萨尔瓦多的教训

20 0多位来自政府机构、武装部队、救济机构、大学、非政府组织 ( NGOs)、市政当局和国际组织的有关人员于 7月 4～ 6日在萨尔瓦多开会 ,分析 1 2个不同地区对 2 0 0 1年年初地震的反应的强与弱。公共卫生部门、泛美卫生组织( PAHO)和国际减灾对策 ( ISDR)共同主办了这次会议 ,会议强调了以下几点结果 :1 )政府机构对于灾害做出了非常迅速的第一反应 ,地方组织和 NGOs在反应阶段采取行动也很一致 ,但是地震震级和余震频度超出了该国在协调一致方面做出反应的能力。2 )没有吸取以前灾害 (包括在萨尔瓦多造成 1 2 0 0多人死亡的 1 986年…     

2000年1月13日萨尔瓦多发生7.6级地震

据《新华社》、《美联社》、《路透社》等多家新闻媒体报道 ,2 0 0 1年 1月 13日当地时间中午 ,萨尔瓦多的拉巴斯省发生大地震 ,造成惨重人员伤亡和财产损失。1　地震参数1.1　发震时间主震发生在当地时间 2 0 0 1年 1月 13日中午 11时 34分 ;北京时间 1月 14日凌晨 0 1时35分 ;格林尼治时间 17时 34分。地震持续了约 30 s,此后断断续续发生了 5 2 3次余震 (截止 1月 15日 )。1.2　震中位置萨尔瓦多测定 ,这次大地震的震中位于首都圣萨尔瓦多东南 10 5 km的拉巴斯省 ;美国国家地震信息中心测定为 12 .8N,88.8W。1.3　震级美国地质调查局国…     

宁波台矿泉井水温异常与萨尔瓦多8.0级地震的关系

2001年1月9日起开始宁波台矿泉井井水温度出现异常，通过检查、分析后认为很可能与萨尔瓦多8.0级地震有关系。从日均值图上看，异常在震前6天开始出现，至震前1天达到最大，表现为打破正常的波动规律，呈负异常；从整点测值图看，主要是震前36小时出现负阶跃。分析认为出现的水温异常可能是一种地震前的长周期波通过上地幔或软流层传播而至，间接地影响地下流体发生微小的温度变化。     

地震应急指挥管理信息系统的探讨

地震应急指挥技术系统是防震减灾建设的核心内容，我国的研究和建设尚处于初级阶段。因此地震应急指挥管理信息系统的关键构成、设计和实现还有许多方面有待进一步研究和探讨。根据所从事的项目建设过程，对地震应急指挥技术系统几个方面的内容进行了阐述，并在此基础上开展了国务院抗震救灾指挥部技术系统建设一期工作。     

新疆巴楚M6.8地震房屋震害及经验总结

王亚勇1,葛学礼1,袁金西2(1.中国建筑科学研究院工程抗震研究所,北京100013;2.新疆维吾尔族自治区建筑设计研究院,新疆乌鲁木齐830000)1　震害基本情况调查2003年2月24日上午10时03分在我国新疆维吾尔族自治区喀什地区巴楚县发生震级为6.8的强烈地震,据我国地震台网测定,震中为东经77度15分,北纬39度29分。地震部门提供的等震线图表明,震中区沿北北西条带分布,长50多km;震中烈度为9度,影响范围280km2;8度区面积1200km2;7度区面积4300km2,见图1。　　地震波及八县一市,2万7千多户受灾,重灾户1万8千户,其中重灾区是巴楚县的3个乡。共有3万多间…     

2023年4—6月全球地震活动述评

以季度为周期通过多渠道收集地震灾害相关信息资料,对全球2020年以来发生的5.0级以上地震活动进行统计,重点对2023年4—6月发生的造成重大人员伤亡和经济财产损失的5.0级以上地震进行数据搜集、归纳整理和统计分析;对典型地震的地震灾害及其影响进行概括和阐述,总结2023年第二季度地震灾害活动主要特征,分析了全球地震活动和人员伤亡特点,强调日常抗震设防和培养应急避险意识的重要性。     

2023年1—3月全球地震活动述评

对全球2020年以来发生的5.0级以上地震活动进行统计,以季度为周期并通过多渠道收集地震灾害相关信息资料。重点对2023年1—3月发生的造成重大人员伤亡和经济财产损失的5.0级以上地震进行数据搜集、归纳整理和统计分析,对典型地震的地震灾害及其影响进行了概括和阐述,总结了2023年第一季度地震灾害活动情况主要特征,分析了全球地震活动和人员伤亡特点,强调日常抗震设防和培养应急避险意识的重要性。     

