scholarly journals Seismicity characterization of oceanic earthquakes in the Mexican territory

2020 ◽  
Author(s):  
Quetzalcoatl Rodríguez-Pérez ◽  
Víctor Hugo Márquez-Ramírez ◽  
Francisco Ramón Zúñiga
Keyword(s):  
Normal Fault ◽  
B Value ◽  
Statistical Characteristics ◽  
P Value ◽  
Transform Faults ◽  
Frequency Distributions ◽  
Ocean Ridges ◽  
The Pacific ◽  
Stress Orientations ◽  
Clear Differentiation

Abstract. We analyzed the seismicity of oceanic earthquakes in the Pacific oceanic regime of Mexico. We used data from the earthquake catalogs of the Mexican National Service (SSN), and the International Seismological Center (ISC) from 1967 to 2017. Events were classified into two different categories: intraplate oceanic (INT), and transform faults zone and mid-ocean ridges events (TF-MOR), respectively. For each category, we determined statistical characteristics such as magnitude frequency distributions, the aftershocks decay rate, the non-extensivity parameters, and the regional stress field. We obtained b-values of 1.17, and 0.82 for the INT, and TF-MOR events, respectively. TF-MOR events also exhibit local b-value variations in the range of 0.72–1.30. TF-MOR events follow a tapered Gutenberg-Richter distribution. We also obtained a p-value of 0.67 for the 1 May 1997 (Mw = 6.9) earthquake. By analyzing the non-extensivity parameters, we obtained similar q-values in the range of 1.39–1.60 for both types of earthquakes. On the other hand, the parameter a showed a clear differentiation, being higher for TF-MOR events than for INT events. This implies that more energy is released for TF-MOR events. Stress orientations are in agreement with geodynamical models for transform faults zone and mid-ocean ridges zones. In the case of intraplate seismicity, stresses are mostly related to a normal fault regime.

scholarly journals Seismicity characterization of oceanic earthquakes in the Mexican territory

Solid Earth ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 791-806
Author(s):  
Quetzalcoatl Rodríguez-Pérez ◽  
Víctor Hugo Márquez-Ramírez ◽  
Francisco Ramón Zúñiga
Keyword(s):  
Fault Zone ◽  
Normal Fault ◽  
B Value ◽  
Statistical Characteristics ◽  
P Value ◽  
Transform Fault ◽  
Earthquake Catalogues ◽  
Frequency Distributions ◽  
Clear Differentiation ◽  
Transform Fault Zone

Abstract. We analyzed the seismicity of oceanic earthquakes in the Pacific oceanic regime of Mexico. We used data from the earthquake catalogues of the Mexican National Service (SSN) and the International Seismological Centre (ISC) from 1967 to 2017. Events were classified into two different categories: intraplate oceanic (INT) and transform fault zone and mid-ocean ridges (TF-MOR) events, respectively. For each category, we determined statistical characteristics such as magnitude frequency distributions, the aftershocks decay rate, the nonextensivity parameters, and the regional stress field. We obtained b values of 1.17 and 0.82 for the INT and TF-MOR events, respectively. TF-MOR events also exhibit local b-value variations in the range of 0.72–1.30. TF-MOR events follow a tapered Gutenberg–Richter distribution. We also obtained a p value of 0.67 for the 1 May 1997 (Mw=6.9) earthquake. By analyzing the nonextensivity parameters, we obtained similar q values in the range of 1.39–1.60 for both types of earthquakes. On the other hand, the parameter a showed a clear differentiation, being higher for TF-MOR events than for INT events. An important implication is that more energy is released for TF-MOR events than for INT events. Stress orientations are in agreement with geodynamical models for transform fault zone and mid-ocean ridge zones. In the case of intraplate seismicity, stresses are mostly related to a normal fault regime.

