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1.
A. B. Baba E. E. Papadimitriou B. C. Papazachos C. A. Papaioannou B. G. Karakostas 《Pure and Applied Geophysics》2000,157(5):765-783
2.
S. J. Gibowicz 《Pure and Applied Geophysics》1998,153(1):5-20
—The values of uniformly estimated apparent stress σa and Brune’s stress drop, taken as a measure of static stress drop, from 850 seismic events, with moment magnitude ranging from ?3.6 to 3.6, induced at the Underground Research Laboratory (URL) in Canada, Western Deep Levels (WDL) gold mine in South Africa, and two coal and two copper mines in Poland, were collected to study the stress release mode in various mining environments. For this, the quantity epsilon, ?=Δσ/(σa + Δσ/2), where Δσ is the static stress drop, proposed by Zúñiga (1993) as an indicator of stress-drop mechanism was used. The events induced at the URL are characterized by low values of epsilon corresponding to a partial stress drop mechanism, whereas all the events at WDL display a frictional overshoot mechanism in which final stress reaches a lower value than that of frictional stress. The events at Polish coal and copper mines, on the other hand, are in good agreement with the well-known Orowan’s condition such that the final stress is equal to the dynamic frictional stress.¶The Brune stress drop, however, is heavily model dependent through the source radius-corner frequency relation. The Orowan’s condition for the events from the URL would be met if a constant in the source radius-corner frequency relation is equal to 1.82 ± 0.12, and for the events from WDL if it is equal to 3.92 ± 0.40, in contrast to Brune’s constant of 2.34.¶The smoothed values of epsilon displayed as a function of time, represented by the consecutive event numbers, for selected sets of events imply that the largest seismic events in a given set occur when the epsilon is low and a partial stress drop mechanism is dominant. The large events are then followed by high epsilon values when a frictional overshoot mechanism begins to dominate. 相似文献
3.
Universality of the Seismic Moment-frequency Relation 总被引:1,自引:0,他引:1
Y. Y. Kagan 《Pure and Applied Geophysics》1999,155(2-4):537-573
—We analyze the seismic moment-frequency relation in various depth ranges and for different seismic regions, using Flinn-Engdahl's regionalization of global seismicity. Three earthquake lists of centroid-moment tensor data have been used the Harvard catalog, the USGS catalog, and the Huang et al. (1997) catalog of deep earthquakes. The results confirm the universality of the β-values and the maximum moment for shallow earthquakes in continental regions, as well as at and near continental boundaries. Moreover, we show that although fluctuations in earthquake size distribution increase with depth, the β-values for earthquakes in the depth range of 0–500 km exhibit no statistically significant regional variations. The regional variations are significant only for deep events near the 660 km boundary. For declustered shallow earthquake catalogs and deeper events, we show that the worldwide β-values have the same value of 0.60 ± 0.02. This finding suggests that the β-value is a universal constant. We investigate the statistical correlations between the numbers of seismic events in different depth ranges and the correlation of the tectonic deformation rate and seismic activity (the number of earthquakes above a certain threshold level per year). The high level of these correlations suggests that seismic activity indicates tectonic deformation rate in subduction zones. Combined with the universality of the β-value, this finding implies little if any variation in maximum earthquake seismic moment among various subduction zones. If we assume that earthquakes of maximum size are similar in different depth ranges and the seismic efficiency coefficient, χ, is close to 100% for shallow seismicity, then we can estimate χ for deeper earthquakes for intermediate earthquakes χ≈ 5%, and χ≈ 1% for deep events. These results may lead to new theoretical understanding of the earthquake process and better estimates of seismic hazard. 相似文献
4.
