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1.
Taking the northeastern Fujian area as an example, we provide some new technological ideas and contents for the historical earthquake investigation of significant engineering construction sites. ① Make sure the integrity of earthquake materials with reference to the regional histories of culture and disasters; ② Evaluate the influence of historical earthquakes on the basis of actual records, review and identify the epicenter location and magnitude of destructive earthquakes. The research by the new technological ideas will endue the investigation of historical earthquakes with new meanings in the cultural phylogeny and credible time domain, so as to make the results of historical earthquake research more scientific. The aim of the paper is to improve the level of historical earthquake investigation for a better service to the engineering construction. 相似文献
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Introduction From the records of Wudalianchi volcanic group eruption in 1720~1721 obtained from the Man ethnic group files of Heilongjiang General Yamen in Qing Dynasty (WU, 1998; CHEN, WU, 2003), we have discovered the eruption time, state, material and scale of Laoheishan and Hu-oshaoshan volcanoes, as well as numerous seismic records. These historical materials are discov-ered for the first time although the study on Wudalianchi volcanic group has a long history. These earthquakes co… 相似文献
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In this study we use the term record threshold of a historical earthquake for the seismic intensity (EMS92) in an area where a given percentage P of the serial sources of places have recorded the event as been noticed there. The record threshold is understood as a limiting measure, below which warranted statements about the intensity cannot be given. P defines the acceptable uncertainty and can be chosen according to the demands of the special task, for instance, 10%. It is shown that the record threshold of historical earthquakes is not the same as the human perceptibility threshold of earthquakes of the 20th Century. The historical sources have to be selected using criteria such as completeness and homogenity of data. This demand is approximately met by inquiries for sources covering an area greater than the expected felt area of the historical earthquake.The Friuli event of 25 January 1348 is presented as an example. It is compared with the well known Friuli event of 6 May 1976 in order to calibrate its intensity. The record threshold of the 1348 event was probably IV or less than IV EMS92 for P = 10%. The method, properly modified, can be applied to different cultural epochs and areas. This result throws a light on the possible error in determining the felt area of historical events. 相似文献
4.
Amos Salamon 《Journal of Seismology》2010,14(2):339-367
There are historical accounts of about a hundred damaging earthquakes that occurred during the last two millennia in the Levant,
in and around the Dead Sea fault system, and about half of which were associated with additional felt shocks. Several modes
of earthquake sequences can be distinguished in them: (a) In 46 accounts, only one single event is noted. These are not known
from tectonic settings similar to that of the Levant, and may just be a result of incomplete reporting. (b) In four cases,
quakes preceded the mainshock by minutes, hours, and up to several weeks—possibly foreshocks. (c) Thirty-five mainshock–aftershock
sequences were noted, lasting hours, days, weeks, months, and even more than a year; four of these also have foreshocks. No
typical delay time was recognized for the largest or most significant aftershocks: they appeared up to several months later.
(d) Six of the reported mainshock–aftershock sequences appeared in a “storm.” Another 13 sequences are insufficient to specify
further. 相似文献
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The historical earthquake data is one of the important foundations for seismic monitoring, earthquake fore-cast and seismic safety evaluation. However, the recognition of earthquake is limited by the scientific and techno-logical level. Therefore, the earthquake can only be described using perfect earthquake catalogue after the seismo-graph is invented. Before this time, the earthquake parameters were determined according to the earthquake disas-ter on the surface and the written records in hi… 相似文献
6.
Introduction In the region of Jiangsu Province and South Huanghai Sea, only 14 M4.7 earthquakes (ex-cluding aftershocks and other main shocks in the swarm) occurred from 1970 when microseismic observation net was built. It is very difficult to objectively distinguish the law of earthquake series distribution in a region based on these data. However, from the antiquity in China, Jiangsu is an area with flourish economy and a galaxy of talent and culture. In Jiangsu, historical data are so c… 相似文献
7.