The 4 December 2015 Mw 7.1 Normal-Faulting Antarctic Plate Earthquake and Its Seismotectonic Implications

2020 ◽  
Vol 110 (3) ◽  
pp. 1090-1100
Author(s):  
Ronia Andrews ◽  
Kusala Rajendran ◽  
N. Purnachandra Rao
Keyword(s):  
Body Wave ◽  
Focal Depth ◽  
Normal Fault ◽  
Normal Faults ◽  
Oceanic Plate ◽  
Normal Faulting ◽  
Transform Faults ◽  
Wave Inversion ◽  
Spreading Ridges ◽  
Southeast Indian Ridge

ABSTRACT Oceanic plate seismicity is generally dominated by normal and strike-slip faulting associated with active spreading ridges and transform faults. Fossil structural fabrics inherited from spreading ridges also host earthquakes. The Indian Oceanic plate, considered quite active seismically, has hosted earthquakes both on its active and fossil fault systems. The 4 December 2015 Mw 7.1 normal-faulting earthquake, located ∼700  km south of the southeast Indian ridge in the southern Indian Ocean, is a rarity due to its location away from the ridge, lack of association with any mapped faults and its focal depth close to the 800°C isotherm. We present results of teleseismic body-wave inversion that suggest that the earthquake occurred on a north-northwest–south-southeast-striking normal fault at a depth of 34 km. The rupture propagated at 2.7  km/s with compact slip over an area of 48×48  km2 around the hypocenter. Our analysis of the background tectonics suggests that our chosen fault plane is in the same direction as the mapped normal faults on the eastern flanks of the Kerguelen plateau. We propose that these buried normal faults, possibly the relics of the ancient rifting might have been reactivated, leading to the 2015 midplate earthquake.

Seismic moment catalog of large shallow earthquakes, 1900 to 1989

1992 ◽  
Vol 82 (3) ◽  
pp. 1306-1349 ◽  
Author(s):  
Javier F. Pacheco ◽  
Lynn R. Sykes
Keyword(s):  
Seismic Moment ◽  
Subduction Zones ◽  
B Value ◽  
Reference List ◽  
Transform Faults ◽  
Shallow Earthquakes ◽  
Seismicity Rates ◽  
Chile Earthquake ◽  
The Moment ◽  
Earthquake Process

Abstract We compile a worldwide catalog of shallow (depth < 70 km) and large (Ms ≥ 7) earthquakes recorded between 1900 and 1989. The catalog is shown to be complete and uniform at the 20-sec surface-wave magnitude Ms ≥ 7.0. We base our catalog on those of Abe (1981, 1984) and Abe and Noguchi (1983a, b) for events with Ms ≥ 7.0. Those catalogs, however, are not homogeneous in seismicity rates for the entire 90-year period. We assume that global rates of seismicity are constant on a time scale of decades and most inhomogeneities arise from changes in instrumentation and/or reporting. We correct the magnitudes to produce a homogeneous catalog. The catalog is accompanied by a reference list for all the events with seismic moment determined at periods longer than 20 sec. Using these seismic moments for great and giant earthquakes and a moment-magnitude relationship for smaller events, we produce a seismic moment catalog for large earthquakes from 1900 to 1989. The catalog is used to study the distribution of moment released worldwide. Although we assumed a constant rate of seismicity on a global basis, the rate of moment release has not been constant for the 90-year period because the latter is dominated by the few largest earthquakes. We find that the seismic moment released at subduction zones during this century constitutes 90% of all the moment released by large, shallow earthquakes on a global basis. The seismic moment released in the largest event that occurred during this century, the 1960 southern Chile earthquake, represents about 30 to 45% of the total moment released from 1900 through 1989. A frequency-size distribution of earthquakes with seismic moment yields an average slope (b value) that changes from 1.04 for magnitudes between 7.0 and 7.5 to b = 1.51 for magnitudes between 7.6 and 8.0. This change in the b value is attributed to different scaling relationships between bounded (large) and unbounded (small) earthquakes. Thus, the earthquake process does have a characteristic length scale that is set by the downdip width over which rupture in earthquakes can occur. That width is typically greater for thrust events at subduction zones than for earthquakes along transform faults and other tectonic environments.

scholarly journals Hubungan Penggunaan Gadget Dengan Kemandirian Dan Kematangan Sosial Anak Pra Sekolah