Study on the Moment Magnitude of Small and Moderate Earthquakes Located in the Inner Mongolia Region
Based on digital seismic waveform data from Inner Mongolia Digital Seismic Network, the source spectrum parameters of 182 small and moderate earthquakes from January, 2009 to September, 2016 are derived, and the seismic moment M0 and moment magnitude MW of the earthquakes are calculated. The ML-MW relationship and the relationship between stress drop and magnitude are obtained using the linear regression method. It is clear that incorporating the moment magnitude into the seismic quick report catalog and the official earthquake catalog can enrich earthquake observation report content, thus providing better service for earthquake emergency and earthquake scientific research. 相似文献
5.
K. Koch 《Pure and Applied Geophysics》2002,159(4):759-778
6.
7.
Iranian earthquakes, a uniform catalog with moment magnitudes 总被引:3,自引:1,他引:2
Sepideh Karimiparidari Mehdi Zaré Hossein Memarian Andrzej Kijko 《Journal of Seismology》2013,17(3):897-911
A uniform earthquake catalog is an essential tool in any seismic hazard analysis. In this study, an earthquake catalog of Iran and adjacent areas was compiled, using international and national databanks. The following priorities were applied in selecting magnitude and earthquake location: (a) local catalogs were given higher priority for establishing the location of an earthquake and (b) global catalogs were preferred for determining earthquake magnitudes. Earthquakes that have occurred within the bounds between 23–42° N and 42–65° E, with a magnitude range of M W 3.5–7.9, from the third millennium BC until April 2010 were included. In an effort to avoid the “boundary effect,” since the newly compiled catalog will be mainly used for seismic hazard assessment, the study area includes the areas adjacent to Iran. The standardization of the catalog in terms of magnitude was achieved by the conversion of all types of magnitude into moment magnitude, M W, by using the orthogonal regression technique. In the newly compiled catalog, all aftershocks were detected, based on the procedure described by Gardner and Knopoff (Bull Seismol Soc Am 64:1363–1367, 1974). The seismicity parameters were calculated for the six main tectonic seismic zones of Iran, i.e., the Zagros Mountain Range, the Alborz Mountain Range, Central Iran, Kope Dagh, Azerbaijan, and Makran. 相似文献
8.
The Harvard CMT catalogue contains 481 shallow earthquakes that occurred between 1 January 1977 and 30 November 2005 within
a broad region defined by the geographical latitude from 3°S to 14°N and by the longitude from 91°E to 102°E. There are 230
events that occurred before the great earthquake of 26 December 2004. Their surface distribution is not uniform and the source
area of the 2004 great event appears as an area of seismic quiescence with a radius of about 100 km. There are 186 events
that occurred between the two great earthquakes of 26 December 2004 and 28 March 2005. Practically all of them are located
to the northwest from the great earthquake of 2005, that in turn was followed by 63 events, mostly located to the southeast.
The cumulative seismic moment from earthquakes before the occurrence of the great event of 2004 increased rather regularly
with time, with sudden increase about twenty years and two years before the occurrence of the great event. The seismic moment
of earthquakes between the two great events increased rapidly during the first ten-fifteen days, then flattened out and increased
slowly with time. After the great event of 2005 the seismic moment shows quiet increase during some 115 days, then sudden
jump, followed by very small activity till the end of our observations. From the spatial distribution of seismic moment of
earthquakes that occurred before the great event of 2004 it follows that its largest release appeared to the southeast from
the great event, around the rupture area of the great earthquake of 2005. The largest release of seismic moment from earthquakes
between the two great events is observed in the vicinity of the 2004 event and further up to the north. The seismic moment
from earthquakes that occurred after the great event of 2005 was mostly released in its vicinity and further down to the south. 相似文献
9.
