Geological Investigations of Late and Post Glacial Earthquake Activity in Scotland

1989 ◽  
pp. 175-194 ◽  
Author(s):  
Colin A. Davenport ◽  
Philip S. Ringrose ◽  
Amfried Becker ◽  
Paul Hancock ◽  
Clark Fenton
Keyword(s):  
Earthquake Activity

scholarly journals Long Short-Term Memory Networks for Pattern Recognition of Synthetical Complete Earthquake Catalog

2021 ◽  
Vol 13 (9) ◽  
pp. 4905
Author(s):  
Chen Cao ◽  
Xiangbin Wu ◽  
Lizhi Yang ◽  
Qian Zhang ◽  
Xianying Wang ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Short Term Memory ◽  
Three Dimensional ◽  
Earthquake Risk ◽  
Earthquake Activity ◽  
Earthquake Catalog ◽  
Short Term ◽  
Term Memory ◽  
Earthquake Migration ◽  
Long Short Term Memory

Exploring the spatiotemporal distribution of earthquake activity, especially earthquake migration of fault systems, can greatly to understand the basic mechanics of earthquakes and the assessment of earthquake risk. By establishing a three-dimensional strike-slip fault model, to derive the stress response and fault slip along the fault under regional stress conditions. Our study helps to create a long-term, complete earthquake catalog. We modelled Long-Short Term Memory (LSTM) networks for pattern recognition of the synthetical earthquake catalog. The performance of the models was compared using the mean-square error (MSE). Our results showed clearly the application of LSTM showed a meaningful result of 0.08% in the MSE values. Our best model can predict the time and magnitude of the earthquakes with a magnitude greater than Mw = 6.5 with a similar clustering period. These results showed conclusively that applying LSTM in a spatiotemporal series prediction provides a potential application in the study of earthquake mechanics and forecasting of major earthquake events.

The Western Limit of Iapetan Rifting in the Eastern United States: A New Assessment

2020 ◽  
Vol 91 (6) ◽  
pp. 3483-3495
Author(s):  
Christine A. Powell ◽  
William A. Thomas ◽  
Robert D. Hatcher
Keyword(s):  
United States ◽  
Seismic Hazard ◽  
Atlantic Coastal Plain ◽  
Hazard Evaluation ◽  
Earthquake Activity ◽  
Blue Ridge ◽  
Mantle Structure ◽  
Eastern United States ◽  
Appalachian Plateau ◽  
Lithospheric Thickness

Abstract Specifying the extent and location of rifted, crystalline Precambrian crust in the eastern United States is important for seismic hazard evaluation and for models that relate upper-mantle structure to ancient tectonic features and ongoing tectonism. As currently depicted in the National Seismic Hazard Maps (NSHM), the western limit of Iapetan rifted crust is beneath the Appalachian plateau physiographic province, west of the Valley and Ridge province. New estimates of crustal thickness using EarthScope Transportable Array and other data do not support the presence of rifted crust beneath the Blue Ridge, Valley and Ridge, and Appalachian plateau physiographic provinces. Crustal thicknesses exceed 45 km throughout most of this region. The crust thins to the southeast beneath the southeastern part of the Piedmont physiographic province and is only 36 km thick near the edge of the Atlantic coastal plain. We suggest that the western limit of Iapetan rift-extended crust is east of the Blue Ridge province and is associated with the prominent Appalachian gravity gradient. This location coincides with palinspastic reconstructions based on geologic data for the Iapetan rifted margin. Recognition of thick crust beneath the Blue Ridge and Valley and Ridge provinces, unextended by Iapetan rifting, will support more robust modeling of the effects of mantle structure (such as delamination and abrupt changes in lithospheric thickness) on ongoing tectonism and earthquake activity in the eastern United States and will provide more accurate seismotectonic zonation in the NSHM.

Earthquake Hazard Estimation in Areas of Low Historical Seismicity: A Focus on the Northern Rio Grande Rift, Colorado and New Mexico

1990 ◽  
Vol 6 (4) ◽  
pp. 657-680 ◽  
Author(s):  
Charles E. Glass
Keyword(s):  
New Mexico ◽  
Gaussian Model ◽  
Rio Grande ◽  
Earthquake Hazard ◽  
Weibull Model ◽  
Historical Seismicity ◽  
Rio Grande Rift ◽  
Earthquake Activity ◽  
Sangre De Cristo ◽  
Northern Rio Grande

Estimates of the probability of future earthquake activity are difficult to make in areas where historical seismicity may be low or absent, but where young fault scarps attest to recent or ongoing tectonism. Three non-Poisson models, a Weibull model, a Gaussian model and a lognormal model, are used to estimate the earthquake hazard for one such area, the northern Rio Grande Rift. This portion of the Rio Grande Rift displays numerous Holocene faults attesting to ongoing tectonism, but displays essentially no historical seismicity. The earthquake hazard for the Sangre de Cristo fault zone from Taos, New Mexico to Salida, Colorado calculated using these models is remarkably consistent (probability of at least one Mo = 7 earthquake in the next 50 years ∼ 2.5 × 10−3), with increased hazard for the Sangre de Cristo fault in north San Luis Valley (∼5.0×10−3) and near Taos (∼1.0×10−2) due to the long holding times along these segments.

