismic Intensities ◽  
The City ◽  
Dependent Probability

Stress triggering must be incorporated into quantitative earthquake probability estimate, given that faults are interacted though their stress field. Using time dependent probability estimates this work aims at the evaluation of the occurrence probability of anticipated earthquakes near the city of Thessaloniki, an urban center of 1 million people located in northern Greece, conditional to the time elapsed since the last stronger event on each fault segment of the study area. A method that calculates the macroseismic epicenter and magnitude according to macroseismic intensities is used to improve the existing earthquake catalog (from AD 1600 - 2013 with M≥6.0) in order to compute new interevent and elapsed time values which form the basis for time-dependent probability estimates. To investigate the effects of stress transfer to seismic hazard, the probabilistic calculations presented here employ detailed models of coseismic stress associated with the 20 June 1978 M=6.5 Thessaloniki which is the latest destructive earthquake in the area in the instrumental era. The combined 2015-2045 regional Poisson probability of M≥6.0 earthquakes is ~35% the regional time-dependent probability varies from 0% to 15% and incorporation of stress transfer from 0% to 20% for each fault segment.

scholarly journals Coseismic stress distribution along active structures and their influence on timedependent probability values.

2016 ◽  
Vol 47 (3) ◽  
pp. 1211
Author(s):  
P. Paradisopoulou ◽  
E. Papadimitriou ◽  
J. Mirek ◽  
V. Karakostas
Keyword(s):  
Occurrence Rate ◽  
Recurrence Time ◽  
Time Interval ◽  
Coseismic Slip ◽  
Coulomb Stress Changes ◽  
Earthquake Probability ◽  
Fault Segment ◽  
Active Structures ◽  
Probability Estimates ◽  
Stress Changes

Based on the fact that stress changes caused by the coseismic slip of strong events can be incorporated into quantitative earthquake probability estimates, the goal of this study is to estimate the probability of the next strong earthquake (M≥6.5) on a known fault segment in a future time interval (30 years). The probability depends on the calculation of ΔCFF and the estimate of the occurrence rate of a characteristic earthquake, conditioned to the elapsed time since the previous event. The Coulomb stress changes caused by previous earthquakes are computed and their influence are considered by the introduction of a permanent shift on the time elapsed since theprevious earthquake or by a modification of the expected mean recurrence time. The occurrence rate is calculated, taking into account both permanent and temporary perturbations. The estimated probability values correspond to the probabilities along each fault segment with discretization of 1km, illustrating the probability distribution across the specific fault. In order to check whether the estimated probability vary with depth, all the estimations were performed for each fault at depths of 8, 10, 12 and 15 km. 

scholarly journals Earthquake static stress transfer in the 2013 Gulf of Valencia (Spain) seismic sequence

Solid Earth ◽  
2017 ◽  
Vol 8 (5) ◽  
pp. 857-882 ◽  
Author(s):  
Lluís Saló ◽  
Tànit Frontera ◽  
Xavier Goula ◽  
Luis G. Pujades ◽  
Alberto Ledesma
Keyword(s):  
Stress Transfer ◽  
Mediterranean Coast ◽  
Static Stress ◽  
Earthquake Triggering ◽  
Underground Gas Storage ◽  
Focal Mechanism Solutions ◽  
Stress Changes ◽  
Coulomb Failure ◽  
As Stress

Abstract. On 24 September 2013, an Ml 3.6 earthquake struck in the Gulf of Valencia (Spain) near the Mediterranean coast of Castelló, roughly 1 week after gas injections conducted in the area to develop underground gas storage had been halted. The event, felt by the nearby population, led to a sequence build-up of felt events which reached a maximum of Ml 4.3 on 2 October.Here, we study the role of static stress transfer as an earthquake-triggering mechanism during the main phase of the sequence, as expressed by the eight felt events. By means of the Coulomb failure function, cumulative static stress changes are quantified on fault planes derived from focal mechanism solutions (which act as both source and receiver faults) and on the previously mapped structures in the area (acting only as stress receivers in our modeling). Results suggest that static stress transfer played a destabilizing role and point towards an SE-dipping structure underlying the reservoir (or various with analogous geometry) that was most likely activated during the sequence. One of the previously mapped faults could be geometrically compatible, yet our study supports deeper sources. Based on this approach, the influence of the main events in the occurrence of future and potentially damaging earthquakes in the area would not be significant.