Scaling relations for seismic events induced by mining 总被引:1,自引:0,他引:1
S. J. Gibowicz 《Pure and Applied Geophysics》1995,144(2):191-209
The values of seismic moment andS-wave corner frequency from 1575 seismic events induced in South African, Canadian, Polish, and German underground mines were collected to study their scaling relations. The values ofP-wave corner frequency from 649 events were also available. Seismic moments of these events range from 5*103 to 2*1015 N·m (moment magnitude is from –3.6 to 4.1), theS-wave corner frequency ranges from 0.7 to 4438 Hz, and theP-wave corner frequency is between 5 and 4010 Hz. The slope of a regression line between the logarithm ofS- andP-wave corner frequencies is equal to one, and the corner frequencies ofP waves are higher than those ofS waves on the average by about 25 percent. In studies of large and moderate earthquakes it has been found that stress drop is approximately independent of the seismic moment, which means that seismic moment is inversely proportional to the third power of corner frequency. Such a behavior was confirmed for most of the data considered here. A breakdown in the similarity betwen large and small events seems to occur for the events with moment magnitude below –2.5. The average values of seismic moment referred to the same range of corner frequency, however, are vastly different in various mining areas. 相似文献
10.
The Reviewed Event Bulletin (REB) of the International Data Center (IDC) has been used in order to investigate the seismicity of the Northwest Himalaya and its neighboring region for the time period June 1999 to March 2015 within the geographical coordinates 25–40° N latitude and 65–85° E longitude. We have used a very precisely located earthquake dataset recorded by the International Monitoring System (IMS) Network containing 7,583 events with body wave magnitudes from 2.5 to 6.3. The study area has been subdivided into six regions based on the Flinn-Engdahl (F-E) seismic and geographical regionalization scheme, which was used as the region classifications of the International Data Center catalog. The examined region includes NW India, Pakistan, Nepal, Xizang, Kashmir, and Hindukush. For each region, Magnitudes of completeness (Mc) and Gutenberg-Richter (GR) recurrence parameters (a and b values) have been estimated. The Gutenberg-Richter analysis is preceded by an overview of the seismotectonics of the study area. The obtained Mc values vary from 3.5 to 3.9. The lower value of Mc was found mainly in Xizang region whereas the higher Mc threshold is evident in Pakistan region. However, the b values vary from 1.19 to 1.48. The lowest b value is recorded in Xizang region, which is mostly related to the Main Karakoram Thrust (MKT) fault, whereas the highest b values are recorded in NW India and Kashmir regions, which are mostly related to the Main Frontal Thrust (MFT) fault. The REB for the selected period has been compared to the most renowned bulletin of global seismicity, namely that issued by the National Earthquake Information Center (NEIC) of the United States Geological Survey (USGS). A study of 4,821 events recorded by USGS in the study region indicates that about 36 % of seismic events were missed and the catalog is considered as complete for events with magnitudes ≥4.0. However, both a and b values are obviously higher than those of IMS catalog. The a and b parameters in the Gutenberg-Richter magnitude–frequency relationship have been utilized to forecast the probability of future earthquakes of different magnitudes and returned periods (recurrence intervals). 相似文献
11.
José Morales Juan V. Cantavella Flor de Lis Mancilla Lucía Lozano Daniel Stich Encarnación Herraiz José B. Martín José A. Lopez-Comino José M. Martinez-Solares 《Bulletin of Earthquake Engineering》2014,12(5):1871-1888
The Lorca 2011 seismic series was recorded by an unprecedented set of high quality on scale broadband seismograms and strong motion accelerograms. The waveforms from permanent and temporary broadband seismic networks deployed in the region by different institutions allowed to invert regional moment tensor for the fore, main and largest aftershock of the complete seismic sequence. Using double-difference algorithm we have performed a precise relocation of the seismic series, where body wave travel times from strong ground motion accelerograms were included in the data set. Regional moment tensor inversion for the three main events show similar oblique-reverse faulting regime with a