scholarly journals Similarities between recent seismic activity and paleoseismites during the late miocene in the external Betic Chain (Spain): relationship by ‘b’ value and the fractal dimension

2003 ◽  
Vol 25 (5) ◽  
pp. 749-763 ◽  
Author(s):  
M.A Rodrı́guez Pascua ◽  
G De Vicente ◽  
J.P Calvo ◽  
R Pérez-López
Keyword(s):  
Fractal Dimension ◽  
Late Miocene ◽  
Seismic Activity ◽  
B Value

Historical and recent seismic activity in South Carolina

1972 ◽  
Vol 62 (3) ◽  
pp. 851-864 ◽  
Author(s):  
G. A. Bollinger
Keyword(s):  
South Carolina ◽  
Seismic Activity ◽  
B Value ◽  
Low Noise ◽  
The State ◽  
Seismic Zone ◽  
Recurrence Relationship ◽  
Noise Data ◽  
History Of ◽  
Felt Area

Abstract The seismic history of South Carolina is dominated by the great Charleston earthquake of August 31, 1886. In addition to having several unusual aspects (region essentially free from shocks for preceding 200 years, large felt area, dual epicenter points, “low intensity zone” in West Virginia), that intensity X event seriously perturbed the seismic regime of the area for at least the following 30 years. Of 438 earthquakes reported to have occurred in the state between 1754 and 1971, 402 have been in the Charleston-Summerville area. The remaining 36 shocks form a southeasterly-trending zone of activity that is transverse to the structural grain of the Appalachians. For the 60 shocks assigned an intensity value (1886-1971), a recurrence relationship between the number of earthquakes “N” of maximum intensity “I0” was found to be log N = 0.52-0.31 I0 for IV ≦ I0 ≦ VIII. This corresponds to a “b” value of 0.5 ± 0.1 in log N versus M relationship assuming M = 1 + (2/3)I0. These data suggest a frequency of seismic activity comparable to that reported for the New Madrid seismic zone. Three months of microearthquake monitoring in the Charleston area during the summer of 1971 yielded 505 hr of low-noise data. Sixty-one earthquakes, primarily in swarm occurrence, were recorded. An h value of 1.8 ± 0.5 was determined for these microshock events. This value is similar to that previously observed for a swarm sequence in New Jersey. Four shocks occurred in the state during 1971. Three of these events (May 19, July 31, August 11) were in the central part of the state near Orangeburg, while the third event (July 13) was near Seneca in northwestern South Carolina. All three events had 3.0 < ML < 4.0. Similar episodes of three or four shocks in 1 year happened in 1956 and again in 1965. The Orangeburg area had, according to historical data, been previously free of earthquake epicenters.

Detection of ULF Geomagnetic Anomalies Associated to Seismic Activity Using EMD Method and Fractal Dimension Theory

2017 ◽  
Vol 15 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Juan Pablo Amezquita Sanchez ◽  
Omar Chavez Alegria ◽  
Martin Valtierra Rodriguez ◽  
Jose Antonio Lopez Cruz Abeyro ◽  
Jesus Roberto Millan Almaraz ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Seismic Activity ◽  
Dimension Theory ◽  
Emd Method ◽  
Geomagnetic Anomalies

Fractal dimension and b-value mapping in the Andaman-Sumatra subduction zone

2010 ◽  
Vol 57 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Sohini Roy ◽  
Uma Ghosh ◽  
Sugata Hazra ◽  
J. R. Kayal
Keyword(s):  
Fractal Dimension ◽  
Subduction Zone ◽  
B Value

scholarly journals Fractal Characterization of Earthquake occurrences in Nigeria

2019 ◽  
Vol 1 ◽  
pp. 281-287
Author(s):  
N N Abdulsalam ◽  
O Ologe
Keyword(s):  
Fractal Dimension ◽  
Active Zone ◽  
Hazard Analysis ◽  
B Value ◽  
Google Earth ◽  
Counting Method ◽  
Microsoft Word ◽  
Box Counting ◽  
Box Counting Method