2019 ◽  
Vol 6 (2) ◽  
pp. 107-118
Author(s):  
Tutik Hidayati ◽  
Yessy Nur Endah Sary ◽  
Iis Hanifah
Keyword(s):  
Preschool Children ◽  
School Children ◽  
Developmental Disorders ◽  
Negative Impact ◽  
B Value ◽  
Rank Test ◽  
P Value ◽  
Cross Sectional ◽  
Spearman Rank ◽  
Social Maturity

Child development can be done with environmental habits and the provision of stimulation to pre-school children. The use of gagdet has a large impact, both good and bad for everyone, especially for preschoolers with technological developments at this time. Preschool children with developmental disorders were 85,779 (62.02%). Besides pre-school children also experience emotional problems that have a negative impact on the development and readiness to go to school around 9.5% - 14.2% of children aged between zero to five years. The purpose of this study was to analyze the Relationship between the Use of Gadgets and the Independence and Social Maturity of Children in Putra Bangsa Kindergarten, Gading District. The research design used was cross sectional. Data collection used in this study using a questionnaire. Spearman Rank test results between the use of gagdet with independence and social maturity obtained p value 0,000 <α 0.05, then ha is accepted so that there is a relationship between the use of gagdet with independence and social maturity. has a value of 4.668 which means that independence has a 4,668 chance to change. While the social maturity variable in multiple logistic regression has an Exp (B) value of 2.545, from these results it can be explained that social maturity has an opportunity to increase by 2.545 times..   Keywords: Gadgets, Independence, Social Maturity, Preschool Children ABSTRAK   Perkembangan anak dapat dilakukan dengan kebiasaan lingkungan dan pemberian stimulasi pada anak pra sekolah. Penggunaan gagdet mempunyai dampak yang besar, baik dampak baik maupun buruk untuk semua orang, terutama bagi anak pra sekolah dengan perkembangan teknologi pada saat ini. Anak pra sekolah dengan gangguan perkembangan sebanyak 85.779 (62,02%). Selain itu anak pra sekolah juga mengalami masalah emosional yang berdampak negatif pada perkembangan dan kesiapan untuk bersekolah sekitar  9,5% - 14,2% anak berusia antara nol sampai lima tahun. Tujuan penelitian ini adalah untuk menganalisis Hubungan Penggunaan Gadget Dengan Kemandirian Dan Kematangan Sosial Anak di TK Putra Bangsa Kecamatan Gading. Desain penelitian yang digunakan adalah cross sectional.  Pengumpulan data yang digunakan pada penelitian ini menggunakan kuesioner. Hasil uji Spearman Rank  antara penggunaan gagdet dengan kemandirian dan kematangan sosial diperoleh nilai p value 0,000 < α 0,05, maka ha diterima sehingga ada hubungan antara penggunaan gagdet dengan kemandirian dan kematangan sosial.. Besarnya  nilai Exp (B) pada analisis regresi logistik kemandirian memiliki nilai 4,668 yang berarti bahwa kemandirian memiliki peluang 4,668 kali untuk berubah. Sedangkan variabel kematangan  sosial pada regresi logistik berganda memiliki nilai Exp (B) sebesar 2,545, dari hasil tersebut dapat dijelaskan bahwa kematangan  sosial memiliki peluang meningkat 2,545kali. Kata kunci: Gadget, Kemandirian, Kematangan Sosial, Anak Pra Sekolah.