northeast-southwest fault orientation. The scalar seismic moment, moment magnitude and focal depth retrieved from the inversion yield the following values for each event: \(\hbox {Mo}=6.5\times 10^{16}\) Nm (Mw = 5.2) for the mainshock, \(\hbox {Mo}= 9.6 \times 10^{15}\) Nm (Mw = 4.6) for the foreshock and \(\hbox {Mo}=7.3\times 10^{14}\) Nm (Mw = 3.9) for the large aftershock. The centroid depths range between 4 and 6 km. The double-difference relocation of the seismic series shows significant epicentral differences with the preliminary routine location. The epicentral solutions given by this relocation show a seismic sequence distributed following a NE–SW strike, subparallel to the Alhama de Murcia fault and compatible with the faulting parameters inverted from the moment tensor analysis. The hypocenters of the series generate a subvertical trend in depth distribution, being concentrated between 2 and 6 km. The depth distribution of the main events, which range from 4.6 to 5.5 km, is in good relationship with the faulting and depth parameters deduced from the moment tensor inversion technique. The regional moment tensor solutions for the three largest earthquakes, the epicentral distribution and the focal depths show good relationship with the surface geometry and tectonic regime of the Alhama de Murcia fault. The stress drop deduced for the mainshock gives a value ranging between 58 and 85 bars, which does not support the idea of a high stress drop release as a main factor contributing to the high ground acceleration recorded at Lorca. The PGA values observed at Lorca, which contributed to the high damage independently of structural deficiencies, could be generated mainly by shallowness and proximity to the seismic source together with a directivity effect in the seismic radiation. 相似文献
12.
Nader Davoudi Hamid Reza Tavakoli Mehdi Zare Abdollah Jalilian 《Acta Geophysica》2018,66(6):1359-1373
The main goal of this article is to decluster Iranian plateau seismic catalog by the epidemic-type aftershock sequence (ETAS) model and compare the results with some older methods. For this purpose, Iranian plateau bounded in 24°–42°N and 43°–66°E is subdivided into three major tectonic zones: (1) North of Iran (2) Zagros (3) East of Iran. The extracted earthquake catalog had a total of 6034 earthquakes (Mw?>?4) in the time span 1983–2017. The ETAS model is an accepted stochastic approach for seismic evaluation and declustering earthquake catalogs. However, this model has not yet been used to decluster the seismic catalog of Iran. Until now, traditional methods like the Gardner and Knopoff space–time window method and the Reasenberg link-based method have been used in most studies for declustering Iran earthquake catalog. Finally, the results of declustering by the ETAS model are compared with result of Gardner and Knopoff (Bull Seismol Soc Am 64(5):1363–1367, 1974), Uhrhammer (Earthq Notes 57(1):21, 1986), Gruenthal (pers. comm.) and Reasenberg (Geophys Res 90:5479–5495, 1985) declustering methods. The overall conclusion is difficult, but the results confirm the high ability of the ETAS model for declustering Iranian earthquake catalog. Use of the ETAS model is still in its early steps in Iranian seismological researches, and more parametric studies are needed. 相似文献
13.
Sławomir Jerzy Gibowicz 《Acta Geophysica》2006,54(2):142-157
The following criteria for selection of doublets at Polish coal mines were accepted: the difference in magnitude (based on
seismic moment) of two events not larger than 0.15, the distance between their hypocenters not greater than 150 m, and the
time interval between their occurrence not longer than 10 days. Similarly, the criteria for seismic events at copper mines
are: the difference in magnitude not exceeding 0.15, the distance not greater than 200 m, and the time interval not longer
than 20 days. Seismic events from the Wujek and Ziemowit coal mines that occurred between 1993 and 1995, and seismic events
from the Polkowice copper mine that occurred between 1994 and 1996 and from the Rudna copper mine that occurred between 1994
and 2004 were considered. Their source parameters and focal mechanisms were known in most cases from previous studies. Altogether
108 seismic pairs from coal mines and 118 pairs from copper mines were found, forming doublets, triplets and quadruplets,
within the magnitude range from 0.7 to 3.5. The distance and time intervals between two events forming pairs are not dependent
on magnitude of these events.
