Characteristics of Seismicity in the Eagle Ford Shale Play, Southern Texas, Constrained by Earthquake Relocation and Centroid Moment Tensor Inversion

2021 ◽  
Author(s):  
Peng Li ◽  
Guo-Chin D. Huang ◽  
Alexandros Savvaidis ◽  
Florentia Kavoura ◽  
Robert W. Porritt
Keyword(s):  
Stress Field ◽  
Energy Release ◽  
Fault Plane ◽  
Anthropogenic Activities ◽  
Moment Tensor ◽  
Normal Fault ◽  
Strike Slip ◽  
Eagle Ford Shale ◽  
Eagle Ford ◽  
Earthquake Energy

Abstract Analysis of earthquake locations and centroid moment tensors (CMTs) is critical in assessing seismogenic structures and connecting earthquakes to anthropogenic activities. The objective of this study was to gain insights into the seismotectonics of the Eagle Ford Shale play (EF), southern Texas, through relative relocation of earthquakes, assessment of CMT solutions, and investigation of the background stress field. Using Texas Seismological Network (TexNet) data from 2017 through 2019, we were able to relocate 326 earthquakes and obtain CMT solutions for 37 ML≥2.0 earthquakes. These earthquakes are located in the sedimentary basin and uppermost crust, with depths ranging from 2 to 10 km. The earthquake groups in the northeastern EF are linearly distributed along the Karnes fault zone, whereas the southern and western groups are spatially scattered around mapped or unmapped faults. CMT solutions identified 32 normal fault earthquakes and five strike-slip earthquakes. The orientation of the fault plane of most normal fault earthquakes is southwest–northeast, whereas the possible fault plane of the strike-slip fault is from north-northwest to south-southeast, which is roughly perpendicular to the normal faults. Normal and strike-slip faults in the EF are of high dip angles, with the dip angles of the most faults ranging from 60° to 80°. Stress inversion results show that the major orientation of maximum horizontal stress (SHmax) is southwest–northeast, with minor local stress-field rotations. We further estimated earthquake energy release in the EF region using moment magnitude from the CMT solutions, and the cumulative earthquake energy release curve reveals three notable increases in cumulative seismic moment, which occurred in January–July 2018 and January–March 2019, and May–August 2019. Whether these energy releases were caused by anthropogenic activities is a matter for further investigation.

A teleseismic body-wave analysis of the May 1980 Mammoth Lakes, California, earthquakes

1983 ◽  
Vol 73 (2) ◽  
pp. 419-434
Author(s):  
Jeffery S. Barker ◽  
Charles A. Langston
Keyword(s):  
Body Wave ◽  
Moment Tensor ◽  
Normal Fault ◽  
Strike Slip ◽  
Body Waves ◽  
P Wave ◽  
Moment Tensors ◽  
Double Couple ◽  
The Moment ◽  
Mammoth Lakes

abstract Teleseismic P-wave first motions for the M ≧ 6 earthquakes near Mammoth Lakes, California, are inconsistent with the vertical strike-slip mechanisms determined from local and regional P-wave first motions. Combining these data sets allows three possible mechanisms: a north-striking, east-dipping strike-slip fault; a NE-striking oblique fault; and a NNW-striking normal fault. Inversion of long-period teleseismic P and SH waves for the events of 25 May 1980 (1633 UTC) and 27 May 1980 (1450 UTC) yields moment tensors with large non-double-couple components. The moment tensor for the first event may be decomposed into a major double couple with strike = 18°, dip = 61°, and rake = −15°, and a minor double couple with strike = 303°, dip = 43°, and rake = 224°. A similar decomposition for the last event yields strike = 25°, dip = 65°, rake = −6°, and strike = 312°, dip = 37°, and rake = 232°. Although the inversions were performed on only a few teleseismic body waves, the radiation patterns of the moment tensors are consistent with most of the P-wave first motion polarities at local, regional, and teleseismic distances. The stress axes inferred from the moment tensors are consistent with N65°E extension determined by geodetic measurements by Savage et al. (1981). Seismic moments computed from the moment tensors are 1.87 × 1025 dyne-cm for the 25 May 1980 (1633 UTC) event and 1.03 × 1025 dyne-cm for the 27 May 1980 (1450 UTC) event. The non-double-couple aspect of the moment tensors and the inability to obtain a convergent solution for the 25 May 1980 (1944 UTC) event may indicate that the assumptions of a point source and plane-layered structure implicit in the moment tensor inversion are not entirely valid for the Mammoth Lakes earthquakes.