The 2015/16 El Nio developed from weak warm conditions in late 2014 and NINO3.4 reached 3℃ in November 2015. We describe the characteristics of the evolution of the 2015/16 El Nio using various data sets including SST, surface winds,outgoing longwave radiation and subsurface temperature from an ensemble operational ocean reanalyses, and place this event in the context of historical ENSO events since 1979. One salient feature about the 2015/16 El Nio was a large number of westerly wind bursts and downwelling oceanic Kelvin waves(DWKVs). Four DWKVs were observed in April-November 2015 that initiated and enhanced the eastern-central Pacific warming. Eastward zonal current anomalies associated with DWKVs advected the warm pool water eastward in spring/summer. An upwelling Kelvin wave(UWKV) emerged in early November 2015 leading to a rapid decline of the event. Another outstanding feature was that NINO4 reached a historical high(1.7℃), which was 1℃(0.8℃) higher than that of the 1982/83(1997/98) El Nio . Although NINO3 was comparable to that of the 1982/83 and 1997/98 El Nio , NINO1+2 was much weaker. Consistently, enhanced convection was displaced 20 degree westward, and the maximum D20 anomaly was about 1/3.1/2 of that in 1997 and 1982 near the west coast of South America. 相似文献
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In this paper we present a site effects analysis carried out in Málaga city’s historical centre (Southern Spain). Two different methodologies have been used: an experimental technique using ambient noise measurements and a 1D numerical method. Soil fundamental frequencies have been obtained from the first technique, and soil transfer functions have been calculated from the numerical methodology. In order to use these results in vulnerability studies, intensity increments for each type of soil have also been estimated. From this information, a seismic microzonation has been proposed for the city centre, classified in six types of soils. Soil fundamental frequencies vary between above 5.0Hz at the hills of the city (where rock arises on the surface), and 1.0Hz near Guadalmedina river. The results show regions with high intensity increments (ΔI = +1.5) corresponding to areas which suffered heavy damage in the 1680 earthquake (Imax = VIII–IX). Moreover, most of the monuments and historical buildings in the city are located in these high risk areas. Results underline the importance of this kind of studies for seismic risk mitigation, historical preservation and emergency planning in the main cities’ historical centres. 相似文献
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Small centres damaged by 2009 L’Aquila earthquake: on site analyses of historical masonry aggregates
Caterina F. Carocci 《Bulletin of Earthquake Engineering》2012,10(1):45-71
This paper is focused on the illustration of on site works developed on some historical centres struck by L’Aquila earthquake
of April 6, 2009 starting from the first emergency phase. The large number of minor historical centres damaged and the highly
differentiated level of damage occurred implied the need of different procedures to study them. The common goal of all these
studies is to illustrate the variability of the seismic response of historical masonry buildings trying to identify both the
causes that have increased the damage (vulnerabilities) and the factors that have limited or prevented it (strengths). The
preliminary results allow to formulate a first evaluation in view of drawing up reconstruction plans. 相似文献
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On 6 April 2009 a Mw=6.1 earthquake produced severe destruction and damage over the historic center of L’Aquila City (central Italy), in which the accelerometer stations AQK and AQU recorded a large amount of near-fault ground motion data. This paper analyzes the recorded ground motions and compares the observed peak accelerations and the horizontal to vertical response spectral ratios with those revealed from numerical simulations. The finite element method is considered herein to perform dynamic modeling on the soil profile underlying the seismic station AQU. The subsurface model, which is based on the reviewed surveys that were carried out in previous studies, consists of 200–400 m of Quaternary sediments overlying a Meso-Cenozoic carbonate bedrock. The Martin-Finn-Seed's pore-water pressure model is used in the simulations. The horizontal to vertical response spectral ratio that is observed during the weak seismic events shows three predominant frequencies at about 14 Hz, 3 Hz and 0.6 Hz, which may be related to the computed seismic motion amplification occurring at the shallow colluvium, at the top and base of the fluvial-lacustrine sequence, respectively. During the 2009 L’Aquila main shock the predominant frequency of 14 Hz shifts to lower values probably due to a peculiar wave-field incidence angle. The predominant frequency of 3 Hz shifts to lower values when the earthquake magnitude increases, which may be associated to the progressive softening of soil due to the excess pore-water pressure generation that reaches a maximum value of about 350 kPa in the top of fluvial-lacustrine sequence. The computed vertical peak acceleration underestimates the experimental value and the horizontal to vertical peak acceleration ratio that is observed at station AQU decreases when the earthquake magnitude increases, which reveals amplification of the vertical component of ground motion probably due to near-source effects. 相似文献