The focal mechanism of seismic events forming pairs is similar in over 60 percent of pairs at coal mines and in about one
third of pairs at copper mines. Spatial distributions of doublets in particular sections of coal and copper mines display
dominant linear trends, characteristic for a given area, which are often in conformity with the direction of nodal planes
determined by fault plane solution of one or both the events forming a doublet. In such cases, the rupture plane can be discriminated
among the nodal planes. 相似文献
14.
"Parametric-historic" Procedure for Probabilistic Seismic Hazard Analysis Part II: Assessment of Seismic Hazard at Specified Site 总被引:3,自引:0,他引:3
15.
— Seismic hazard analysis methods in mines are reviewed for the purpose of selecting the best technique. To achieve this goal, the most often-used hazard analysis procedure, which is based on the classical frequency-magnitude Gutenberg-Richter relation, as well as alternative procedures are investigated.¶Since the maximum regional seismic event magnitude m max is of paramount importance in seismic hazard analysis, this work provides a generic formula for the evaluation of this important parameter. The formula is capable of generating solutions in different forms, depending on the assumptions of the model of the magnitude distribution and/or the available information regarding past seismicity. It includes the cases (i) in which seismic event magnitudes are distributed according to the truncated frequency-magnitude Gutenberg-Richter relation, and (ii) in which no specific model of the magnitude distribution is assumed.¶Both synthetic, Monte-Carlo simulated seismic event catalogues, and actual data from the copper mine in Poland and gold mine in South Africa, are used to demonstrate the discussed hazard analysis techniques.¶Our studies show that the non-parametric technique, which is independent of the assumed model of the distribution of magnitude, provides an appropriate tool for seismic hazard assessment in mines where the magnitude distribution can be very complex. 相似文献
16.
Sarfraz Khan Muhammad Waseem Muhammad Asif Khan Waqas Ahmed 《Journal of Seismology》2018,22(4):841-861
A reliable and homogenized earthquake catalogue is essential for seismic hazard assessment in any area. This article describes the compilation and processing of an updated earthquake catalogue for Pakistan. The earthquake catalogue compiled in this study for the region (quadrangle bounded by the geographical limits 40–83° N and 20–40° E) includes 36,563 earthquake events, which are reported as 4.0–8.3 moment magnitude (MW) and span from 25 AD to 2016. Relationships are developed between the moment magnitude and body, and surface wave magnitude scales to unify the catalogue in terms of magnitude MW. The catalogue includes earthquakes from Pakistan and neighbouring countries to minimize the effects of geopolitical boundaries in seismic hazard assessment studies. Earthquakes reported by local and international agencies as well as individual catalogues are included. The proposed catalogue is further used to obtain magnitude of completeness after removal of dependent events by using four different algorithms. Finally, seismicity parameters of the seismic sources are reported, and recommendations are made for seismic hazard assessment studies in Pakistan. 相似文献
17.
18.
Recent developments of the Middle East catalog 总被引:8,自引:2,他引:6
Mehdi Zare Hamideh Amini Pouye Yazdi Karin Sesetyan Mine Betul Demircioglu Dogan Kalafat Mustafa Erdik Domenico Giardini M. Asif Khan Nino Tsereteli 《Journal of Seismology》2014,18(4):749-772
This article summarizes a recent study in the framework of the Global Earth model (GEM) and the Earthquake Model of the Middle East (EMME) project to establish the new catalog of seismicity for the Middle East, using all historical (pre-1900), early and modern instrumental events up to 2006. According to different seismicity, which depends on geophysical, geological, tectonic, and seismicity data, this region is subdivided to nine subregions, consisting of Alborz–Azerbaijan, Afghanistan–Pakistan, Saudi Arabia, Caucasus, Central Iran, Kopeh–Dagh, Makran, Zagros, and Turkey (Eastern Anatolia; after 30° E). After omitting the duplicate events, aftershocks, and foreshocks by using the Gruenthal method, and uniform all magnitude to Mw scale, 28,244 main events remain for the new catalog of Middle East from 1250 B.C. through 2006. The magnitude of completeness (Mc) was determined as 4.9 for five out of nine subregions, where the least values of Mc were found to be 4.2. The threshold of Mc is around 5.5, 5.0, 4.5, and 4.0, for the time after 1950, 1963, 1975, and 2000, respectively. The average of teleseismic depths in all regions is less than 15 km. Totally, majority of depth for Kopeh–Dagh and Central Iran, Zagros, and Alborz–Azerbaijan, approximately, is 15, 13, and 11 km and for Afghanistan–Pakistan, Caucasus, Makran, Turkey (after 30° E), and Saudi Arabia is about 9 km. 相似文献
19.
