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1.
本文叙述了新发现的有关五大连池老黑山,火烧山两座近代火山喷发过程的清化清文料档案的主要内容。在此基础上讨论了火山发过程及有关问题,同时评议了这些史料的学术价值． 相似文献
2.
We have documented 80 tephra beds dating from ca. 9.5 to >50 ka, contained within continuously deposited palaeolake sediments from Onepoto Basin, a volcanic explosion crater in Auckland, New Zealand. The known sources for distal (>190 km from vent) tephra include the rhyolitic Taupo Volcanic Centre (4) and Okataina Volcanic Centre (14), and the andesitic Taranaki volcano (40) and Tongariro Volcanic Centre (3). The record provides evidence for four new events between ca. 50 and 28 ka (Mangaone Subgroup) suggesting Okataina was more active than previously known. The tephra record also greatly extends the known northern dispersal of other Mangaone Subgroup tephra. Ten rhyolitic tephra pre-date the Rotoehu eruption (>ca. 50 ka), and some are chemically dissimilar to post-50 ka rhyolites. Some of these older tephra were produced by large-magnitude events; however, their source remains uncertain. Eight tephra from the local basaltic Auckland Volcanic Field (AVF) are also identified. Interpolation of sedimentation rates allow us to estimate the timing of 12 major explosive eruptions from Taranaki volcano in the 27.5-9.5-ka period. In addition, 28 older events are recognised. The tephra are trachytic to rhyolitic in composition. All have high K2O contents (>3 wt%), and there are no temporal trends. This contrasts with the proximal lava record that shows a trend of increasing K2O with time. By combining the Onepoto tephra record with that of the previously documented Pukaki crater, 15 AVF basaltic fall events are constrained at: 34.6, 30.9, 29.6, 29.6, 25.7, 25.2, 24.2, 23.8, 19.4, 19.4, 15.8 and 14.5 ka, and three pre-50 ka events. This provides some of the best age constraints for the AVF, and the only reliable data for hazard recurrence calculations. The minimum event frequency of both distal and local fall events can be estimated, and demonstrates the Auckland City region is frequently impacted by ash fall from many volcanoes. 相似文献
3.
Tsepelev I. A. Ismail-Zadeh A. T. Melnik O. E. 《Izvestiya Physics of the Solid Earth》2021,57(2):257-265
Izvestiya, Physics of the Solid Earth - Abstract—Volcanic eruptions belong to the extreme events that change the Earth’s landscape and affect global climate and environment. Although... 相似文献
4.
G. R. T. Clacy 《Bulletin of Volcanology》1972,36(1):20-28
Volcanic prediction using slow motion tape recorders suitably situated near a volcano, produce good correlations when frequency analysis techniques are used with total energy from semi-continuous tremors, apparent explosions determined to disregard tectonic events. 相似文献
5.
天津市地震局地震事件共享系统的设计与实现 总被引：3，自引：3，他引：0
分析了天津市测震台网历史数据的使用现状,并利用PHP语言和百度地图API程序的二次开发,建立了天津市地震局地震事件共享系统。利用该系统实现了天津市地震局历史地震事件的共享,用户可通过共享系统查询地震目录和下载地震事件,通过My Sql数据库语言设计系统各功能模块相关数据库表单,保存地震目录信息、用户反馈信息相关图片。该系统通过SESSION变量实现用户权限管理,避免了事件文件误传的可能性。通过该系统平台的投入使用,提升了系统原有地震事件保存方式,方便了用户查询使用事件文件的效率,使数据共享工作在天津市地震局得到了提升。 相似文献
6.
