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1.
以当代火山物理的观点和思路对黑龙江省五大连池老黑山烧山进行了研究，在旧锥锥体上部发现滞后角砾岩，在其下部坡脚发现有涌浪堆积物的存在，对形成过程和机制做了一些解释。 相似文献
3.
长白山天池火山潜在喷发危险性讨论 总被引：3，自引：0，他引：3
根据吉林省新生代以来火山喷溢活动的时空演化历史，特别是全新世以来火山活动频民强度变化特征，以及现代喷发活动史记资料，结合１０多年火山动态观测数据，讨论了长白山天池潜在喷发的危险程度，认为其灾害性潜在喷发危险的时间尺度仍属于地质范畴。 相似文献
4.
新疆独山子泥火山喷发特征的研究 总被引：8，自引：0，他引：8
新疆独山子泥火山喷发特征的研究李锰，王道，李茂伟，戴晓敏（新疆维吾尔自治区地震局．乌鲁木齐，８３００１１）１９９５年８月３日，伊犁哈萨克自治州地震办公室李凡德报告，独山子泥火山近期喷发，达尔庙２９号井水位出现异常。为此新疆维吾尔自治区地震局派出工作组... 相似文献
5.
望天鹅火山位于吉林省长白县中部,距长白山天池火山35km.据《朝鲜王朝实录》中记载,1597年10月6日在朝鲜咸镜道三水郡小农堡越边北发生火山喷发.文中据朝鲜地方志和古地图等资料,对史料作历史地理考证,提出1597年10月6日火山喷发发生在望天鹅火山底部,地点在今吉林省长白县十三道沟村与十四道沟镇之间的山岭,距望天鹅火山主峰约30km,距长白山天池约60km. 相似文献
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7.
五大连池火山喷发史料研究概述 总被引：2，自引：0，他引：2
“五大连池近代火山喷发史料发掘考察与研究”课题是中国地震局地震科学联合基金资助的课题(编号：100155,成果登记号：中震科登字2002010J)。该项研究取得了突破性的成果。首次在280多年前的清代黑龙江将军衙门满文档案中发现珍藏有五 相似文献
8.
腾冲火山地热区的构造演化与火山喷发 总被引：7，自引：0，他引：7
讨论了腾冲地区在Ｄ－Ｅ２时期的板块拼合演化过程及其大地构造单元位置，用以说明腾冲火山地热区的现今区域构造条件，讨论了火山喷发时期与板块碰撞时代的关系。 相似文献
9.
长白山天池火山喷发的气候效应 总被引：5，自引：0，他引：5
约发生于１０００年前的长白山天池火山喷发对全球气候产生过非常显著的影响，本文用一二维能量平衡模式模拟了天地火山的那次喷发对全球气候的影响。结果表明：天池火山喷发形成的平流层气溶胶可维持３年长的时间，并对到达地表的太阳辐射有非常明显的削弱。引起的北半球平均最大降温可达０．８５℃。天池火山大喷发对全球气候影响的时间超过６年。 相似文献
10.
存于黑龙江将军衙门档案中的五大连池火山喷发满文史料 (由吴雪娟发现并译成汉文 ) ,详细记载了五大连池火山在 172 0年 1月 14日至 172 1年 3月 18日喷发形成老黑山、172 1年 4月 2 6日至 172 1年 5月 2 8日喷发形成火烧山的全部过程 ,记述了这 2座火山的喷发时间、地点、喷发状态和火山堰塞湖形成以及参加观测的人员情况等各种史实。这是中国历史上迄今为止对火山喷发仅有的一次有组织的观测活动 ,这些记录为火山观测研究提供了珍贵的第一手资料。同时 ,也表明中国是世界上火山观测开展较早的国家之一。以往认为五大连池老黑山、火烧山火山喷发的时间为公元1719— 172 1年 ,实际应为公元 172 0— 172 1年 相似文献
11.
