scholarly journals Disjunctive dislocations of the upper crust of Tien Shan

2019 ◽  
Vol 484 (3) ◽  
pp. 316-319
Author(s):  
V. S. Burtman
Keyword(s):  
Active Faults ◽  
Tien Shan ◽  
Late Paleozoic ◽  
Seismic Events ◽  
Upper Crust ◽  
No Formation ◽  
The Rose

This paper analyzes the rose diagrams of the directions of 439 faults of the Variscian province, 476 faults of the Caledonian province, and 603 presently active faults of Tien Shan. It is shown that more than half of the faults of the Caledonian province of Tien Shan are a result of Late Paleozoic orogenesis, which spanned its entire territory. Our data indicate that seismic events of Tien Shan have resulted in no formation of new disjunctive dislocation in many cases exhibiting displacements along Paleozoic faults.

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>

scholarly journals Identification of Paleoearthquakes and Coseismic Slips on a Normal Fault Using High-Precision Quantitative Morphology: Application to the Jiaocheng Fault in the Shanxi Rift, China

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 2) ◽  
Author(s):  
Junjie Zou ◽  
Honglin He ◽  
Yusuke Yokoyama ◽  
Adam D. Sproson ◽  
Yoshiki Shirahama ◽  
...  
Keyword(s):  
Active Faults ◽  
Normal Fault ◽  
Seismic Events ◽  
Quantitative Morphology ◽  
Coseismic Slip ◽  
Slip History ◽  
Absolute Dating ◽  
Future Work ◽  
Shanxi Rift

Abstract The quantitative morphology of bedrock fault surfaces combined with aerial surveys and field identification is a useful approach to identify paleoearthquakes, obtain coseismic slips, and evaluate the seismogenic capacity of active faults in bedrock areas where traditional trenching methods are not applicable. Here, we report a case study of the Jiaocheng Fault (JCF) in the Shanxi Rift, China. Although several studies have been conducted on the JCF, its coseismic slip history and seismogenic capacity are still unclear. To address these problems, we investigated two bedrock fault surfaces, Sixicun (SXC) and Shanglanzhen (SLZ), on the JCF’s northern segment using quantitative morphological analysis together with aerial and field surveys. Quantitative fractal analysis based on the isotropic empirical variogram and moving window shows that both bedrock fault surfaces have the characteristics of vertical segmentation, which is likely due to periodic earthquakes, the coseismic slip of which can be determined by the height of the segments. Three seismic events at SXC, with a coseismic vertical slip of 1.74, 1.65, and 1.99 m, and three seismic events at SLZ, with a coseismic vertical slip of 1.32, 2.35, and 1.88 m, are identified. Compared with the previous studies, these three seismic events may occur in the Holocene, but it requires absolute dating ages to support, which is also the focus of our future work. Considering the seismologic capability (M>7.5) and the relationship between the recurrence interval of ~2.6 kyr and elapsed time of more than 3 kyr, the seismic hazard of the northern and middle segments of the JCF requires immediate attention.

scholarly journals Intrusion of UHP metamorphic rocks into the upper crust of Kyrgyzian Tien-Shan: P-T path and metamorphic age of the Makbal Complex

2010 ◽  
Vol 105 (5) ◽  
pp. 233-250 ◽  
Author(s):  
Michio TAGIRI ◽  
Shingo TAKIGUCHI ◽  
Chika ISHIDA ◽  
Takaaki NOGUCHI ◽  
Makoto KIMURA ◽  
...  
Keyword(s):  
Tien Shan ◽  
Metamorphic Rocks ◽  
Upper Crust ◽  
T Path

scholarly journals Neotectonic activity and paleoseismological analysis in Eastern of Antioquia, in the vicinity of Medellin city - Colombia

2015 ◽  
pp. 5-19
Author(s):  
Albeiro De Jesús Rendón-Rivera ◽  
John Jairo Gallego-Montoya ◽  
Jenny Paola Jaramillo-Rendón ◽  
Adrián González-Patiño ◽  
José Humberto Caballero-Acosta ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Age Of Onset ◽  
Active Faults ◽  
Seismic Hazard Assessment ◽  
Seismic Events ◽  
Small Surface ◽  
Neotectonic Activity ◽  
Neotectonic Deformation ◽  
Alluvial Terraces ◽  
Prehistoric Earthquakes

The aim of this investigation was the paleoseismological characterization of eastern Antioquia, using trenches analysis and detailed study of indicators of neotectonic activity, some of which had been reported in previous seismic hazard assessment studies of the Aburra Valley.Through techniques of neotectonic, paleoseismology and also age correlation of Quaternary deposits obtained by several authors, it was found at Alcaravanes site (Marinilla Town), evidences of three seismic events with magnitudes Mw 6.4, 6.6 and 6.5 which displaced recent deposits with maximum ages of 440,000, 37,000 and 8,000 years respectively. Likewise, two prehistoric earthquakes, both with magnitude Mw 6.5 were recognized at the Hamburgo site (Guarne Town), dated between 880,000 and 37,000 years respectively, which proves the existence and activity of La Mosca fault. Finally, the Manantiales site (Rionegro Town) revealed a couple of seismic events with magnitude Mw 6.7 and 6.6 that displaced alluvial terraces in Rio Negro basin with a maximum age of onset of neotectonic deformation of 880,000 years.Latest neotectonic findings change the perspective of seismic hazard in Medellin city and surroundings. Prehistoric earthquakes have occurred in the last million years and created small surface rupture and faulting not related with active mountain fronts. Furthermore, the evidence shows obliterated active faults and efficiency of erosion factors in modeling relief and alluvial fill in the basins of Rionegro Erosion Surface.