Two explosive eruptions occurred on 2 January 1996 at Karymsky Volcanic Center (KVC) in Kamchatka, Russia: the first, dacitic, from the central vent of Karymsky volcano, and the second, several hours later, from Karymskoye lake in the caldera of Akademia Nauk volcano. The main significance of the 1996 volcanic events in KVC was the phreatomagmatic eruption in Karymskoye lake, which was the first eruption in this lake in historical time, and was a basaltic eruption at the acidic volcanic center. The volcanic events were associated with the 1 January Ms 6.7 (Mw 7.1) earthquake that occurred at a distance of about 9–17 km southeast from the volcanoes just before the eruptions. We study the long-term (1972–1995) and short-term (1–2 January 1996) characteristics of crustal deformations and seismicity before the double eruptive event in KVC. The 1972–1995 crustal deformation was homogeneous and characterized by a gradual extension with a steady velocity. The seismic activity in 1972–1995 developed at the depth interval from 0 to 20 km below the Akademia Nauk volcano and spread to the southeast along a regional fault. The seismic activity in January 1996 began with a short sequence of very shallow microearthquakes (M ~0) beneath Karymsky volcano. Then seismic events sharply increased in magnitude (up to mb 4.9) and moved along the regional fault to the southeast, culminating in the Ms 6.7 earthquake. Its aftershocks were located to the southeast and northwest from the main shock, filling the space between the two active volcanoes and the ancient basaltic volcano of Zhupanovsky Vostryaki. The eruption in Karymskoye lake began during the aftershock sequence. We consider that the Ms 6.7 earthquake opened the passageway for basic magma located below Zhupanovsky Vostryaki volcano that fed the eruption in Karymskoye lake. 相似文献
7.
Analysis of the patterns of eruption occurrences may improve our understanding of volcanic processes. In this paper, the available historical data of an individual volcano, Colima in México, are used to classify its eruptions by size using the Volcanic Explosivity Index (VEI). The data shows that, if eruptions are only taken into account above a certain VEI level, the stochastic process associated with the explosive volcanic events can be represented by a non-stationary Poisson point process, which can be reduced to a homogeneous Poisson process through a transformation of the time axis. When eruptions are separated by VEI values, the occurrence patterns of each magnitude category can also be represented by a Poisson distribution. Analysis of the rate of occurrence of all eruptions with VEI greater than 1 permits the recognition of three distinct regimes or rates of volcanic activity during the last 430 years. A double stochastic Poisson model is suggested to describe this non-stationary eruptive pattern of Colima volcano and a Bayesian approach permits an estimation the present hazard. 相似文献
8.
万历二十五年八月二十六日(公元1597年10月6日)在中国东部七个省记载了一次特殊的地震事件,事件的中心大致在渤海湾。 其特殊性表现在:1.影响范围大而各地的震动程度基本相同,2.没有记载房屋破坏和强烈的振动感觉,而伴随有地表水和地下水的活动,3.某些地方有地面裂缝,4.当天和第三天分别在中国长白山和朝鲜咸镜道发生火山喷发。 由历史记载表明,该事件引起的地震动具有丰富的长周期成份,可能为慢地震事件。 这次事件发生在1556年关中大地震后,这次事件以后的100多年华北紧接着发生4次M8级的大地震。是否它是十七世纪华北大地震活动高潮来临前的预兆,值得重视。 相似文献
9.
Sally H. Potter Bradley J Scott Gill E Jolly Vince E Neall David M Johnston 《Bulletin of Volcanology》2015,77(9):77
Accurately observing and interpreting volcanic unrest phenomena contributes towards better forecasting of volcanic eruptions, thus potentially saving lives. Volcanic unrest is recorded by volcano observatories and may include seismic, geodetic, degassing and/or geothermal phenomena. The multivariate datasets are often complex and can contain a large amount of data in a variety of formats. Low levels of unrest are frequently recorded, causing the distinction between background activity and unrest to be blurred, despite the widespread usage of these terms in unrest literature (including probabilistic eruption-forecasting models) and in Volcanic Alert Level (VAL) systems. Frequencies and intensities of unrest episodes are not easily comparable over time or between volcanoes. Complex unrest information is difficult to communicate simply to civil defence personnel and other non-scientists. The Volcanic Unrest Index (VUI) is presented here to address these issues. The purpose of the VUI is to provide a semi-quantitative rating of unrest intensity relative to each volcano’s past level of unrest and to that of analogous volcanoes. The VUI is calculated using a worksheet of observed phenomena. Ranges for each phenomenon within the worksheet can be customised for individual volcanoes, as demonstrated in the companion paper for Taupo Volcanic Centre, New Zealand (Potter et al. 2015). The VUI can be determined retrospectively for historical episodes of unrest based on qualitative observations, as well as for recent episodes with state-of-the-art monitoring. This enables a long time series of unrest occurrence and intensity to be constructed and easily communicated to end users. The VUI can also assist with VAL decision-making. We present and discuss two approaches to the concept of unrest. 相似文献
10.