3. Fracture zones and transform faults

2015 ◽  
pp. 36-52
Author(s):  
Peter Molnar
Keyword(s):  
Fracture Zones ◽  
Transform Faults ◽  
Ocean Ridges ◽  
The 1950S

‘Fracture zones and transform faults’ introduces fracture zones, huge, long linear scars in the seafloor first mapped in the 1950s, and their interpretation in terms of a new concept, transform faulting. Fracture zones are made at mid-ocean ridges, where the seafloor spreads apart. Segments of zones of spreading intersect fracture zones at right angles, along which transform faulting transfers the spreading on one spreading zone to another. As the seafloor spreads, and plates move apart at mid-ocean ridges, fracture zones grow longer. Testing this idea relied on the study of earthquakes that occurred on the transform faults, using seismographs on distant continents. This chapter introduces readers to the pertinent seismological methods by which this was achieved.

scholarly journals Source Parameter of Earthquakes in Talala, Gujarat (India): An Implication towards Seismotectonic

Proceedings ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 7
Author(s):  
Sandeep Kumar Aggarwal
Keyword(s):  
Epicentral Distance ◽  
Moment Tensor ◽  
Source Parameters ◽  
Focal Depth ◽  
B Value ◽  
Complete Sequence ◽  
P Value ◽  
Centroid Moment Tensor ◽  
North East ◽  
Lateral Plane

Talala is an excellent example of triggered neo-tectonic seismicity between two dams during a monsoon. An earthquake of Mmax 5.1 on 6 November 2007 at 21.16° N; 70.54° E, with a focal depth of 4.5 km and complete sequence, was first-time recorded on the latest broadband sensor. This found a dam/monsoon-induced earthquake preceded by 18 foreshocks of 2 ≤ Mw ≤ 4.8 within 9 h 11 minute, as well as smaller shocks that may not have been recorded because of sparse network coverage. After the deployment of local mobile observatories, aftershocks of Mw ≥ 1.0, which continued for months and subsided to background seismicity after four months, were recorded. The same kind of phenomena repeated, with Mmax 5.0 on 20 October 2011 at 21.06° N; 70.50° E, focal depth 5.5 km, which implies that the potential to generate dam/monsoon-induced seismicity took nearly four years again. These phenomena continued and the sequence was recorded by a network of 10 broadband seismographs (three in the Talala area and seven at an epicentral distance of 30 to 300 km). Centroid Moment Tensor (CMT) solutions and spectral source parameters of mainshock and aftershocks are evaluated to understand the seismotectonic of the region. The CMT depicts a major strike-slip motion along East North East-West South West with a left-lateral plane at 4.5 km depth. This indicates a sympathetic fault extension of the Son-Narmada fault. The source parameters of 400 shocks of Mw 1.0 to 5.1 found seismic moment 1011 to 1016.5 N-m, source radii 120–850 meter, and a stress drop of 0.003 to 25.43 Mpa. The b-value, p-value, fractal dimension, and slip on estimated different faults. The comparison between Talala and Koyna dam-induced source parameters tries to establish a comparison of seismicity from different parts of the world.

scholarly journals Application of the Variety-Generator Approach to Searches of Personal Names in Bibliographic Data Bases--Part 1. Microstructure of Personal Authors' Names

1974 ◽  
Vol 7 (2) ◽  
pp. 105 ◽  
Author(s):  
Dirk W. Fokker ◽  
Michael F. Lynch
Keyword(s):  
Numerical Algorithms ◽  
Statistical Characteristics ◽  
Data Bases ◽  
Frequency Distributions ◽  
Personal Names ◽  
Storage And Retrieval ◽  
Bibliographic Data ◽  
Computer Based ◽  
Data Elements ◽  
Homogeneous Data

<p class="p1">Conventional approaches to processing records of linguistic origin for storage and retrieval tend to regard the data as immutable. The data generally exhibit great variety and disparate frequency distributions, which are largely ignored and which entail either the storage of extensive lists of items or the use of complex numerical algorithms such as hash coding. The results in each case are far from ideal.</p> <p class="p1">The variety-generator approach seeks to reflect the microstructure of data elements in their description for storage and search, and takes advantage of the consistency of statistical characteristics of data elements in homogeneous data bases.</p> <p class="p1">In this paper, the application of the variety-generator approach to the description of personal author names from the INSPEC data base by means of small sets of keys is detailed. It is shown that high degrees of partitioning of names can be obtained by key-sets generated from the initial characters of surnames, fmm the terminal characters of surnames, and from the initials.</p> <p class="p1">The implications of the findings for computer-based bibliographical informationsystems are discussed.</p>

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