2023年7—9月全球地震活动述评

根据近三年以来全球5.0级以上地震数据,以季度为单位进行统计分析,汇总不同季度地震灾害造成的人员伤亡损失情况。重点对2023年7—9月发生的造成重大人员伤亡和财产损失的5.0级以上地震开展数据搜集、归纳整理和统计分析。通过对重大地震灾害及其伤亡情况进行分析,对比和总结近三年来同季度地震灾害活动情况,提出地震灾害应急避险及预防措施的重要性。     

地震人员伤亡预测与研究现状

前言１９９５年阪神淡路大震灾夺去了６４００多人的宝贵生命,是第二次世界大战后最严重的自然灾害。大震灾发生后,日本各地都对各自的区域防灾计划进行了修改。依据灾害对策基本法,日本全国每个自治体都有义务有针对性地制定各自地区的防灾计划。制定防灾计划的前提是...     

Strahlungsmessungen mit dem Bellani-Kugelpyranometer in El Salvador (Mittelamerika)

Zusammenfassung Der Jahresverlauf der Zirkumglobalstrahlung in El Salvador wird in seiner Abhängigkeit vom Jahresgang der Sonnenhöhe, den Bewölkungs- und Trübungsverhältnissen diskutiert. Der Zusammenhang zwischen dem Strahlungsgenuss einer Kugel und einer horizontalen Fläche wird im Hinblick auf die jahreszeitlich wechselnde Sonnenhöhe untersucht; es zeigt sich, dass die Globalstrahlung mit befriedigender Genauigkeit aus Messungen der Zirkumglobalstrahlung zu bestimmen ist. Die Beziehung zwischen Zirkumglobalstrahlung und Sonnenscheindauer bzw. Bewölkungsverhältnissen wechselt jahreszeitlich, entsprechend den mittleren Sonnenhöhen, und gestattet, lückenhafte Messreihen der Zirkumglobalstrahlung nach Registrierungen der Sonnenscheindauer zu reduzieren.

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Summary The annual variation of circumglobal radiation in El Salvador, depending on the seasonal change of solar height, cloudiness and turbidity, is discussed. The relation between the radiation received on a sphere and a horizontal surface on the other hand, is examined with respect to seasonal change of solar height; global radiation is to be determined from measurements of circumglobal radiation with satisfactory accuracy. The relation between circumglobal radiation and sunshine duration or cloud conditions, changes throughout the year, according to mean solar height; uncomplete series of circumglobal radiation can be reduced after records of the duration of sunshine.

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Resumen El transcurso anual de la radiación circumglobal en El Salvador es discutido con referencia a la variación anual de la altura del Sol, la nubosidada y la turbiedad. La relación entre la cantidad de radiación recibida por una esfera y una superficie horizontal, por otra parte, es investigada con respecto al cambio estacional de la altura del sol; resulta que la radiación global es a determiner con satisfactoria exactitud. a base de mediciones de la radiación circunglobal. La relación entre radiación circunglobal y duración del brillo solar o nubosidad, respectivamente, varía segun la estación del año, correspondientemente a la altura media del sol; series cortos o incompletos de la radiación circunglobal pueden ser reducidas segun registros de la duración de la luz solar.

     

Relation of lava compositions to volcano size and structure in El Salvador

Most of the lavas at the nine volcanic centers along the volcanic front of El Salvador are basalts, basaltic andesites and andesites. The compositional variation within and among these centers can be explained by fractionation processes within the crust. Cognate gabbroic inclusions found in the lavas have appropriate mineralogy (plagioclase, olivine, magnetite and augite) to be cumulates formed by fractional crystallization. Two main variation trends occur, depending on the proportion of plagioclase removal. The more common, or normal, trend has a high (> 55%) proportion of plagioclase being removed. A less common, Al-rich, trend has a low (40%) proportion of plagioclase being removed. The Al-rich trend is found only at volcanoes that lack large negative Bouguer gravity anomalies. These volcanoes are unlikely to have large shallow magma chambers and fractionation probably occurs deeper in the crust where plagioclase removal is inhibited.The incompatible element (Na₂O, K₂O, Rb, Ba) contents of lavas vary systematically with the volume of the volcanic centers. At the same level of SiO₂, large volcanic centers have higher incompatible element contents than small volcanic centers. This suggests that open system fractionation in a periodically refilled chamber is the controlling factor. The large difference in Ba contents of lavas between eastern (low) and western (high) El Salvador suggests a difference in the mantle source region.     