M. Pazirandeh 《Bulletin of Volcanology》1973,37(4):573-585
Volcanic rocks in Iran have been subdivided into three geographical groups: a belt extending from Maku district to Bazman, the Alborz Mountains, and East Iran. The average composition of the volcanic rocks is andesitic, although other rock types such as dacite, basalt and alkaline rocks have also been reported. In Iran, as elsewhere, the volcanics can be related to tectonic events (orogenic movements or laulting) and to the modern plate tectonics. 相似文献
11.
Abstract The Dras 1 Volcanic Formation of the Ladakh Himalaya, India, represents the eastern, upper crustal equivalent of the lower crustal gabbros and mantle peridotites of the Kohistan Arc exposed in Pakistan. Together these form a Cretaceous intraoceanic arc now located within the Indus Suture zone between India and Eurasia. During the Late Cretaceous, the Dras–Kohistan Arc, which was located above a north-dipping subduction zone, collided with the south-facing active margin of Eurasia, resulting in a switch from oceanic to continental arc volcanism. In the present study we analyzed samples from the pre-collisional Dras 1 Volcanic Formation and the postcollisional Kardung Volcanic Formation for a suite of trace elements and Nd isotopes. The Kardung Volcanic Formation shows more pronounced light rare earth element enrichment, higher Th/La and lower ɛNd values compared with the Dras 1 Volcanic Formation. These differences are consistent with an increase in the reworking of the continental crust by sediment subduction through the arc after collision. As little as 20% of the Nd in the Dras 1 Volcanic Formation might be provided by sources such as the Karakoram, while approximately 45% of the Nd in the Kardung Volcanic Formation is from this source. However, even before collision, the Dras–Kohistan Arc shows geochemical evidence for more continental sediment contamination than is seen in modern western Pacific arcs, implying its relative proximity to the Eurasian landmass. Comparison of the lava chemistry in the Dras–Kohistan Arc with that in the forearc turbidites suggests that these sediments are partially postcollisional, Jurutze Formation and not all pre-collisional Nindam Formation. Thus, the Dras–Eurasia collision can be dated as Turonian–Santonian (83.5–93.5 Ma), older than it was previously considered to be, but consistent with radiometric ages from Kohistan. 相似文献
12.
13.
历史地震图数据库及共享平台 总被引：1，自引：1，他引：0
历史地震图纸是记录历史地震的重要资料,在进行电子化之前,图纸的唯一性限制了其大范围共享的可能。电子化处理是抢救和保护历史地震图纸的重要手段,可以有效发挥其使用及研究价值,具有重要意义。为此研制历史地震图数据库及共享平台,对北京国家地球观象台现存的60万张历史地震图纸进行高精度(600 dpi)扫描和规则化命名,利用数据库和FastDFS分布式文件系统进行统一存储,并采用多级缩略图和网络服务方式提供数据共享服务。 相似文献
14.
It is indicated by historical records and the exploratory trench on the Weihe fault that the Yaodian-Zhangjiawan segment of the Weihe fault zone has experienced a historical earthquake and 3 paleoearthquake events in the past 9110a. The historical earthquake, namely, event Ⅳ, occurred between 1487 and 1568 AD. The date of paleoseismic event Ⅰ is （9110 ＋ 90） a, and the ages of events Ⅱ and Ⅲ are unknown. The coseismic vertical displacement of events Ⅰ, Ⅱ and Ⅲ is 0.5m, 0.5m and 0.2m, respectively. The exploratory trench also indicates that the Yaodian-Zhangjiawan segment of the Weihe fault was active in the Holocene. 相似文献
15.
