TECTONIC SETTING OF THE 2019-2020 PUERTO RICO EARTHQUAKE SWARM BASED ON INTEGRATION OF ACTIVE FAULTS, EARTHQUAKE FOCAL MECHANISMS, AND TECTONIC GEOMORPHOLOGY

2020 ◽  
Author(s):  
Lei Sun ◽  
◽  
Paul Mann ◽  
Jean-Claude Hippolyte
Keyword(s):  
Puerto Rico ◽  
Tectonic Setting ◽  
Earthquake Swarm ◽  
Active Faults ◽  
Focal Mechanisms ◽  
Tectonic Geomorphology ◽  
Earthquake Focal Mechanisms

scholarly journals FMHex20: A database of earthquake focal mechanisms in metropolitan France and conterminous Western Europe

2020 ◽  
Author(s):  
Stephane Mazzotti ◽  
Clémence Aubagnac ◽  
Laurent Bollinger ◽  
Karla Coca Oscanoa ◽  
Bertrand Delouis ◽  
...  
Keyword(s):  
Western Europe ◽  
Active Faults ◽  
Focal Mechanisms ◽  
Hazard Zonation ◽  
First Order ◽  
Focal Mechanism Solutions ◽  
Earthquake Focal Mechanisms ◽  
Ongoing Effort ◽  
Low Strain Rate ◽  
Northern Alps

We present a compilation of over 1700 focal mechanisms for nearly 1300 earthquakes in metropolitan France and conterminous Western Europe. It is based on both published and unpublished sources (articles, reports, observatory websites) for which the focal mechanism solutions have been verified for internal consistency, corrected in cases of minor errors and rejected in cases of major inconsistencies between the parameters. The database, labeled FMHex20, is a first version and should be regularly updated in the future as part of an ongoing effort within the Seismicity Transverse Action of the French RESIF research infrastructure. We also present first-order seismotectonic analyses for the whole metropolitan France and for a couple of example regions (Western France and Northern Alps-Jura-Vosges) to illustrate how the FMHex20 database can serve as a basis for geodynamic or seismic hazard zonation studies. Combined with complementary datasets, it can improve our understanding of the kinematics of potentially active faults, including in very-low-strain-rate regions as is the case for most of metropolitan France.

Present-day tectonic stress regime in Egypt and surrounding area based on inversion of earthquake focal mechanisms

2013 ◽  
Vol 81 ◽  
pp. 1-15 ◽  
Author(s):  
H.M. Hussein ◽  
K.M. Abou Elenean ◽  
I.A. Marzouk ◽  
I.M. Korrat ◽  
I.F. Abu El-Nader ◽  
...  
Keyword(s):  
Tectonic Stress ◽  
Focal Mechanisms ◽  
Surrounding Area ◽  
Stress Regime ◽  
Earthquake Focal Mechanisms

Earthquake focal mechanisms, deformation state, and seismotectonics of the Pamir-Tien Shan region, Central Asia

1995 ◽  
Vol 100 (B10) ◽  
pp. 20321-20343 ◽  
Author(s):  
Albert A. Lukk ◽  
Sergei L. Yunga ◽  
Vladimir I. Shevchenko ◽  
Michael W. Hamburger
Keyword(s):  
Central Asia ◽  
Focal Mechanisms ◽  
Tien Shan ◽  
Earthquake Focal Mechanisms ◽  
Deformation State

Looking for the hidden morphological signature of active faults in a Low Strain Rate region: clues from the eastern Kachchh region (NW India) 

2021 ◽  
Author(s):  
Eshaan Srivastava ◽  
Nicolò Parrino ◽  
Javed Malik ◽  
Fabrizio Pepe ◽  
Pierfrancesco Burrato
Keyword(s):  
Strain Rate ◽  
Multidisciplinary Approach ◽  
Surface Deformation ◽  
Active Faults ◽  
Tectonic Geomorphology ◽  
Seismic Events ◽  
Rate Region ◽  
Ongoing Work ◽  
Morphotectonic Evolution ◽  
Low Strain Rate