Late Paleozoic subductional and collisional igneous complexes in the Naryn segment of the Middle Tien Shan (Kyrgyzstan)

2009 ◽  
Vol 427 (1) ◽  
pp. 760-763 ◽  
Author(s):  
D. V. Alekseev ◽  
K. E. Degtyarev ◽  
A. B. Kotov ◽  
E. B. Sal’nikova ◽  
A. A. Tret’yakov ◽  
...  
Keyword(s):  
Tien Shan ◽  
Late Paleozoic ◽  
Igneous Complexes

COSEISMIQ: First results of high resolution imaging of the shallow crust and relocation of induced seismicity in the Hengill area, Iceland

2020 ◽  
Author(s):  
Anne Obermann ◽  
Pilar Sánchez-Pastor ◽  
Alejandro Duran ◽  
Tobias Diehl ◽  
Vala Hjörleifsdóttir ◽  
...  
Keyword(s):  
High Resolution ◽  
Induced Seismicity ◽  
Seismic Velocity ◽  
Active Faults ◽  
Seismic Events ◽  
Volcanic Complex ◽  
High Resolution Imaging ◽  
First Results ◽  
Resolution Imaging ◽  
Shallow Crust

<p>For the future development of deep geothermal energy exploitation in Europe, large magnitude induced seismic events are an obstacle. On the other hand, the analysis of induced microseismicity allows to obtain the spatial distribution of fractures within the reservoir, which can help, not only to identify active faults that may trigger large induced seismic events, but also to optimize hydraulic stimulation operations and to locate the regions with higher permeability, enhancing energy production. The project COSEISMIQ (COntrol SEISmicity and Manage Induced) integrates seismic monitoring and imaging techniques, geomechanical models and risk analysis methods with the ultimate goal of implementing innovative tools for the management of the risks posed by induced seismicity and demonstrate their usefulness in a commercial scale application in Iceland.</p><p>Our demonstration site is the Hengill region in Iceland. The Hengill volcanic complex is located in SW Iceland on the plate boundary between the North American and Eurasian plates. In this region, the two largest geothermal power plants of Iceland are currently in operation, the Nesjavellir (120MW electricity) and the Hellisheidi (300MW electricity) power stations. In October 2018, we densified the permanent seismic network run by ISOR and IMO in this area (14 stations) with 23 broadband seismic stations.</p><p>We present the project and show first results from high resolution imaging of the shallow crust with ambient seismic noise, as well as first results from the relocated seismic events. The ambient noise imaging highlights an area of low seismic velocity close to the Þingvallavatn Lake, characteristic for the presence of supercritical fluids. The main geothermal production area is located as well in a low velocity zone that reaches 200 meters depth below Hellisheidi and around 700 meters below Nesjavellir.</p><p> </p>

scholarly journals Features of the manifestation of lunar-solar tides in the electromagnetic parameters of the active fault zones of the Tien Shan

2020 ◽  
Vol 196 ◽  
pp. 03003
Author(s):  
Elena Bataleva
Keyword(s):  
Electromagnetic Field ◽  
Cross Correlation ◽  
Active Fault ◽  
Active Faults ◽  
Temporal Variations ◽  
Fault Zones ◽  
Tien Shan ◽  
Tectonic Activity ◽  
Electromagnetic Parameters ◽  
Fault Structures

The results of monitoring studies of the electromagnetic parameters of active fault structures on the territory of the Bishkek geodynamic proving ground are shown. The temporal variations of the electromagnetic field on several active faults of the Earth’s crust, characterized by different tectonic activity, are analyzed in comparison with the variations of lunar-solar tides. It was found that in the overwhelming majority of cases, the correlation dependences are most clearly manifested in changes in the real and imaginary parts of additional impedances than the main ones. Analysis of the cross-correlation function indicates that the reason for the change in the parameters of the electromagnetic field can be lunar-solar tides.

scholarly journals Correlation of the state of crustal stresses, seismicity and landslide activity (Fergana basin, Tien Shan)

2019 ◽  
Vol 10 (4) ◽  
pp. 995-1009
Author(s):  
Z. A. Kalmet’eva ◽  
B. D. Moldobekov ◽  
U. A. Abdybachaev
Keyword(s):  
Internal Structure ◽  
The State ◽  
Tien Shan ◽  
Stress Axis ◽  
Hazard Mapping ◽  
Upper Crust ◽  
Strong Earthquakes ◽  
Landslide Activity ◽  
Crustal Stresses ◽  
Local Stresses

The impacts of seismicity on the landslide activity in Kyrgyzstan have been in the focus of our study since 2010 [Kalmetyeva et al., 2010]. As the study progressed [Kalmetyeva, Moldobekov, 2012, 2013; Kalmetyeva et al., 2013, 2014], the initial problem statement has been revised as follows: do earthquake influence the occurrence of land‐ slides, and, if so, what is the mechanism of this influence. This paper presents the results of detailed analysis of the distribution of earthquakes and landslides in space and time in correlation with focal mechanisms (azimuth and plunge of the principal compression stress axis) of earthquakes occurred in the Fergana basin and its mountainous frame. These are grounds to conclude that the landslide activity is mainly influenced by the response of the internal structure of the upper crust to local stresses. The mechanism of influence of strong earthquakes on the landslide activity is redistribution of local stresses, which results from partial release of regional stresses due to rupturing in the source zones of strong earthquakes. Using this concept of the landslide activity, a methodology of landslide‐hazard mapping is the goal of our future studies aimed at the following: (1) zoning of the study area with respect to the features of the internal structure of the upper crust, (2) geological, geophysical and seismological studies of the state of stresses in the study area, (3) instrumental monitoring of landslides movements in the zones that differ in the structure of the upper crust, and (4) analysis of preparation and consequences of past strong earthquakes that took place in the study area in comparison with the landslide activity.

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