scholarly journals Parageneses of fractures in large fault zones of West Transbaikalia

2018 ◽  
Vol 9 (3) ◽  
pp. 889-908
Author(s):  
A. V. Cheremnykh
Keyword(s):  
Quantitative Analysis ◽  
Fault Zones ◽  
Strike Slip ◽  
Focal Mechanisms ◽  
Rock Fracturing ◽  
Study Region ◽  
Tectonic Development ◽  
Paleoseismic Dislocations ◽  
The Right ◽  
Cenozoic Sediments

Our study was focused on the parageneses of heterogeneous fractures in the large fault zones of West Transbaikalia,Russia. We reconstructed the latest deformation in the fault zones of Transbaikalia, within which paleoseismic dislocations are known and M 4.7 earthquakes take place. To obtain statistically justified solutions on the kinematic types of the largest faults ofWest Transbaikalia, we collected the required data and conducted the structural and paragenetic analysis of the fractures in the study area. In the Chikoi-Ingoda, Khilok, North Tugnui andNorth Zaganfault zones, we created a network of 54 observation points and measured more than 5500 details of local fractures and faults. Recorded were the observed slickensides, the displacements of markers, and other details of rock fracturing. Based on the analysis results, we calculated a ratio of heterochronous dynamic settings for formation of the observed fault group. It shows that NW-SE-trending extension and compression are dominant in the study region. The parageneses of E-NE-striking faults, i.e. regional faults longitudinal to the depressions ofWest Transbaikalia, are abundant in the studied fault zones and generally observed in heterochronous formations, including the Cenozoic sediments. This fact, along with the focal mechanisms of the recently recorded earthquakes, suggests that these faults are young. Besides, in the Tugnui basin and the area southeast of the Chikoy depression, the right-lateral strike-slip setting was reconstructed for E-NE-trending faults. Our study pioneers in the quantitative analysis of the fault parageneses ofWest Transbaikalia. Considering the development of the network of large faults in the study area, we reconstructed the main stages and the kinematic types of the second-order fractures that constitute the internal structure of the studied fault zones at each stage of their tectonic development. 

Seismic doublets and a complex seismic sequence controlled by the rotation of the Juan Fernández microplate

2021 ◽  
Author(s):  
Simone Cesca ◽  
Carla Valenzuela Malebrán ◽  
José Ángel López-Comino ◽  
Timothy Davis ◽  
Carlos Tassara ◽  
...  
Keyword(s):  
Source Parameters ◽  
Strike Slip ◽  
Focal Mechanisms ◽  
Joint Analysis ◽  
Seismic Sequence ◽  
Local Data ◽  
Study Region ◽  
Coulomb Stress Changes ◽  
Earthquake Source Parameters ◽  
Stress Changes

<p> A complex seismic sequence took place in 2014 at the Juan Fernández microplate, a small microplate located between Pacific, Nazca and Antarctica plates. Despite the remoteness of the study region and the lack of local data, we were able to resolve earthquake source parameters and to reconstruct the complex seismic sequence, by using modern waveform-based seismological techniques. The sequence started with an exceptional Mw 7.1-6.7 thrust – strike slip earthquake doublet, the first subevent being the largest earthquake ever recorded in the region and one of the few rare thrust earthquakes in a region otherwise characterized by normal faulting and strike slip earthquakes. The joint analysis of seismicity and focal mechanisms suggest the activation of E-W and NE-SW faults or of an internal curved pseudofault, which is formed in response to the microplate rotation, with alternation of thrust and strike-slip earthquakes. Seismicity migrated Northward in its final phase, towards the microplate edge, where a second doublet with uneven focal mechanisms occurred. The sequence rupture kinematics is well explained by Coulomb stress changes imparted by the first subevent. Our analysis show that compressional stresses, which have been mapped at the northern boundary of the microplate, but never accompanied by large thrust earthquakes, can be accommodated by the rare occurrence of large, impulsive, shallow thrust earthquakes, with a considerable tsunamigenic potential.</p>

Locations and focal mechanisms of recent microearthquakes and tectonics of Livermore Valley, California