A New Uniform Moment Tensor Catalog for Yunnan, China, from January 2000 through December 2014

2020 ◽  
Vol 91 (2A) ◽  
pp. 891-900
Author(s):  
Yan Xu ◽  
Keith D. Koper ◽  
Relu Burlacu ◽  
Robert B. Herrmann ◽  
Dan-Ning Li
Keyword(s):  
Stress Field ◽  
Seismic Hazard ◽  
Moment Tensor ◽  
Horizontal Stress ◽  
Strike Slip ◽  
Moment Tensors ◽  
Yunnan Region ◽  
Seismic Waveforms ◽  
The Moment ◽  
Maximum Horizontal Stress

Abstract Because of the collision of the Indian and Eurasian tectonic plates, the Yunnan Province of southwestern China has some of the highest levels of seismic hazard in the world. In such a region, a catalog of moment tensors is important for estimating seismic hazard and helping understand the regional seismotectonics. Here, we present a new uniform catalog of moment tensor solutions for the Yunnan region. Using a grid-search technique to invert seismic waveforms recorded by the permanent regional network in Yunnan and the 2 yr ChinArray deployment, we present 1833 moment tensor solutions for small-to-moderate earthquakes that occurred between January 2000 and December 2014. Moment magnitudes in the new catalog vary from Mw 2.2 to 6.1, and the catalog is complete above Mw∼3.5–3.6. The moment tensors are constrained to be purely double-couple and show a variety of faulting mechanisms. Normal faulting events are mainly concentrated in northwest Yunnan, while farther south along the Sagaing fault the earthquakes are mostly thrust and strike slip. The remaining area includes all three styles of faulting but mostly strike slip. We invert the moment tensors for the regional stress field and find a strong correlation between spatially varying maximum horizontal stress and Global Positioning System observations of horizontal ground velocity. The stress field reveals clockwise rotation around the eastern Himalayan syntaxis, with northwest–southeast compression to the east of the Red River fault changing to northeast–southwest compression west of the fault. Almost 88% of the centroid depths are shallower than 16 km, consistent with a weak and ductile lower crust.

Spatial variation in the present-day stress field and tectonic regime of Northeast Tibet from moment tensor solutions of local earthquake data

2020 ◽  
Vol 221 (1) ◽  
pp. 478-491 ◽  
Author(s):  
Zhengyang Pan ◽  
Jiankun He ◽  
Zhigang Shao
Keyword(s):  
Stress Field ◽  
Compressive Stress ◽  
Moment Tensor ◽  
Strike Slip ◽  
Focal Mechanisms ◽  
Qilian Mountains ◽  
Compression Axis ◽  
The South ◽  
Maximum Compression ◽  
Stress Orientation

SUMMARY Focal mechanism solutions and their predicted stress pattern can be used to investigate tectonic deformation in seismically active zones and contribute to understanding and constraining the kinematic patterns of the outward growth and uplift of the Tibetan Plateau. Herein, we determined the focal mechanisms of 398 earthquakes in Northeast Tibet recorded by the China National Seismic Network (CNSN) by using the cut-and-paste method. The results show that the earthquakes predominately exhibited thrust and strike-slip faulting mechanisms with very few normal events. We then combined the derived focal mechanisms with global centroid moment tensor (GCMT) catalogue solutions and previously published solutions to predict the regional distribution of the stress field through a damped linear inversion. The inversion results show that most of region is dominated by a thrust faulting regime. From the southern East Kunlun fault in the west to the northern Qilian Mountains along the Altyn Tagh fault (ATF), the maximum compression axis rotates slightly clockwise; farther to the south of the Haiyuan fault in the east, there is an evident clockwise rotation of the maximum compression axis, especially at the eastern end of the Haiyuan fault. In the Qilian Mountains, the axis of the compressive stress orientation approximately trends NE–SW, which does not markedly differ from the direction of India–Eurasia convergence, emphasizing the importance of the compressive stress in reflecting the remote effects of this continental collision. The overall spatial pattern of the principal stress axes is closely consistent with the GPS-derived horizontal surface velocity. A comparison of the stress and strain rate fields demonstrated that the orientations of the crustal stress axes and the surface strain axes were almost identical, which indicates that a diffuse model is more suitable for describing the tectonic characteristics of Northeast Tibet. Additionally, the compressive stress orientation rotated to ENE–WSW in the northern Qilian Mountains along the ATF and to ENE–WSW or E–W along the eastern part of the Haiyuan fault and its adjacent area to the south, highlighting the occurrence of strain partitioning along large left-lateral strike-slip faults or the lateral variation of crustal strength across these faults. Combining geodetic, geological and seismological results, we suggest that a hybrid model incorporating both the diffuse model associated with shortening and thickening of the upper crust and the asthenospheric flow model accounting for the low-velocity zone in the middle-lower crust may reflect the primary mode of crustal deformation in Northeast Tibet.