scholarly journals KAMCHATKA AND COMMANDER ISLANDS

2020 ◽  
pp. 172-182
Author(s):  
D. Chebrov ◽  
A. Chebrova ◽  
I. Abubakirov ◽  
E. Matveenko ◽  
S. Mityushkina ◽  
...  
Keyword(s):  
Moment Tensor ◽  
Seismic Intensity ◽  
Earthquake Catalogue ◽  
Seismic Moment Tensor ◽  
Magnitude Of Completeness ◽  
Commander Islands ◽  
Strong Earthquakes ◽  
Double Couple ◽  
Kamchatka Earthquake ◽  
Surrounding Areas

The seismicity review of Kamchatka and surrounding territories for 2014 is given. In Kamchatka earthquake catalogue minimum local magnitude of completeness is MLmin=3.5, and for earthquakes under the Okhotsk sea with h≥350 kmMLmin=3.6. The Kamchatka earthquake catalogue for 2014 with ML3.5, published in the Appendix to this annual, includes 1114 events. 86 earthquakes of the catalogue with ML=3.35–6.2 were felt in Kamchatka and surrounding areas with seismic intensity I ranged from 2 to 5 according the MSK-64 scale. For all events with ML5.0 occurred in the area of responsibility of the KB GS RAS in 2014, an attempt to calculate the seismic moment tensor (SMT) was made. There are 40 such events in the regional catalogue. For 36 earthquakes, the SMT and depth h of the equivalent point source were calculated successfully. The calcu-lations were performed for the SMT double-couple model using a nonlinear algorithm. In 2014, a typical location of the earthquake epicenters was observed in the Kamchatka zone. In 2014, the seismicity level in all selected zones and in the region as a whole corresponded to the background one according to the “SESL’09” scale. The number of recorded events with ML3.6 and strong earthquakes with ML5.1 is close to the average annual value. Anomalous and outstanding events were not recorded.

A New Technique to Calculate Earthquake Stress Transfer and to Probe the Physics of Aftershocks

2020 ◽  
Vol 110 (2) ◽  
pp. 863-873 ◽  
Author(s):  
Margarita Segou ◽  
Tom Parsons
Keyword(s):  
Stress Reduction ◽  
Regional Scale ◽  
Stress Transfer ◽  
The United States ◽  
Physical Principle ◽  
Static Stress ◽  
Stress Change ◽  
Earthquake Triggering ◽  
Triggered Earthquakes ◽  
Stress Changes

ABSTRACT Coseismic stress changes have been the primary physical principle used to explain aftershocks and triggered earthquakes. However, this method does not adequately forecast earthquake rates and diverse rupture populations when subjected to formal testing. We show that earthquake forecasts can be impaired by assumptions made in physics-based models such as the existence of hypothetical optimal faults and regional scale invariability of the stress field. We compare calculations made under these assumptions along with different realizations of a new conceptual triggering model that features a complete assay of all possible ruptures. In this concept, there always exists a set of theoretical planes that has positive failure stress conditions under a combination of background and coseismic static stress change. In the Earth, all of these theoretical planes may not exist, and if they do, they may not be ready to fail. Thus, the actual aftershock plane may not correspond to the plane with the maximum stress change value. This is consistent with observations that mainshocks commonly activate faults with exotic orientations and rakes. Our testing ground is the M 7.2, 2010 El Mayor–Cucapah earthquake sequence that activated multiple diverse fault populations across the United States–Mexico border in California and Baja California. We carry out a retrospective test involving 748 M≥3.0 triggered earthquakes that occurred during a 3 yr period after the mainshock. We find that a probabilistic expression of possible aftershock planes constrained by premainshock rupture patterns is strongly favored (89% of aftershocks consistent with static stress triggering) versus an optimal fault implementation (35% consistent). Results show that coseismic stress change magnitudes do not necessarily control earthquake triggering, instead we find that the summed background stress and coseismic stress change promotes diverse ruptures. Our model can thus explain earthquake triggering in regions where optimal plane mapping shows coseismic stress reduction.

scholarly journals The 2014 Mw 6.1 Ludian Earthquake: The Application of RADARSAT-2 SAR Interferometry and GPS for this Conjugated Ruptured Event

2019 ◽  
Vol 12 (1) ◽  
pp. 99
Author(s):  
Yufen Niu ◽  
Shuai Wang ◽  
Wu Zhu ◽  
Qin Zhang ◽  
Zhong Lu ◽  
...  
Keyword(s):  
Main Shock ◽  
Surface Deformation ◽  
Large Earthquake ◽  
Failure Stress ◽  
Sar Interferometry ◽  
Coseismic Deformation ◽  
Coulomb Failure Stress ◽  
Ludian Earthquake ◽  
Stress Changes ◽  
Coulomb Failure