v--v Continuous seismic threshold monitoring is a technique that has been developed over the past several years to assess the upper magnitude limit of possible seismic events that might have occurred in a geographical target area. The method provides continuous time monitoring at a given confidence level, and can be applied in a site-specific, regional or global context.¶In this paper (Part 1) and a companion paper (Part 2) we address the problem of optimizing the site-specific approach in order to achieve the highest possible automatic monitoring capability of particularly interesting areas. The present paper addresses the application of the method to cases where a regional monitoring network is available. We have in particular analyzed events from the region around the Novaya Zemlya nuclear test site to develop a set of optimized processing parameters for the arrays SPITS, ARCES, FINES, and NORES. From analysis of the calibration events we have derived values for beam-forming steering delays, filter bands, short-term average (STA) lengths, phase travel times (P and S waves), and amplitude-magnitude relationships for each array. By using these parameters for threshold monitoring of the Novaya Zemlya testing area, we obtain a monitoring capability varying between mb 2.0 and 2.5 during normal noise conditions.¶The advantage of using a network, rather than a single station or array, for monitoring purposes becomes particularly evident during intervals with high global seismic activity (aftershock sequences), high seismic noise levels (wind, water waves, ice cracks) or station outages. For the time period November-December 1997, all time intervals with network magnitude thresholds exceeding mb 2.5 were visually analyzed, and we found that all of these threshold peaks could be explained by teleseismic, regional, or local signals from events outside the Novaya Zemlya testing area. We could therefore conclude within the confidence level provided by the method, that no seismic event of magnitude exceeding 2.5 occurred at the Novaya Zemlya test site during this two-month time interval.¶As an example of particular interest in a monitoring context, we apply optimized threshold processing of the SPITS array for a time interval around 16 August 1997 mb 3.5 event in the Kara Sea. We show that this processing enables us to detect a second, smaller event from the same site (mb 2.6), occurring about 4 hours later. This second event was not defined automatically by standard processing. 相似文献
20.
Source Characteristics of the 12 November 1996 Mw 7.7 Peru Subduction Zone Earthquake 总被引:1,自引:0,他引:1
—The 12 November 1996 M w 7.7 Peru subduction zone earthquake occurred off the coast of southern Peru, near the intersection of the South American trench and the highest topographical point of the subducting Nazca Ridge. We model the broadband teleseismic P-waveforms from stations in the Global Seismic Network to constrain the source characteristics of this subduction zone earthquake. We have analyzed the vertical component P-waves for this earthquake to constrain the depth, source complexity, seismic moment and rupture characteristics. The seismic moment determined from the nondiffracted P-waves is 3–5 × 1020 N·m, corresponding to a moment magnitude M w of 7.6–7.7. The source time function for the 1996 Peru event has three pulses of seismic moment release with a total duration of approximately 45–50 seconds. The largest moment release occurs at approximately 35–40 seconds and is located ~90km southeast of the rupture initiation. Approximately 70% of the seismic moment was released in the third pulse.¶We find that the 1996 event reruptured part of the rupture area of the previous event in 1942. The location of the 1996 earthquake corresponds to a region along the Peru coast with the highest uplift rates of marine terraces. This suggests that the uplift may be due to repeated earthquakes such as the 1996 and 1942 events. 相似文献