scholarly journals ANALISIS SEISMOGRAM TIGA KOMPONEN TERHADAP MOMENT TENSOR GEMPA BUMI DI MANOKWARI PAPUA 03 JANUARI 2009

2012 ◽  
Author(s):  
Irwan Setyowidodo, Bagus Jaya Santosa
Keyword(s):  
Fault Plane ◽  
Moment Tensor ◽  
Strike Slip ◽  
Centroid Moment Tensor

Penelitian ini melakukan analisis inversi waveform 3 komponen terhadap data gempa bumi yang  terjadi  di  Manokwari  Papua  pada  tanggal  3  Januari  2009  pukul  19:43:55  GMT  dengan magnitude  7.1  Mw  yang  episentrumnya  berada  pada  lattitude  -0.70541,  longitude  125.8455  dan kedalaman 25 km. Data yang digunakan dalam penelitian ialah, data seismik lokal yang diunduh dari data  gempa  IA.  Selanjutnya  dilakukan  proses   inversi  data  waveform  tiga  komponen  dengan menggunakan  metode  iterasi  dekonvolusi.  Metode  ini  diimplementasikan  dalam  software  ISOLA yang  dikembangkan   untuk  mendapatkan  parameter-parameter  sumber  gempa  bumi.  Parameter- parameter  gempa ini tergambarkan dalam Centroid Moment Tensor dan parameter sesar penyebab gempa. Selanjutnya, hasil parameter-patameter  tersebut digunakan untuk  mengetahui arah  patahan yang sebenarnya (fault-plane) dengan menggunakan metode H-C. Seismogram sintetik dihitung dengan ISOLA yang inputnya adalah model bumi dan data seismogram yang  direkam  oleh  stasiun  seismologi  BAK,  LBM  dan  JAY.  Hasil   interpretasi  atas  analisis seismogram   waveform   tiga   komponen   menunjukkan   bahwa   orientasi   bidang   patahan   gempa Manokwari Papua pada tanggal 3 Januari 2009 memiliki sudut dip 54o       terhadap bidang  horizontal yang menyebabkan zona patahan di daerah tersebut mudah bergeser dan mudah terjadi gempa. Hasil analisis  ini  diketahui  bahwa  sesar  penyebab  gempa  bumi  ini  ialah  sesar  strike-slip  oblique  yang bergerak dari  arah barat  laut - tenggara. Sumber  gempa  bumi  yang terjadi tersebut terjadi akibat aktivitas Sesar Sorong yang terdapat di bagian utara Manokwari.<br /><br /><br /><br />

Tectonic stress patterns along the Vrancea subcrustal zone from the inversion of focal mechanisms data

2021 ◽  
Author(s):  
Andreea Craiu ◽  
Marius Craiu ◽  
Mariu Mihai ◽  
Elena Manea ◽  
Alexandru Marmureanu
Keyword(s):  
Stress Field ◽  
Large Scale ◽  
Fault Plane ◽  
Numerical Models ◽  
Moment Tensor ◽  
Stress Inversion ◽  
Slab Geometry ◽  
Fault Plane Solutions ◽  
Current Stress ◽  
Stress Patterns