Fractal characterization of Earthquake occurrences in Nigeria was carried out in order to know the b-value of tremor occurrences in the country. This will help in hazard analysis and research in the geological and geophysical structures of Nigeria. The method used in determining the b-value is the box counting method, but for simplicity, we used circle. The areas that are tremor prone were posted on a digitized Nigeria map using Google earth and Surfer 7.0 software. The computation with the box counting method was performed with picked radius of the circle from 50km - 350km and the average number of points that falls within each circle were recorded. The graph of log r (the logarithms of radius of circle or scale) against log <N> (logarithms of average number of points) was plotted using grapher and excels Microsoft word and the slope of the graph was determined. The determined slope gave the fractal dimension and the b-value was thus calculated. In this work, a b-value of 0.6 was obtained indicating that Nigeria falls within seismically less active zone.

scholarly journals LONG TEMPORAL VARIATION OF SEISMIC PARAMETERS FOR SEISMIC PATTERNS IDENTIFICATION IN GREECE

2004 ◽  
Vol 36 (3) ◽  
pp. 1362
Author(s):  
I. Baskoutas ◽  
G. Panopoulou ◽  
G. Papadopoulos
Keyword(s):  
Temporal Variation ◽  
Seismic Activity ◽  
Time Window ◽  
Energy Parameter ◽  
Aegean Sea ◽  
B Value ◽  
Seismogenic Zone ◽  
Earthquake Catalog ◽  
Estimation Model ◽  
Seismic Parameters

A new approach of detailed spatio-temporal variation analysis of seismic data is proposed by means of FastBEE (Fast estimation of Big Expected Earthquake) aiming at the regional monitoring of seismic activity for premonitory seismic patterns identification. For the investigation of temporal variation, a set of seismic parameters is used, like the logarithm of the number of earthquakes logN, estimates of 6-value obtained by the maximum likelihood estimation model, time clustering of seismic activity AR(t) and of energy released EM, since they can be considered as precursory seismological indicators. Earthquake catalog data, used in this approach, were elaborated in order to construct the time series for each parameter within a time window, large enough, as to guarantee statistical meaningful result. The Hellenic trench-arc region under investigation is chosen in the basis of its seismotectonic characteristics, in relation to the spatial extent of the seismogenic zone. The tools were tested, for long temporal variation features in the Ionian Islands Sea and the North Aegean Sea regions and its successful applicability is presented. The rise of irregularity, along these temporal profiles, was formulated in specific quantitative premonitory seismic pattern. In most of the cases, FastBEE premonitory pattern found shows significant changes from the background values of each parameter. Parameter logN shows a valley form curve, which start to increase before the expected earthquake occurrence, as well as the energy parameter E273, while b-value temporal estimates are forming a mountain shape curve, before the occurrence of a big earthquake. Instead, parameter ÙR(t) present a rapid fluctuation, without any kind of premonitory character

scholarly journals METHODOLOGICAL APPROACHES TO DETERMINING THE STATE OF BLOCK SEISMOGENIC MEDIUM ON THE EXAMPLE OF THE 2008-2011 SEISMIC ACTIVATION IN THE CENTRAL PART OF THE BAIKAL RIFT

2019 ◽  
pp. 4-13
Author(s):  
P. G. Dyadkov ◽  
Y. M. Romanenko ◽  
M. P. Kozlova ◽  
L. V. Tsibizov ◽  
A. A. Duchkova
Keyword(s):  
Energy Release ◽  
Seismic Activity ◽  
Seismic Energy ◽  
B Value ◽  
The State ◽  
Joint Analysis ◽  
Block Medium ◽  
Seismic Regime ◽  
Methodological Approaches ◽  
Epicentral Region

Based on the joint analysis of the seismic regime parameters, such as anomalies of seismic energy release, b-value, seismic activity A10, approaches to assess the state of the block-seismic medium are proposed. The method validation was done for the example of preparation and development of seismic activity in 2008-2011 in the Central part of the Baikal rift, during which there were 2 strong M5.3 earthquakes. It was found that within 2 years before the strong Maximihinskoye Earthquake of 2008 in the Earth's crust of the epicentral region there is a transformation from softening to strengthening (consolidation) of the block medium. At the same time, in the neighboring region (the area of the Svyatoy Nos Peninsula), the opposite nature of the changes is observed.