Alexander Garcia-Aristizabal Hiroyuki Kumagai Pablo Samaniego Patricia Mothes Hugo Yepes Michel Monzier 《Journal of Volcanology and Geothermal Research》2007
Guagua Pichincha, located 14 km west of Quito, Ecuador, is a stratovolcano bisected by a horseshoe-shaped caldera. In 1999, after some months of phreatic activity, Guagua Pichincha entered into an eruptive period characterized by the extrusion of several dacitic domes, vulcanian eruptions, and pyroclastic flows. We estimated the three-dimensional (3-D) P-wave velocity structure beneath Guagua Pichincha using a tomographic inversion method based on finite-difference calculations of first-arrival times. Hypocenters of volcano-tectonic (VT) earthquakes and long-period (LP) events were relocated using the 3-D P-wave velocity model. A low-velocity anomaly exists beneath the caldera and may represent an active volcanic conduit. Petrologic analysis of eruptive products indicates a magma storage region beneath the caldera, having a vertical extent of 7–8 km with the upper boundary at about sea level. This zone coincides with the source region of deeper VT earthquakes, indicating that a primary magma body exists in this region. LP swarms occurred in a cyclic pattern synchronous with ground deformation during magma extrusions. The correlation between seismicity and ground deformation suggests that both respond to pressure changes caused by the cyclic eruptive behavior of lava domes. 相似文献
12.
We investigate the origin of diversity of eruption styles in silicic volcanoes on the basis of a 1-dimensional steady conduit flow model that considers vertical relative motion between gas and liquid (i.e., vertical gas escape). The relationship between the assemblage of steady-state solutions in the conduit flow model and magma properties or geological conditions is expressed by a regime map in the parameter space of the ratio of liquid-wall friction force to liquid–gas interaction force (non-dimensional number ε), and a normalized conduit length Λ. The regime map developed in the companion paper shows that when ε is smaller than a critical value εcr, a solution of explosive eruption exists for a wide range of Λ, whereas an effusive solution exists only when Λ ~ 1. On the other hand, when ε > εcr, an effusive solution exists for a wide range of Λ. Diversity of eruption styles observed in nature is explained by the change in ε accompanied by the change in magma viscosity during magma ascent. As magma ascends, the magma viscosity increases because of gas exsolution and crystallization, leading to the increase in ε. For the viscosity of hydrous silicic magma at magma chamber, ε is estimated to be smaller than εcr, indicating that an explosive solution exists for wide ranges of geological parameters. When magma flow rate is small, the viscosity of silicic magma drastically increases because of extensive crystallization at a shallow level in the conduit. In this case, ε can be greater than εcr; as a result, a stable effusive solution co-exists with an explosive solution. 相似文献
13.
Akira Takada 《Bulletin of Volcanology》1997,58(7):539-556
Many basaltic and andesitic polygenetic volcanoes have cyclic eruptive activity that alternates between a phase dominated
by flank eruptions and a phase dominated by eruptions from a central vent. This paper proposes the use of time-series diagrams
of eruption sites on each polygenetic volcano and intrusion distances of dikes to evaluate volcano growth, to qualitatively
reconstruct the stress history within the volcano, and to predict the next eruption site. In these diagrams the position of
an eruption site is represented by the distance from the center of the volcano and the clockwise azimuth from north. Time-series
diagrams of Mauna Loa, Kilauea, Kliuchevskoi, Etna, Sakurajima, Fuji, Izu-Oshima, and Hekla volcanoes indicate that fissure
eruption sites of these volcanoes migrated toward the center of the volcano linearly, radially, or spirally with damped oscillation,
occasionally forming a hierarchy in convergence-related features. At Krafla, terminations of dikes also migrated toward the
center of the volcano with time. Eruption sites of Piton de la Fournaise did not converge but oscillated around the center.