&lt;p&gt;The Vrancea zone is an unique area with both crustal and intermediate-depth seismic activity and constitutes one of the most active seismic area in Europe.&amp;#160; An intense and persistent seismicity is generated between 60 and 180 km depth, within a relic slab sinking nearly vertical in the Earth&amp;#8217;s mantle due to the increasing of the stress state within this volume. At intermediate-depths, large magnitude events are frequent, i.e. four earthquakes with moment magnitudes (Mw) &gt;7 occurred in the last century. An unique slab geometry, likely preserved until the present, causes stress localization due to the slab bending and subsequent stress release resulting in large mantle earthquakes in the region.&lt;/p&gt;&lt;p&gt;In this study, we evaluate the current stress field along the Vrancea subcrustal region by computing the fault plane solutions of 422 seismic events since January 2005. The continuous development of the National Seismic Network allows us to constrain the fault plane solutions and subsequently to evaluate the current stress field.&lt;/p&gt;&lt;p&gt;The main style of faulting for Vrancea subcrustal events presents a predominant reverse one, with two main earthquakes categories: the first one with the nodal planes oriented NE-SW parallel with the Carpathian Arc and the second one with the nodal planes oriented NW-SE perpendicular on the Carpathian Arc. The main axis of the moment tensor may indicate a predominant compressional stress field (Tpl&gt;45&lt;sup&gt;0&lt;/sup&gt; Ppl&lt;45&lt;sup&gt;0&lt;/sup&gt;). Another characteristic of&amp;#160; the Vrancea subcrustal zone is the tendency of the extension axis T to be almost vertical and the compression axis P being almost horizontal.&lt;/p&gt;&lt;p&gt;The results of stress inversion indicate a dominant reverse faulting style, with an average stress regime index of 2.9. Other tectonic regimes were observed in the present dataset as normal and strike-slip but they are retrieved for a restrained number of events.&lt;/p&gt;&lt;p&gt;The stress patterns obtained from formal stress inversion of focal mechanism solutions reveal many features of the current stress field that were not captured by large-scale numerical models.&lt;/p&gt;

scholarly journals The stress field of Vrancea region from fault plane solution (FPS)

2011 ◽  
Vol 11 (10) ◽  
pp. 2817-2820 ◽  
Author(s):  
L. Telesca ◽  
V. Alcaz ◽  
I. Sandu
Keyword(s):  
Stress Field ◽  
Fault Plane ◽  
Moment Tensor ◽  
Field Investigation ◽  
Seismic Region ◽  
Fault Plane Solutions ◽  
Intermediate Depth ◽  
Vrancea Region ◽  
Plane Solution ◽  
Vrancea Seismic Region

Abstract. The fault plane solutions (FPS) of 247 seismic events were used for stress field investigation of the region. The eigenvectors t, p, b, and moment tensor M components for each FPS were defined and computed numerically. The obtained results confirm the hypothesis of subduction-type intermediate depth earthquakes for the Vrancea seismic region and this may be considered the first approximation of the stress field for the whole of the Vrancea (intermediate depth) region.

scholarly journals Analisa Pola Sesar Di Daratan Selatan Sumatera Berdasarkan Event Gempa Tahun 1960-2000

2017 ◽  
Vol 3 (2) ◽  
Author(s):  
A. M Miftahul Huda ◽  
Badrul Munir
Keyword(s):  
Moment Tensor ◽  
Normal Fault ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Reverse Fault

Analisa pola sesar telah dilakukan untuk wilayah sumatera bagian selatan melalui analisis data kegempaan. Data kegempaan yang digunakan adalah data ISC dan dikombinasikan dengan data fokal dari Global CMT dari tahun 1960-2000. Penelitian ini dilakukan dalam tiga tahap, yaitu penentuan persebaran kegempaan, penentuan moment tensor melalui data fokal, dan korelasi data dengan data geologi. Pada posisi geografis 1040-1060 BT terdapat 7 gempa signifikan sepanjang tahun 1960 sampai tahun 2000, diantaranya 3 sesar mendatar (strike slip fault), 1 sesar naik (reverse fault), 1 sesar turun (normal fault) dan 2 sesar oblique. Anomali data terjadi pada seismisitas kegempaan tahun 1960-2000, yaitu teramatinya sesar oblique. Aktifitas kegempaan dipengaruhi oleh aktifitas sesar Sumatera dari Andaman sampai Semangko. Kata kunci: pola sesar, gempa tektonik, fokal, oblique

scholarly journals Stress distribution and seismicity patterns of the 2011 seismic swarm in the Messinia basin, (South-Western Peloponnesus), Greece

2013 ◽  
Vol 13 (1) ◽  
pp. 45-51 ◽  
Author(s):  
G. Chouliaras ◽  
G. Drakatos ◽  
K. Pavlou ◽  
K. Makropoulos
Keyword(s):  
Stress Field ◽  
Moment Tensor ◽  
Normal Fault ◽  
Local Stress ◽  
B Value ◽  
Seismic Gap ◽  
Seismicity Patterns ◽  
Centroid Moment Tensor ◽  
Seismicity Rate ◽  
The North