1982 ◽  
Vol 72 (3) ◽  
pp. 821-840
Author(s):  
Fred E. Followill ◽  
Joseph M. Mills
Keyword(s):  
Linear Trend ◽  
Source Region ◽  
Velocity Model ◽  
Strike Slip ◽  
Focal Mechanisms ◽  
Fault System ◽  
Lateral Velocity ◽  
Thrust Faulting ◽  
Northern Regions ◽  
The Right

abstract Over 100 well-recorded microearthquakes (local magnitude less than 3), which occurred between January and September 1980, have been relocated, and focal mechanisms have been estimated for six regions of recent seismic activity for the Livermore Valley. Each of these microearthquakes had a minimum of 10 stations distributed in at least three quadrants around the epicenter. Data from these microearthquakes were combined with data from three USGS refraction experiments and used to develop a velocity model for Livermore Valley. Using this model, together with source region and station corrections to compensate for lateral velocity variations in the upper crust, we recalculated the locations and focal mechanisms. Comparing the results from these regions, we found differences in focal depths, patterns of epicenter locations, and focal mechanisms. Focal depths in the northern regions were usually between 5 and 11 km. These were slightly greater than focal depths (2 to 8 km) in the southern regions. The pattern of strike-slip focal mechanisms with P axes trending NNE and the linear trend of epicenters along the right-lateral strike-slip Greenville fault system in the northern regions is in contrast with the pattern of a mixture of focal mechanisms in southern regions (which includes about one-third with thrust-type mechanisms where the T axis is nearer vertical than horizontal). In the southern regions, there is some indication of short offset (en echelon) segments and an absence of the extended linear trend found in the northern regions. We speculate that this more diffuse pattern of locations and focal mechanisms in the southern regions of the valley results from general north-south compressional tectonics with both strikeslip and thrust faulting occurring in a localized zone of deformation between the Livermore Valley block and the Diablo Range block to the south.

Acadian strike-slip tectonics in the Gaspé region, Quebec Appalachians

1989 ◽  
Vol 26 (9) ◽  
pp. 1764-1777 ◽  
Author(s):  
Michel Malo ◽  
Jacques Béland
Keyword(s):  
Middle Devonian ◽  
High Strain ◽  
Structural Features ◽  
Fault Zones ◽  
Strike Slip ◽  
Structural Units ◽  
Middle Ordovician ◽  
Southern Margin ◽  
Intense Deformation ◽  
Dextral Strike Slip

At the southern margin of the Cambro-Ordovician Humber Zone in the Quebec Appalachians, on Gaspé Peninsula, three structural units of Middle Ordovician to Middle Devonian cover rocks of the Gaspé Belt are in large part bounded by long, straight longitudinal faults. In one of these units, the Aroostook–Percé anticlinorium, several structural features, which can be ascribed to Acadian deformation, are controlled by three subparallel, dextral, strike-slip longitudinal faults: Grande Rivière, Grand Pabos, and Rivière Garin. These faults follow bands of intense deformation, contrasting with the mildly to moderately deformed intervals that separate them.Most of the structural features observed – rotated oblique folds and cleavage, subsidiary Riedel and tension faults, and offsets of markers – can be integrated in a model of strike-slip tectonics that operated in ductile–brittle conditions. A late increment of deformation in the form of conjugate cleavages and minor faults is restricted to the bands of high strain. An anticlockwise transection of the synfolding cleavage in relation to the oblique hinges may be a feature of the rotational deformation.The combined dextral strike slip that can be measured within the three major longitudinal fault zones amounts to 138 km, to which can be added 17 km of ductile movement in the intervals, for a total of 155 km.

Neuropsychological Assessment of a Case of Early Right Hemiplegia: Qualitative and Quantitative Analysis

1984 ◽  
Vol 59 (3) ◽  
pp. 1007-1010 ◽  
Author(s):  
Daniela Brizzolara ◽  
Anna Maria Chilosi ◽  
Gianni Luigi De Nobili ◽  
Giovanni Ferretti
Keyword(s):  
Quantitative Analysis ◽  
Neuropsychological Assessment ◽  
Normal Development ◽  
Right Hemisphere ◽  
Qualitative And Quantitative Analysis ◽  
Qualitative And Quantitative ◽  
Perceptual Skills ◽  
Left Brain ◽  
Linguistic Functions ◽  
The Right

Evidence for normal development of linguistic but poor visuo-perceptual skills has been obtained with the neuropsychological assessment of a case of early left-brain injury. Data suggest the transfer of linguistic functions from the left to the right hemisphere at the expense of visuo-perceptual capacities for which the right hemisphere is potentially specialized.

