scholarly journals Can hydrocarbon extraction from the crust enhance or inhibit seismicity in tectonically active regions? A statistical study in Italy

2021 ◽  
Author(s):  
Alexander Garcia ◽  
Licia Faenza ◽  
Andrea Morelli ◽  
Ilaria Antoncecchi
Keyword(s):  
Statistical Study ◽  
Active Regions ◽  
Tectonically Active ◽  
Hydrocarbon Extraction

scholarly journals Estimation of absolute stress in the hypocentral region of the 2019 Ridgecrest, California, earthquakes

2020 ◽  
Author(s):  
Yuri Fialko
Keyword(s):  
Seismic Data ◽  
Plate Tectonics ◽  
Active Faults ◽  
Active Regions ◽  
Seismogenic Zone ◽  
Shear Stresses ◽  
Strong Earthquakes ◽  
Frictional Strength ◽  
Tectonically Active ◽  
Weak Fault

Abstract Strength of the upper brittle part of the Earth's lithosphere controls deformation styles in tectonically active regions, surface topography, seismicity, and the occurrence of plate tectonics, yet it remains one of the least constrained and most debated quantities in geophysics. Seismic data (in particular, earthquake focal mechanisms) have been used to infer orientation of the principal stress axes. Here I show that the focal mechanism data can be combined with information from precise earthquake locations to place robust constraints not only on the orientation, but also on the magnitude of absolute stress at depth. The proposed method uses machine learning to identify quasi-linear clusters of seismicity associated with active faults. A distribution of the relative attitudes of conjugate faults carries information about the amplitude and spatial heterogeneity of the deviatoric stress and frictional strength in the seismogenic zone. The observed diversity of dihedral angles between conjugate faults in the Ridgecrest (California, USA) area that hosted a recent sequence of strong earthquakes suggests the effective coefficient of friction of 0.4-0.6, and depth-averaged shear stresses on the order of 25-40 MPa, intermediate between predictions of the "strong" and "weak" fault theories.

scholarly journals Moment magnitude estimates for Central Anatolian earthquakes using coda waves

2019 ◽  
Author(s):  
Tuna Eken
Keyword(s):  
Empirical Relation ◽  
Active Regions ◽  
Moment Magnitude ◽  
Central Anatolia ◽  
Coda Wave ◽  
Seismic Experiment ◽  
Tectonically Active ◽  
Passive Seismic ◽  
Passive Seismic Experiment ◽  
Good Agreement

Abstract. Proper estimate of moment magnitude that is a physical measure of the energy released at earthquake source is essential for better seismic hazard assessments in tectonically active regions. Here a coda wave modeling approach that enables the source displacement spectrum modeling of examined event was used to estimate moment magnitude of central Anatolia earthquakes. To achieve this aim, three component waveforms of local earthquakes with magnitudes 2.0 ≤ ML ≤ 5.2 recorded at 72 seismic stations which have been operated between 2013 and 2015 within the framework of the CD-CAT passive seismic experiment. An inversion on the coda wave traces of each selected single event in our database was performed in five different frequency bands between 0.75 and 12 Hz. Our resultant moment magnitudes (MW-coda) exhibit a good agreement with routinely reported local magnitude (ML) estimates for study area. Finally, we present an empirical relation between MW-coda and ML for central Anatolian earthquakes.

scholarly journals The origins and implications of paleochannels in hyperarid, tectonically active regions: The northern Atacama Desert, Chile

2020 ◽  
Vol 185 ◽  
pp. 103083 ◽  
Author(s):  
S.A. Binnie ◽  
K.R. Reicherter ◽  
P. Victor ◽  
G. González ◽  
A. Binnie ◽  
...  
Keyword(s):  
Atacama Desert ◽  
Active Regions ◽  
Tectonically Active

A Statistical Study of the Relation between the Amplitude of Solar Cycle and the Area of Active Regions

2014 ◽  
Vol 38 (4) ◽  
pp. 448-453
Author(s):  
LI Peng ◽  
LE Gui-ming ◽  
CHEN Yu-lin ◽  
CHEN Min-hao ◽  
LU Yang-ping ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Statistical Study ◽  
Active Regions

scholarly journals GROUND SURFACE VISUALIZATION USING RED RELIEF IMAGE MAP FOR A VARIETY OF MAP SCALES

2016 ◽  
Vol XLI-B2 ◽  
pp. 393-397 ◽  
Author(s):  
T. Chiba ◽  
B. Hasi
Keyword(s):  
Ground Surface ◽  
Active Regions ◽  
Surface Expression ◽  
Digital Data ◽  
Quality Data ◽  
Surface Model ◽  
Contour Map ◽  
High Quality Data ◽  
Tectonically Active ◽  
Surface Visualization

There are many methods to express topographical features of ground surface. In which, contour map has been the traditional method and along with development of digital data, surface model such as shaded relief map has been using for ground surface expression. Recently, data acquisition has been developed very much quick, demanding more advanced visualization method to express ground surface so as to effectively use the high quality data. In this study, the authors using the Red Relief Image Map (RRIM, Chiba et al., 2008) to express ground surface visualization for a variety of map scales. The authors used 30 m mesh data of SRTM to show the topographical features of western Mongolian and micro-topographical features of ground surface in tectonically active regions of Japan. The results show that, compared to traditional and other similar methods, the RRIM can express ground surface more precisely and 3-dimensionally, suggested its advanced usage for many fields of topographical visualization.

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