Abstract. In this investigation we examine the local stress field and the seismicity patterns associated with the 2011–2012 seismicity swarm in the Messinia basin, south-western Peloponnesus, Greece, using the seismological data of the National Observatory of Athens (NOA). During this swarm more than 2000 events were recorded in a 12 month period by the Hellenic Unified Seismological Network (HUSN) and also by the additional local installation of four portable broadband seismographic stations by NOA. The results indicate a Gaussian distribution of swarm activity and the development of a seismicity cluster in a pre-existing seismic gap within the Messinia basin. Centroid Moment Tensor solutions demonstrate a normal fault trending northwest–southeast and dipping to the southwest primarily due to an extensional stress field. During this seismicity swarm an epicentre migration of the three largest shocks is observed, from one end of the rupture zone in the north-western part of the cluster, towards the other edge of the rupture in the south-eastern part of the cluster. This migration is found to follow the Coulomb failure criterion that predicts the advancement and retardation of the stress field and the patterns of increases and decreases of the seismicity rate (b-value) of the frequency–magnitude relation.

scholarly journals The rate of Seismic deformation in the Gulf of Aqaba as inferred from moment tensor summation

2020 ◽  
Author(s):  
Sattam Almadani
Keyword(s):  
Shear Deformation ◽  
Fault Plane ◽  
Moment Tensor ◽  
Strike Slip ◽  
Gulf Of Aqaba ◽  
Fault Plane Solutions ◽  
Seismicity Parameters ◽  
Fault Parameters ◽  
The Moment ◽  
Seismic Deformation

Abstract The main goal of this study is to quantify the rate of seismic deformation in the Gulf of Aqaba. The moment tensor summation technique based on the seismicity data, for all available historical and instrumental data (1900-2019), and reliable fault plane solutions was used to calculate the size and the shape of deformation. For the period from 1900 to 2019, the seismicity data was used to calculate the seismicity parameters (representing by the Gutenberg-Richter and moment-magnitude relations) and the spatial extent of the deformation zone. The fault parameters of forty-four earthquakes, having moment magnitudes range from 3.2 to 7.2, were used to construct the moment tensor summation and subsequently to calculate the rate of seismic deformation. The calculations showed that a predominant shear deformation acting in the Gulf of Aqaba is taken up by extension in a direction of N40.8 o E at a rate of 0.83±0.21 mm/yr. and compression in a direction of N131.6 o E at a rate of 0.32±0.05 mm/yr.; reflecting the Gulf of Aqaba is undergoing from shear deformation accommodated along a strike-slip fault. The obtained results exhibited that the present-day deformation in the Gulf of Aqaba is acting by the interaction of relative tectonic motions among African, Sinai and Arabia plates.

scholarly journals Seismotectonics and Seismic Source Parameters of the Mid-Eastern Iraq - Western Iran Using Moment Tensor Inversion Technique

2020 ◽  
pp. 1691-1704
Author(s):  
Hasanain Jasim Mohammed ◽  
Ali M. Al-Rahim
Keyword(s):  
Fault Plane ◽  
Moment Tensor ◽  
Source Parameters ◽  
Strike Slip ◽  
Moment Tensor Inversion ◽  
Arabian Plate ◽  
Good Match ◽  
Local Magnitude ◽  
Fault Plane Solutions ◽  
Inversion Technique

     The study area is encompassed by the 33.59-34.93°N latitudes and 45.44-46.39°E longitudes and divided into four groups with respect to earthquake event locations. We determined fault plane solutions, moment magnitudes, focal depths, and trend of slip with the direction of the moment stress axes (P, N, and T) for 102 earthquakes. These earthquakes had a local magnitude in the range between 4.0 and 6.4 for the time period from January 2018 to the end of August 2019, with focal depths ranged between 6 and 17 km. Waveform moment tensor inversion technique was used to analyze the database constructed from seismic stations on local and neighboring country networks (Iraq, Iran, and Turkey). We separated the studied events into four regional subsets (circles). The types of the obtained fault plane solutions are predominantly thrust fault and strike-slip, with the focal depths ranging from 8 to 21 km.      A new scaling relation between local magnitude (Ml) and the estimated moment magnitude (Mw) has been developed utilizing a linear regression. Good match results obtained in the present research good match with both seismic trends concluded from earthquake locations and mapped faults. Generally, direction shows NW–SE striking focal planes corresponding with the tectonic framework of the Arabian–Eurasian continental collision zone. The anticlockwise rotation of the Arabian plate that appears accountable for strike-slip displacements on fault surfaces.

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