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The most recent high magnitude seismic events, e.g. the Mw 8.2 Iquique earthquake (April 1st, 2014) and the Mw 8.8 Maule earthquake (February 27th, 2010) are reminders of the pronounced vulnerability of the Chilean coast to the impact of natural hazards like earthquakes and tsunamis. Therefore it is crucial to understand the complex tsunami history of Chile which can be deciphered by studying the geological record of former tsunamis in the form of tsunami deposits.At the coastal locality of Tirúa (Central Chile) six distinct, successive tsunamigenic sand layers are intercalated in fine grained floodplain sediments. We present the optically stimulated luminescence (OSL) analysis of quartz from samples of this sedimentological river marsh profile of 1.5 m depth.After the assessment of the applicability of OSL to these samples, it could be noted that despite of an expected low OSL sensitivity of the quartz from the South American Cordillera, most of the sampled quartz yielded a detectable natural signal. After performance tests according to the SAR-protocol, the measurements of the different tsunami sand layers were conducted with small (2.5 mm) aliquots of quartz with the preheat temperature 180 °C. The calculation of De was provided by applying both the central age and minimum age models. All samples are heterogeneous in their De distributions due to incomplete or absent significant bleaching during transport by tsunami. The resulting ages of the tsunami sediments yield an offset of nearly 200 years for CAM ages and less than 50 years for MAM ages, consequently favouring MAM ages for true burial age determination. In some tsunami sand layers and their surrounding river marsh sediments age inversions occur. They were caused by the initial deposition of well bleached sediments derived from beach and dunes followed by older sediments redeposited from beach and intertidal environments during tsunami flow. Despite the offset and age inversion six different tsunami events were dated in the Tirúa profile. Three of these events extend the historical record to pre-Columbian time with the oldest tsunami dated to over 1500 years before present. 相似文献
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ABSTRACTJoint frequency analysis and quantile estimation of extreme rainfall and runoff (ERR) are crucial for hydrological engineering designs. The joint quantile estimation of the historical ERR events is subject to uncertainty due to the errors that exist with flow height measurements. This study is motivated by the interest in introducing the advantages of using Hydrologic Simulation Program-Fortran (HSPF) simulations to reduce the uncertainties of the joint ERR quantile estimations in Taleghan watershed. Bivariate ERR quantile estimation was first applied on PAMS-QSIM pairs and the results were compared against the historical rainfall–runoff data (PAMS-Qobs). Student’s t and Frank copulas with respectively Gaussian-P3 and Gaussian-LN3 marginal distributions well suited to fit the PAMS-Qobs and PAMS-QSIM pairs. Results revealed that confidence regions (CRs) around the p levels become wider for PAMS-Qobs compared to PAMS-QSIM, indicating the lower sampling uncertainties of HSPF simulations compared to the historical observations for bivariate ERR frequency analysis. 相似文献
16.
The seismicity of Algeria since the nineteenth century is relatively well documented. However, compared with the numerous damaging earthquakes that are documented since 1850, fewer than a dozen reports of earthquakes are listed for the pre-1850 ad period, suggesting that the historical record is missing a substantial number of earthquakes. This paper examines the use of literary and epigraphic sources relevant to the investigation of seismicity in Algeria during Roman times. We provide examples where the meager written literary record may be supplemented with appropriate archaeological and epigraphic data describing damage to ancient Roman sites. The examples show that collaboration between earth scientists and archeologists is of utility in improving the seismic record and highlights the need for further study of data sources and repositories located both inside and outside of Algeria. 相似文献
17.