Strong earthquake activity influenced by solar flare intensity

2021 ◽  
Author(s):  
Gerald Duma
Keyword(s):  
Solar Flares ◽  
Strong Earthquake ◽  
Temporal Variations ◽  
Seasonal Effect ◽  
Earthquake Activity ◽  
Strong Earthquakes ◽  
International Service ◽  
Earthquake Frequency ◽  
Magnetic Index ◽  
Magnetic Disturbances

<p>Based on the comprehensive earthquake catalogue USGS ( HYPERLINK<span>  </span>https://earthquake.usgs.gov) the paper demonstrates that strong earthquake activity, seismic events with M≥6, exhibits a seasonal trend. This feature is the result of<span>  </span>analyses of earthquake data for the N- and S- Earth Hemisphere in period 2010-2019. It can be shown also for single earthquake prone regions as well, like Japan, Eurasia, S-America.</p><p>Any seasonal effect suggests an external influence. In that regard, one can think also of a solar-terrestrial effect, that is suggested already in several studies (e.g<span>  </span>M.Tavares, A.Azevedo, 2011; D.A.E. Vares, M.A.Persinger,2014; G.Duma, 2019). This assumption leads to the question: Which dynamic process can cause a trigger effect for strong earthquakes in the Earth's lithosphere.</p><p>In this study the intensity of solar flares and the resulting radiation, the solar wind, towards the Earth was taken into account. An appropriate parameter which has been regularity measured and reported for many decades and which reflects the intensity of solar radiation is the magnetic index Kp. It is measured at numerous geomagnetic observatories and describes the magnetic disturbances in nT within 3 hour intervals, respectively. Averages of all the measured 3-hour values are then published as Kp, therefore considered a planetary parameter (International Service of Geomagnetic Indices ISGI,France).</p><p>The temporal variations of strong earthquake activity over 10 years and their energy release was compared with the above mentioned index Kp. Actually, a distinct correlation between the two quantities, Kp and earthquake frequency, resulted in cases of different regions as well as globally. Another essential result of the study is that maxima of Kp preceed those of earthquake activity by about 60 to 80 days in most cases. The mechanism has not yet been modeled satisfactorily.</p>

Wavelet analysis of the temporal-spatial distribution in the Eurasia seismic belt

2017 ◽  
Vol 15 (03) ◽  
pp. 1750018 ◽  
Author(s):  
Wenfeng Zheng ◽  
Xiaolu Li ◽  
Lirong Yin ◽  
Zhengtong Yin ◽  
Bo Yang ◽  
...  
Keyword(s):  
Fault Zone ◽  
Compact Support ◽  
Large Scale ◽  
Temporal Distribution ◽  
Seismic Energy ◽  
Research Area ◽  
Earthquake Activity ◽  
Seismic Zone ◽  
Seismic Belt ◽  
Earthquake Fault

Due to the growing frequency of earthquakes, safeties of human lives and properties are facing serious threats. However, the research in the field of spatial-temporal distribution of earthquake is quite a few. In this paper, we use wavelet model to analyze the spatial-temporal distribution of earthquakes. Because the spatial-temporal distribution of earthquake activity is closely related to the distribution of the earthquake fault zone, we analyze large-scale earthquake clusters by selecting the Eurasia seismic belt and the surrounding region as the research area. From the perspective of the time domain, the results show that the seismic energy of the earthquake fault zone presences compact support or similar compact support distribution, suggesting that the seismic zone exists a relatively quiet period and active stage. This indicate that the seismic zone is periodical. The period of strong earthquakes above normal and less than normal is different by time changes. The cycles of earthquakes are different due to different regions and different geological and geographical environment.

Tectonic implications of seismic activity recorded by the northern Ontario seismograph network

1989 ◽  
Vol 26 (2) ◽  
pp. 376-386 ◽  
Author(s):  
R. J. Wetmiller ◽  
M. G. Cajka
Keyword(s):  
Horizontal Stress ◽  
Seismic Profile ◽  
Management Program ◽  
Earthquake Activity ◽  
Seismic Velocities ◽  
Northern Ontario ◽  
Focal Mechanism Solutions ◽  
National Networks ◽  
Nuclear Fuel Waste ◽  
Seismograph Network

The northern Ontario seismograph network, which has operated under the Canadian Nuclear Fuel Waste Management Program since 1982, has provided valuable data to supplement those recorded by the Canadian national networks on earthquake activity, rockburst activity, the distribution of regional seismic velocities, and the contemporary stress field in northern Ontario. The combined networks recorded the largest earthquake known in northwestern Ontario, M 3.9 near Sioux Lookout on February 11, 1984, and many smaller earthquakes in northeastern Ontario. Focal mechanism solutions of these and older events showed high horizontal stress and thrust faulting to be the dominant features of the contemporary tectonics of northern Ontario. The zone of more intense earthquake activity in western Quebec appeared to extend northwestward into the Kapuskasing area of northeastern Ontario, where an area of persistent microearthquake activity had been identified by a seismograph station near Kapuskasing.Controlled explosions of the 1984 Kapuskasing Uplift seismic profile experiment recorded on the northern Ontario seismograph network showed the presence of anomalously high LG velocities in northeastern Ontario (3.65 km/s) that when properly taken into account reduced the mislocation errors of well-recorded seismic events by 50% on average.

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