The 2019 Ms 4.2 and 5.2 Beiliu Earthquake Sequence in South China: Complex Conjugate Strike-Slip Faulting Revealed by Rupture Directivity Analysis

2021 ◽  
Author(s):  
Xiaohui He ◽  
Hao Liang ◽  
Peizhen Zhang ◽  
Yue Wang
Keyword(s):  
South China ◽  
Source Parameters ◽  
Active Faults ◽  
Fault Zones ◽  
Strike Slip ◽  
P Wave ◽  
Complex Conjugate ◽  
South China Block ◽  
Rupture Directivity ◽  
Time Duration

Abstract The South China block has been one of the most seismically quiescent regions in China, and the geometries and activities of the Quaternary faults have remained less studied due to the limited outcrops. Thus, source parameters of small-to-moderate earthquakes are important to help reveal the location, geometry distribution, and mechanical properties of the subsurface faults and thus improve the seismic risk assessment. On 12 October 2019, two earthquakes (the Ms 4.2 foreshock and the Ms 5.2 mainshock) occurred within 2 s and are located in southern South China block, near the junction region of the large-scale northeast-trending fault zones and the less continuous northwest-trending fault zones. We determined the point-source parameters of the two events via P-wave polarity analysis and regional waveform modeling, and the resolved focal mechanisms are significantly different with the minimum 3D rotation angle of 52°. We then resolved the rupture directivity of the two events by analyzing the azimuth variation of the source time duration and found the Ms 4.2 foreshock ruptured toward north-northwest for ∼1.0 km, and the Ms 5.2 mainshock ruptured toward east-southeast (ESE) for ∼1.5 km, implying conjugate strike-slip faulting. The conjugate causative faults have not been mapped on the regional geological map, and we infer that the two faults may be associated with the northwest-trending Bama-Bobai fault zone (the Shiwo section). These active faults are optimally oriented in the present-day stress field (northwest-southeast) and thus may now be potentially accumulating elastic strain to be released in a future large earthquake.

scholarly journals Bandung’s Image as a Tourist Destination: An Application of Quantitative and Qualitative Approach

2019 ◽  
Vol 1 (01) ◽  
Author(s):  
Agustinus Februadi ◽  
Nono Wibisono ◽  
Dewi Purnamasari
Keyword(s):  
Factor Analysis ◽  
Quantitative Analysis ◽  
Quantitative Method ◽  
Qualitative Approach ◽  
Tourist Destination ◽  
Nature Tourism ◽  
Scenic Beauty ◽  
Qualitative And Quantitative ◽  
The Right ◽  
Functional Attribute

Bandung is a popular tourist destination in Indonesia and a gateway for tourists who visit destinations around greater Bandung areas. Currently, Bandung is also known as a culinary, shopping, and nature tourism destination. Past studies have measured the image of Bandung as a tourist destination. However, the measurements were done partially due to the use of quantitative method only. Thus, the results were not comprehensive. To resolve the drawbacks of the previous studies, this study used both qualitative and quantitative approaches. Data were collected from 430 domestic tourists by ways of structured and unstructured interviews in 20 different destinations in Bandung and the surrounding. Data were processed by descriptive statistical methods, factor analysis and content analysis. The results of quantitative analysis show that, in term of functional-attribute, Bandung was positively perceived as a destination characterized with natural scenic beauty, many interesting places, and various exotic foods. In terms of the psychological-attribute, Bandung was perceived as the right place for shopping and culinary tourism. The results of qualitative analysis indicate that, functionally, Bandung was a destination with natural scenic beauty, pleasant weather and provide various exotic foods. Psychologically, the tourists experienced calm and tranquil atmosphere, happiness, and comfort.

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