Vanadium sublimates from the fumaroles of Izalco volcano, El Salvador

Prior to the recent discovery of high-temperature vanadium sublimates at the fumaroles of Izalco volcano, El Salvador, the only vanadium minerals known were those formed at low-temperature surface conditions. Six new vanadium compounds have already been discovered at Izalco volcano, and five of these have been elevated to mineral status. Two of the minerals are among the most vanadium-rich compounds known in nature.Field studies and studies of the crystal chemistry of the sublimate phases have allowed delineation of the conditions of exsolution of vanadium-bearing gases from the magma and conditions of sublimation of the vanadium compounds. A vanadium halogen or oxyhalogen gas phase was exsolved from a basaltic magma when the magma was 550 m below the summit crater. As the gas rose to the fumaroles and mixed with the atmosphere, the oxygen fugacity rose from that of the magma to at least 10^−3,5 bar. At the fumaroles, the vanadium compounds sublimated at various temperatures, but a minimum temperature of 760° can be determined for one of the phases based on geothermometry determined from phase relations in the system CuO-V₂O₅. The studies have demonstrated that a vanadium-bearing gas can segregate from a magma with normal basaltic concentrations of vanadium.     

The earthquake sequence of May 1951 at Jucuapa, El Salvador

Three earthquakes that happened over two days in May 1951 caused extensive damage to villages in a small area of eastern El Salvador (Central America). Contemporary hypocentral solutions indicated focal depths, confirmed by re-calculations using available seismic data, of the order of 90 km, suggesting events associated with the subducted Cocos plate. Macroseismic observations strongly indicate that the earthquakes were of very shallow focus and this is supported by wave-form modeling and the appearance of seismograms recorded in Guatemala. A re-evaluation of the location and source characteristics for these events is presented, together with a fault plane solution and additional macroseismic evidence. The implications for seismic hazard and risk assessment in Central America, where shallow earthquakes of moderate magnitude, frequently occurring in clusters, pose the greatest threat to settlements which, like the area affected by these events, are concentrated along the axis of Quaternary volcanoes.     

2001年的萨尔瓦多:热带火山环境中的地震灾害及防灾

应萨尔瓦多驻墨西哥大使馆的邀请 ,在2 0 0 1年 1月 1 3日灾害性地震 ( MW=7.6)之后2个星期 ,我们访问了萨尔瓦多。我们一行人中曾有一位在这个国家研究过早期地震灾害( L omnitz and Schultz,1 966)。本文就是我们现场考察的结果。1　地震概况主震 ( MW=7.6)发生于当地时间 2 0 0 1年1月 1 3日星期六上午 1 1时 3 3分 ,震中位于萨尔瓦多南海岸 ( 1 2 .80°N,88.78°W) ,震源深度约 40 km。第 2次较大地震 ( MW=6.6)发生于 2 0 0 1年 2月 1 3日 ,震中位于内陆 1 3 .64°N88 .94°W处 ,震源深度 1 3 km。地震共导致1 1 0 0多人死亡 ,且…     

The 2005 eruption of Ilamatepec (Santa Ana) volcano,El Salvador

We report the stratigraphic sequence of the 2005 eruption of Ilamatepec volcano together with sedimentological and chemical analyses of its products.Structural and textural characteristics of the deposits indicate that the eruption was driven by a small-volume rhyolitic intrusion at shallow levels, which resulted first in the collapse of the existing hydrothermally altered fan of previous deposits inside the crater lake, driving phreatic explosions with launching of blocks on ballistic trajectories; later the magma interacted with lake waters producing several hydromagmatic pyroclastic density currents (PDCs). These flows were energetic enough to knock down pine trees up to distances of 1.8 km from the crater in the E-NE sector of the volcano. Finally, ejection of ballistic blocks that landed on previously emplaced, wet pyroclastic density current deposits, caused the generation of a lahar that flowed down the steep eastern flank toward the El Jabillal gully. Subsequent lahars occurred as a result of intense rain caused by hurricane Stan.Radiocarbon ages on paleosols and charcoal fragments, separating previous volcanogenic sequences, indicate that similar eruptions have occurred more frequently in the past centuries, than previously thought.The new data confirms that Ilamatepec volcano is one of the most active volcanoes in El Salvador. Nevertheless, more detailed studies of the eruptive sequence of Ilamatepec volcano are mandatory to establish future eruptive patterns.     