<p>The Kachchh region (NW India), a pericratonic rift basin delimited by E-W trending major thrust faults, is a Low Strain Rate region[PB1] . In this area, the tectonic forcing magnitude is stronger enough to trigger infrequent significant earthquakes but not enough to overprint the climatic forcing signature. As a consequence, the active faults sources of the largest seismic events are largely poorly known and their geomorphic signature is subdued. </p><p>Instrumental and paleoseismological evidence highlights that the eastern part of Kachchh experienced a significant number of seismic events such as the 1819-06-16 Allah Bund earthquake (Mw 7.8, also known as the Rann of Kutch earthquake), the 1956-07-21 Anjar earthquake (Mw 6.1), the 2001-01-26 Bhuj earthquake (Mw 7.6) and the 2006 events (Mw 5.0 and 5.6 earthquake occurred along Island Belt Fault and Gedi fault). </p><p>In this region, the unavailability of useful outcrop information due to a significant climatic overprinting of the fault’s morphological signatures hampers the detection and parametrization of actively deforming faults.</p><p>For this reason, in this ongoing work, we propose a multidisciplinary approach, aimed at detecting active geological structures and their related [PB2] surface deformation, which mainly consists of quantitative tectonic geomorphology and paleoseismological analyses and structural interpretation and modelling. Preliminary results are a morphotectonic evolution model and 3D fault model of the study area. Finally, we stress the concept that only a multidisciplinary approach could provide useful information to understand better the highly debated active tectonic framework of the study area.</p>

Earthquake Focal Mechanisms in the New Madrid Seismic Zone

2014 ◽  
Vol 85 (2) ◽  
pp. 257-267 ◽  
Author(s):  
G. A. Johnson ◽  
S. P. Horton ◽  
M. Withers ◽  
R. Cox
Keyword(s):  
Focal Mechanisms ◽  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Earthquake Focal Mechanisms ◽  
New Madrid

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 Tectonic stress regime in the 2003–2004 and 2012–2015 earthquake swarms in the Ubaye Valley, French Alps

2018 ◽  
Vol 175 (6) ◽  
pp. 1997-2008 ◽  
Author(s):  
Lucia Fojtíková ◽  
Václav Vavryčuk
Keyword(s):  
Seismic Activity ◽  
Joint Inversion ◽  
Earthquake Swarm ◽  
Active Faults ◽  
Tectonic Stress ◽  
Geological Mapping ◽  
Earthquake Swarms ◽  
Stress Regime ◽  
French Alps ◽  
Principal Axes

Abstract We study two earthquake swarms that occurred in the Ubaye Valley, French Alps within the past decade: the 2003–2004 earthquake swarm with the strongest shock of magnitude ML = 2.7, and the 2012–2015 earthquake swarm with the strongest shock of magnitude ML = 4.8. The 2003–2004 seismic activity clustered along a 9-km-long rupture zone at depth between 3 and 8 km. The 2012–2015 activity occurred a few kilometres to the northwest from the previous one. We applied the iterative joint inversion for stress and fault orientations developed by Vavryčuk (2014) to focal mechanisms of 74 events of the 2003–2004 swarm and of 13 strongest events of the 2012–2015 swarm. The retrieved stress regime is consistent for both seismic activities. The σ 3 principal axis is nearly horizontal with azimuth of ~ 103°. The σ 1 and σ 2 principal axes are inclined and their stress magnitudes are similar. The active faults are optimally oriented for shear faulting with respect to tectonic stress and differ from major fault systems known from geological mapping in the region. The estimated low value of friction coefficient at the faults 0.2–0.3 supports an idea of seismic activity triggered or strongly affected by presence of fluids.

Sign in / Sign up

Export Citation Format

Share Document