《Journal of Geodynamics》2007,43(1):118-152
The large-scale volcanic lineaments in Iceland are an axial zone, which is delineated by the Reykjanes, West and North Volcanic Zones (RVZ, WVZ, NVZ) and the East Volcanic Zone (EVZ), which is growing in length by propagation to the southwest through pre-existing crust. These zones are connected across central Iceland by the Mid-Iceland Belt (MIB). Other volcanically active areas are the two intraplate belts of Öræfajökull (ÖVB) and Snæfellsnes (SVB). The principal structure of the volcanic zones are the 30 volcanic systems, where 12 are comprised of a fissure swarm and a central volcano, 7 of a central volcano, 9 of a fissure swarm and a central domain, and 2 are typified by a central domain alone.Volcanism in Iceland is unusually diverse for an oceanic island because of special geological and climatological circumstances. It features nearly all volcano types and eruption styles known on Earth. The first order grouping of volcanoes is in accordance with recurrence of eruptions on the same vent system and is divided into central volcanoes (polygenetic) and basalt volcanoes (monogenetic). The basalt volcanoes are categorized further in accordance with vent geometry (circular or linear), type of vent accumulation, characteristic style of eruption and volcanic environment (i.e. subaerial, subglacial, submarine).Eruptions are broadly grouped into effusive eruptions where >95% of the erupted magma is lava, explosive eruptions if >95% of the erupted magma is tephra (volume calculated as dense rock equivalent, DRE), and mixed eruptions if the ratio of lava to tephra occupy the range in between these two end-members. Although basaltic volcanism dominates, the activity in historical time (i.e. last 11 centuries) features expulsion of basalt, andesite, dacite and rhyolite magmas that have produced effusive eruptions of Hawaiian and flood lava magnitudes, mixed eruptions featuring phases of Strombolian to Plinian intensities, and explosive phreatomagmatic and magmatic eruptions spanning almost the entire intensity scale; from Surtseyan to Phreatoplinian in case of “wet” eruptions and Strombolian to Plinian in terms of “dry” eruptions. In historical time the magma volume extruded by individual eruptions ranges from ∼1 m3 to ∼20 km3 DRE, reflecting variable magma compositions, effusion rates and eruption durations.All together 205 eruptive events have been identified in historical time by detailed mapping and dating of events along with extensive research on documentation of eruptions in historical chronicles. Of these 205 events, 192 represent individual eruptions and 13 are classified as “Fires”, which include two or more eruptions defining an episode of volcanic activity that lasts for months to years. Of the 159 eruptions verified by identification of their products 124 are explosive, effusive eruptions are 14 and mixed eruptions are 21. Eruptions listed as reported-only are 33. Eight of the Fires are predominantly effusive and the remaining five include explosive activity that produced extensive tephra layers. The record indicates an average of 20–25 eruptions per century in Iceland, but eruption frequency has varied on time scale of decades. An apparent stepwise increase in eruption frequency is observed over the last 1100 years that reflects improved documentation of eruptive events with time. About 80% of the verified eruptions took place on the EVZ where the four most active volcanic systems (Grímsvötn, Bárdarbunga–Veidivötn, Hekla and Katla) are located and 9%, 5%, 1% and 0.5% on the RVZ–WVZ, NVZ, ÖVB, and SVB, respectively. Source volcano for ∼4.5% of the eruptions is not known.Magma productivity over 1100 years equals about 87 km3 DRE with basaltic magma accounting for about 79% and intermediate and acid magma accounting for 16% and 5%, respectively. Productivity is by far highest on the EVZ where 71 km3 (∼82%) were erupted, with three flood lava eruptions accounting for more than one half of that volume. RVZ–WVZ accounts for 13% of the magma and the NWZ and the intraplate belts for 2.5% each. Collectively the axial zone (RVZ, WVZ, NVZ) has only erupted 15–16% of total magma volume in the last 1130 years. 相似文献
16.