Marine environmental impact due to mining activities of El Salvador copper mine,Chile

Marine environmental impact as a result of copper mine tailing dumping in the sea is studied at Chañaral (North of Chile). These dumpings, from the copper mine El Salvador, have hindered harbour activities, caused geomorphological coastal modifications and affected seriously marine coastal ecosystems and recreational activities. At the old dumping site, Chañaral Bay (1938–1974), nearly 150 million tons of fine sediments were accumulated. Tailing discharges at the new dumping site, Caleta Palito, about 8 km north of Chañaral Bay are accumulating approximately at the rate of 25 000 tons of fine sediments per day, plus unknown quantities of chemicals (Cu, As, CN^?). From January 1975 to July 1976, this site has received over 13 million tons of sediments which has caused deterioration of the marine coastal environment, reduction in light penetration and high mortalities among marine invertebrates, fishes and algae.     

Three thousand years of flank and central vent eruptions of the San Salvador volcanic complex (El Salvador) and their effects on El Cambio archeological site: a review based on tephrostratigraphy

The volcanic events of the last 3,000?years at San Salvador volcanic complex are reviewed using detailed stratigraphic records exposed in new excavations between 2005 and 2007, at El Cambio archeological site (Zapotitán Valley, El Salvador), and in other outcrops on the northern and northwestern sectors of the complex. The sequences that overlie Tierra Blanca Joven (cal. 429?±?107?ad), from the Ilopango caldera, comprise the Loma Caldera (cal. 590?±?90?ad) and El Playón (1658?C1671) deposits and the San Andrés Tuff (cal. 1031?±?29?ad), related to El Boquerón Volcano. The surge deposits within the El Playón, San Andrés Tuff and overlying Talpetate II sequences indicate the significance of phreatomagmatic phases in both central vent and flank eruptions during the last 1,600?years. Newly identified volcanic deposits underlying Tierra Blanca Joven at El Cambio extend the stratigraphic record of the area to 3,000?years?bp. Paleosols interstratified with those deposits contain cultural artifacts which could be associated with the Middle Preclassic period (900?C400?bc). If correct, human occupation of the site during the Preclassic period was more intense than previously known and volcanic eruptions must have affected prehistoric settlements. The archeological findings provide information on how prehistoric populations dealt with volcanic hazards, thousands of years ago in the eastern Zapotitán Valley, where several housing projects are currently being developed. The new stratigraphic and volcanological data can be used as a basis for local and regional hazard assessment related to future secondary vent activity in the San Salvador Volcanic Complex.     

Metal speciation and environmental impact on sandy beaches due to El Salvador copper mine, Chile

Several coastal rocky shores in northern Chile have been affected by the discharges of copper mine tailings. The present study aims to analyze the chemical speciation of heavy metals in relation to the diversity of sessile species in the rocky intertidal benthic community on the northern Chilean coast, which is influenced by the presence of copper mine tailings. In particular, the chemical forms of Cd, Cu, Fe, Mn, Ni, Pb and Zn in beach sediment samples collected in the area influenced by El Salvador mine tailings were studied using a sequential chemical extraction method. In general, all the elements present a maximum concentration in the area near the actual discharge point (Caleta Palito). With regard to Cu and Mn, the concentrations range between 7.2-985 and 746-22,739 microg/g respectively, being lower than background levels only in the control site of Caleta Zenteno. Moreover, the correlation coefficients highlight that Fe, Mn and Ni correlate significantly and positively in the studied area, showing a possible common, natural origin, whilst Cu shows a negative correlation with Fe, Mn and Ni. It could be possible that Cu has an anthropogenic origin, coming from mining activity in the area. Cd, Fe, Mn, Ni, Pb and Zn are mostly associated with the residual phase, whilst Cu presents a different speciation pattern, as resulted from selective extractions. In fact, Cu is highly associated with organic and exchangeable phases in contaminated localities, whilst it is mainly bound to the residual phase in control sites. Moreover, our results, compared to local biological diversity, showed that those sites characterized by the highest metal concentrations in bioavailable phase had the lowest biodiversity.