Although the Zhaotong–Ludian fault is a seismically active zone located in the boundary between the Sichuan–Yunnan block and the South China block, it has not experienced a large earthquake greater than Mw 7 since at least 1700. On 3 August, 2014, an Mw 6.1 earthquake (the Ludian earthquake) ruptured the Zhaotong active belt in Ludian County, Yunnan province, China. This earthquake was the largest earthquake recorded in the region since 2000, and it provides us with a unique opportunity to study the active tectonics in the region. The analysis of the aftershocks showed that two conjugate faults could have been involved in the event. We first used Global Positioning System (GPS) data and C-band RADARSAT-2 imagery to map the coseismic surface deformation. We then inverted the derived coseismic deformation for the slip distribution based on the constructed conjugate fault model. Finally, the coulomb failure stress due to the Ludian earthquake was estimated to investigate the potential seismic hazards in this region. Our investigations showed that the Ludian earthquake was mainly a bilateral rupture event. The major slip of the main shock was located at depths of 0–5 km, which is close but does not superpose with the aftershocks that are mostly located at depths of 5–20 km. Interestingly, the seismic moment released by the aftershocks (6.9 × 1018 N∙m) was greater than that of the main shock (2.6 × 1018 N∙m). This evidence suggests that the accumulated elastic strain at depths of 0–20 km could have been fully released by the Ludian earthquake and its subsequent aftershocks. Furthermore, our analysis of the coulomb failure stress changes due to the main shock showed that the aftershocks could be the result of dynamic triggering rather than static triggering.

scholarly journals Coulomb stress transfer and fault interaction over millennia on non-planar active normal faults: the Mw 6.5–5.0 seismic sequence of 2016–2017, central Italy

2017 ◽  
Vol 210 (2) ◽  
pp. 1206-1218 ◽  
Author(s):  
Zoe K. Mildon ◽  
Gerald P. Roberts ◽  
Joanna P. Faure Walker ◽  
Francesco Iezzi
Keyword(s):  
Main Shock ◽  
Central Italy ◽  
Stress Transfer ◽  
Historical Record ◽  
Normal Faults ◽  
Coulomb Stress ◽  
Seismic Sequence ◽  
Fault Interaction ◽  
Slip Rates ◽  
Stress Changes

Abstract In order to investigate the importance of including strike-variable geometry and the knowledge of historical and palaeoseismic earthquakes when modelling static Coulomb stress transfer and rupture propagation, we have examined the August–October 2016 A.D. and January 2017 A.D. central Apennines seismic sequence (Mw 6.0, 5.9, 6.5 in 2016 A.D. (INGV) and Mw 5.1, 5.5, 5.4, 5.0 in 2017 A.D. (INGV)). We model both the coseismic loading (from historical and palaeoseismic earthquakes) and interseismic loading (derived from Holocene fault slip-rates) using strike-variable fault geometries constrained by fieldwork. The inclusion of the elapsed times from available historical and palaeoseismological earthquakes and on faults enables us to calculate the stress on the faults prior to the beginning of the seismic sequence. We take account the 1316–4155 yr elapsed time on the Mt. Vettore fault (that ruptured during the 2016 A.D. seismic sequence) implied by palaeoseismology, and the 377 and 313 yr elapsed times on the neighbouring Laga and Norcia faults respectively, indicated by the historical record. The stress changes through time are summed to show the state of stress on the Mt. Vettore, Laga and surrounding faults prior to and during the 2016–2017 A.D. sequence. We show that the build up of stress prior to 2016 A.D. on strike-variable fault geometries generated stress heterogeneities that correlate with the limits of the main-shock ruptures. Hence, we suggest that stress barriers appear to have control on the propagation and therefore the magnitudes of the main-shock ruptures.

Complete Coulomb Failure Stress Changes and Stress Triggering of Yunnan Longling Earthquake Sequence

2007 ◽  
Vol 50 (4) ◽  
pp. 963-974 ◽  
Author(s):  
Xiao-Ping WU ◽  
Hong FU ◽  
Bouchon MICHAEL ◽  
Jia-Fu HU ◽  
Yi-Li HU ◽  
...  
Keyword(s):  
Failure Stress ◽  
Earthquake Sequence ◽  
Coulomb Failure Stress ◽  
Stress Changes ◽  
Coulomb Failure ◽  
Stress Triggering ◽  
Coulomb Failure Stress Changes
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