Three methods, Shuffled Complex Evolution (SCE), Simple Genetic Algorithm (SGA) and Micro‐Genetic Algorithm (µGA), are applied in parameter calibration of a grid‐based distributed rainfall–runoff model (GBDM) and compared by their performances. Ten and four historical storm events in the Yan‐Shui Creek catchment, Taiwan, provide the database for model calibration and verification, respectively. The study reveals that the SCE, SGA and µGA have close calibration results, and none of them are superior with respect to all the performance measures, i.e. the errors of time to peak, peak discharge and the total runoff volume, etc. The performances of the GBDM for the verification events are slightly worse than those in the calibration events, but still quite satisfactory. Among the three methods, the SCE seems to be more robust than the other two approaches because of the smallest influence of different initial random number seeds on calibrated model parameters, and has the best performance of verification with a relatively small number of calibration events. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
17.
ABSTRACTWeather generators rely on historical meteorological records to simulate time series of synthetic weather sequences, the quality of which has direct influence on model applications. The climate generator CLIGEN’s database has recently been updated to comprise consistent historical records from 1974 to 2013 (updated CLIGEN database, UCD) compared to the current database in which records are of different lengths. In this study, CLIGEN’s performance in estimating precipitation using UCD (eight stations) and the subsequent impact on urban runoff simulations (371 stations) were evaluated in the Great Lakes Region, USA. Generally, UCD-based precipitation could replicate observed daily precipitation up to the 99.5th percentile, but maximum precipitation was underestimated. Results from the Long-Term Hydrologic Impact Assessment model using UCD-based precipitation showed about 0.57 billion cubic meters more (14.9%) average annual runoff being simulated compared with simulations based on the current CLIGEN database. Overall, CLIGEN with the updated database was found suitable for providing precipitation estimates and for use with modeling urban runoff or urbanization effects. 相似文献
18.
长白山火山的历史与演化 总被引：3，自引：0，他引：3
长白山火山跨越中朝两国,在我国境内包括天池火山、望天鹅火山、图们江火山和龙岗火山,火山活动从上新世持续到近代,是我国最大的第四纪火山分布区。长白山火山的母岩浆是钾质粗面玄武岩,将长白山火山岩区称钾质粗面玄武岩省,岩浆结晶分异作用和混合作用主导了岩浆演化过程。天池火山之下地壳岩浆房和地幔岩浆房具双动式喷发特点,一方面来自地幔的钾质粗厨玄武岩浆直接喷出地表;另一方面钾质粗面玄武岩浆持续补给地壳岩浆房,发生岩浆分离结晶作用和混合作用,导致双峰式火山岩分布特征和触发千年大喷发。西太平洋板块俯冲-东北亚大陆弧后引张是长白山火山活动的动力学机制。 相似文献
19.
Asymmetric back-arc spreading, heat flux and structure associated with the Central Volcanic Region of New Zealand 总被引：1，自引：0，他引：1
T.A. Stern 《Earth and Planetary Science Letters》1987,85(1-3)
The Central Volcanic Region of New Zealand is an active back-arc basin developed within continental lithosphere, and therefore offers a rare opportunity to study back-arc extension from land-based observations. Two parameters related to the heat output from the Central Volcanic Region are of particular interest. Firstly, the average heat flow for the eastern half of the Central Volcanic Region is about 800 mW/m2—in order to maintain this heat flow over geological time periods an efficient mass-transfer of heat is required. Secondly, the observed asymmetry in the pattern of heat output, coupled with the tectonic erosion of blocks of continental crust from the eastern axial ranges into the Central Volcanic Region, suggests that the process currently in progress at the eastern margin of the Region is asymmetric spreading with concomitant thermal differentiation of continental crust into its silicic and basic components. 相似文献
20.
南黄海地区的地震活动特征与趋势 总被引：1，自引：0，他引：1
概述了南黄海地区的地震活动性，介绍了该海区历史地震的分布，时空强特征以及众多地震事件烈度分布的共同特点与地震活动规律等。研究表明，功北南黄海地区近年内存在发生较强地震的危险性。 相似文献