A Model for Visual Assessment of Fault Plane Solutions and Active Tectonics Analysis Using the Global Centroid Moment Tensor Catalog

We investigate the seismicity occurred in the Po area, in the period July 2011-June 1012, by means of moment tensor and we use our set of revised focal mechanisms - computed for M> 3.7 earthquakes - to evaluate Coulomb elastic stress changes in order to detect potential intermediate-distance faults interaction, and the main features of this complex structural system.

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

JURNAL NEUTRINO ◽

10.18860/neu.v0i0.1650 ◽

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.

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

10.5194/egusphere-egu21-15620 ◽

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

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.&#160; An intense and persistent seismicity is generated between 60 and 180 km depth, within a relic slab sinking nearly vertical in the Earth&#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) >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.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.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>450 Ppl<450). Another characteristic of&#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.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.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.

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

Natural Hazards and Earth System Science ◽

10.5194/nhess-11-2817-2011 ◽

2011 ◽

Vol 11 (10) ◽

pp. 2817-2820 ◽

Cited By ~ 2

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.

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Focal depths and fault plane solutions of earthquakes and active tectonics of the Himalaya

Journal of Geophysical Research Atmospheres ◽

10.1029/jb089ib08p06918 ◽

1984 ◽

Vol 89 (B8) ◽

pp. 6918-6928 ◽

Cited By ~ 138

Author(s):

Jean Baranowski ◽

John Armbruster ◽

Leonardo Seeber ◽

Peter Molnar

Keyword(s):

Fault Plane ◽

Active Tectonics ◽

Fault Plane Solutions ◽

The Himalaya

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A study of the active tectonics and deformation in the Mygdonia basin (N. Greece) using seismological and neotectonic data

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.17027 ◽

2001 ◽

Vol 34 (1) ◽

pp. 303 ◽

Cited By ~ 1

Author(s):

C. B. PAPAZACHOS ◽

D. A. VAMVAKARIS ◽

G. N. VARGEMEZIS ◽

E. V. AIDONA

Keyword(s):

Stress Field ◽

Fault Plane ◽

Average Rate ◽

Active Tectonics ◽

Stress Pattern ◽

Data Sets ◽

Fault Plane Solutions ◽

Small Magnitude ◽

Joint Interpretation ◽

Geomorphological Changes

In the present work we study the active tectonics setting and related deformation scheme in the Mygdonia basin, on the basis of the joint interpretation of seismological and neotectonic data. For this reason, the stress field derived from fault plane solutions of small-magnitude events from a local seismological experiment, as well as neotectonic observations are studied in order to determine its spatial distribution. The results show an almost identical spatial variation of the stress field determined from the two independent data sets, which also exhibits a very good correlation with the geomorphological changes in the Mygdonia basin. Moreover, the average stress field is almost identical to the corresponding stress pattern determined from the 3 largest events in the study area for which reliable fault plane solutions are available. Using the combined stress pattern and the corresponding moment-rate tensors derived from both data sets, the active crustal deformation is studied for the most active sections of the Mygdonia basin system. The results show a N-S extension at an average rate of 3mm/ yr for the central part of the Mygdonia system, in very good agreement with the available geodetic results.

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

10.21203/rs.3.rs-18454/v1 ◽

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.

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

Iraqi Journal of Science ◽

10.24996/ijs.2020.61.7.18 ◽

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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