Seismotectonic maps of southwest Asia region comprising Eastern Turkey, Caucasus, Persian Plateau, Afghanistan and Hindukush

1974 ◽  
Vol 64 (3-1) ◽  
pp. 657-669 ◽  
Author(s):  
K. L. Kaila ◽  
N. Madhava Rao ◽  
Hari Narain
Keyword(s):  
Fracture Zone ◽  
Seismic Activity ◽  
B Value ◽  
Southwest Asia ◽  
The Caucasus ◽  
Regression Curves ◽  
A Value ◽  
Thrust Zone ◽  
Kopet Dagh ◽  
Regional Tectonics

abstract Three seismic activity maps, the A-value map, the b-value map and the returnperiod map for earthquakes with magnitude 6 and above, have been prepared for the southwest Asia region using the Kaila and Narain (1971) method, and the same are compared with regional tectonics. For the preparation of these maps, a modified relation A = 6.36b - 1.00 has been used instead of the earlier relation where A and b are constants in the cumulative regression curve represented by log N = A − bM. The A-value seismicity map reveals that the Southwest Asia region consists of a number of seismic high zones such as the Caucasus-Abul Samsar high, the Zagros high, the Shahrud-Doruneh high and the Hindukush-West Pakistan high. The Caucasus-Abul Samsar seismic high shows two superimposed trends, one NW-SE which is consistent with the Caucasus tectonic trend and the other NE-SW which is parallel to the Abul Samsar fracture zone. The Zagros seismic high runs in the NW-SE direction almost parallel to the Zagros thrust zone with diversions to the northeast at the two ends. High seismic activity is revealed in the Zagros foothills area rather than the thrust-zone. The Shahrud-Doruneh high shows a NW-SE trend parallel to Kopet Dagh, and, toward the west, it bends down aligning itself almost parallel to the Elburz mountains, thus indicating the possibility of a connection between this high and the Zagros high. The Hindukush-West Pakistan high runs in the NNE-SSW direction consistent with the tectonic trends in this area, indicating the highest seismic activity near the Yasman fracture zone. The b-value seismicity map also reveals the same seismic features as brought out by the A-value map. The b-values obtained by this new method over various regions of southwest Asia agree fairly well with those reported by other workers obtained from earthquake regression curves. The return-period map further brings out the zones of high and low seismic activity which are quite consistent with the A-and the b-value maps, and the regional tectonics.

SCALING LAWS OF SEISMIC EVENTS — A MODEL WITH FRACTAL GEOMETRY

Fractals ◽  
1999 ◽  
Vol 07 (04) ◽  
pp. 341-351
Author(s):  
C. GODANO ◽  
M. L. ALONZO
Keyword(s):  
Fractal Dimension ◽  
Fractal Geometry ◽  
Scaling Laws ◽  
B Value ◽  
Seismic Events ◽  
Magnitude Distribution ◽  
Transitional State ◽  
Contact Points ◽  
Omori Law ◽  
Local Fluctuations

Most models of earthquakes attempt to reproduce the observed scaling laws of seismic events: the Gutenberg-Richter frequency magnitude distribution, but not the Omori law for aftershocks and the multifractal distribution of hypocenters location. Many of these models are based on the idea of Self-Organized Criticality (SOC). These are dynamic systems which organize themselves into a transitional state and can reproduce the Gutenberg-Richter distribution, but generally do not reproduce the space-time distribution. Here, we suggest a model based on a fractal geometry: the two sides of a fault are modeled by means of a fractal surface. As a first step, one of them is slipped of a random amount with periodic boundary conditions, then new contact points between the surfaces are found. The area surrounded by these points is assumed to be proportional to the area of the earthquake. The size distribution of events is in good agreement with the observed Gutenberg-Richter law and the local fluctuations of the b value are explained in terms of variations of the fractal dimension of the surface. Also the multifractal distribution of earthquakes in space is well-reproduced with global properties not depending on the fractal dimension of the surface. However, we are not able to obtain something similar to the Omori law simply because we do not control the time evolution of the model.

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