Vulnerability and risk analysis of monuments in Málaga city’s historical centre (Southern Spain) 总被引：1，自引：1，他引：0
A vulnerability analysis of some historical and monumental buildings in the city of Málaga is presented in this paper. More than twenty of these monuments were severely damaged or completely destroyed due to the large earthquake (I max = VIII–IX) occurred in the Málaga region in October 1680. The vulnerability index methodology has been used in this paper. This technique is based on statistical data from seismic damage caused to Italian monuments for the past 30?years. For each building, vulnerability curves have been obtained and damage grades have been estimated. A comparison has been carried out between the expected damage grades and the damage observed from past earthquakes, in order to check the feasibility of applying this methodology to Spanish monuments. This comparison has been possible due to the fact that detailed seismic damage information exists for monuments in the city of Málaga that still exist today, which is a very uncommon case in Spain. Results show a good consistency between expected and observed damage, especially for the churches type. Two seismic scenarios have been proposed for the city centre, one deterministic and one probabilistic, where 54 historical and modern buildings have been analyzed. Both scenarios show worrying results, especially for the types of churches, chapels and towers, where expected high probabilities of suffering very heavy damage or even collapse have been obtained. It is highly recommended to take the necessary measures, in the hope of trying to avoid the possible damage that can be expected from future earthquakes. 相似文献
18.
Abstract The reassessment of flood risk at York, UK, is pertinent in light of major flooding in November 2000, and heightened concerns of a perceived increase in flooding nationally. Systematic flood level readings from 1877 and a wealth of documentary records dating back as far as 1263 AD give the City of York a long and rich history of flood records. This extended flood record provides an opportunity to reassess estimates of flood frequency over a time scale not normally possible within flood frequency analysis. This paper re-evaluates flood frequency at York, considering the strengths and weaknesses in estimates resulting from four contrasting methods of analysis and their corresponding data: (a) single-site analysis of gauged annual maxima; (b) pooled analysis of multi-site gauged annual maxima; (c) combined analysis of systematic annual maxima augmented with historical peaks, and (d) analysis of only the very largest peaks using a Generalized Pareto Distribution. Use of the historical information was found to yield risk estimates which were lower and considered to be more credible than those achieved using gauged records alone. Citation Macdonald, N. & Black, A. R. (2010) Reassessment of flood frequency using historical information for the River Ouse at York, UK (1200–2000). Hydrol. Sci. J. 55(7), 1152–1162. 相似文献
19.
N. G. Ptitsyna I. M. Demina M. I. Tyasto B. A. Khrapov 《Geomagnetism and Aeronomy》2013,53(5):642-649
Geomagnetic field parameters have been measured in different sites of the northwest of Russia for hundreds of years. This work presents the results of numerous measurements in St. Petersburg, as well as in the Gulf of Finland within the zone from 25° to 30°30′ E and from 59° to 61° N. The first measurements were made in the period1630–1650. For this work, archival data, provided by the Archives of the St. Petersburg Magnetic Observatory (SPbF IZMIRAN), and data from different historical records have been used. Data on the Earth’s magnetic field variations in St. Petersburg have been recorded since 1726; they were analyzed and corrected to get a uniform and complete data set. The reconstructed long-term data set of magnetic variation measurements in St. Petersburg was compared with the GUFM1 historical model. This model allows us to calculate the values of all parameters of the main magnetic field in any place on the Earth since 1590. The comparative analysis carried out by us has revealed a discrepancy between the model and measured values. This discrepancy can be caused by local secular variations in the magnetic field in the St. Petersburg region. The correction of the area-averaged secular variation makes this discrepancy insignificant. 相似文献