After the convergence of eruption sites with time, the central eruption phase is started. The intrusion sequence of dikes
is modeled, applying crack interaction theory. Variation in convergence patterns is governed by the regional stress and the
magma supply. Under the condition that a balance between regional extension and magma supply is maintained, the central vent
convergence time during the flank eruption phase is 1–10 years, whereas the flank vent recurrence time during the central
eruption phase is greater than 100 years owing to an inferred decrease in magma supply. Under the condition that magma supply
prevails over regional extension, the central vent convergence time increases, whereas the flank vent recurrence time decreases
owing to inferred stress relaxation. Earthquakes of M≥6 near a volcano during the flank eruption phase extend the central
vent convergence time. Earthquakes during the central eruption phase promote recurrence of flank eruptions. Asymmetric distribution
of eruption sites around the flanks of a volcano can be caused by local stress sources such as an adjacent volcano.
Received: 18 March 1996 / Accepted: 14 January 1997 相似文献
14.
The 3-month long eruption of Asama volcano in 1783 produced andesitic pumice falls, pyroclastic flows, lava flows, and constructed a cone. It is divided into six episodes on the basis of waxing and waning inferred from records made during the eruption. Episodes 1 to 4 were intermittent Vulcanian or Plinian eruptions, which generated several pumice fall deposits. The frequency and intensity of the eruption increased dramatically in episode 5, which started on 2 August, and culminated in a final phase that began on the night of 4 August, lasting for 15 h. This climactic phase is further divided into two subphases. The first subphase is characterized by generation of a pumice fall, whereas the second one is characterized by abundant pyroclastic flows. Stratigraphic relationships suggest that rapid growth of a cone and the generation of lava flows occurred simultaneously with the generation of both pumice falls and pyroclastic flows. The volumes of the ejecta during the first and second subphases are 0.21 km3 (DRE) and 0.27 km3 (DRE), respectively. The proportions of the different eruptive products are lava: cone: pumice fall=84:11:5 in the first subphase and lava: cone: pyroclastic flow=42:2:56 in the second subphase. The lava flows in this eruption consist of three flow units (L1, L2, and L3) and they characteristically possess abundant broken phenocrysts, and show extensive "welding" texture. These features, as well as ghost pyroclastic textures on the surface, indicate that the lava was a fountain-fed clastogenic lava. A high discharge rate for the lava flow (up to 106 kg/s) may also suggest that the lava was initially explosively ejected from the conduit. The petrology of the juvenile materials indicates binary mixing of an andesitic magma and a crystal-rich dacitic magma. The mixing ratio changed with time; the dacitic component is dominant in the pyroclasts of the first subphase of the climactic phase, while the proportion of the andesitic component increases in the pyroclasts of the second subphase. The compositions of the lava flows vary from one flow unit to another; L1 and L3 have almost identical compositions to those of pyroclasts of the first and second subphases, respectively, while L2 has an intermediate composition, suggesting that the pyroclasts of the first and second subphases were the source of the lava flows, and were partly homogenized during flow. The complex features of this eruption can be explained by rapid deposition of coarse pyroclasts near the vent and the subsequent flowage of clastogenic lavas which were accompanied by a high eruption plume generating pumice falls and/or pyroclastic flows.Editorial responsibility: T. Druitt 相似文献
15.
The first sign of magma accumulating beneath Miyakejima, an island volcano in the northern Izu islands, Japan, came at around 18:00 on 26 June 2000, when a swarm of earthquakes was detected by a volcano seismic network on the island. Earthquakes occurred initially beneath the southwest flank near the summit and gradually migrated west of the island, where a submarine eruption occurred the next morning. Earthquakes then migrated further to the northwest between Miyakejima and Kozushima, another volcanic island and developed to the most intense earthquake swarm ever observed in and around Japanese archipelago. To better image how the initial magma intrusion occurred, we relocated hypocenters by using a station-correction method and a double-difference method. The relocated epicenters are generally concentrated near the upper bound of dyke intrusions inferred from geodetic studies throughout the initial stages of the 2000 eruption at Miyakejima from 26 to 27 June 2000. As for seismic activity westward off Miyakejima in the morning on 27 June, hypocenters from both a nationwide seismic network that were relocated by the double-difference method, and those from the volcano seismic network relocated by the station-correction method, formed a very shallow cluster that ascended slowly with time as it propagated northwestward from Miyakejima. This suggests that the dykes have both a radial and upward component of movement.Editorial responsibility: S. Nakada, T. Druitt 相似文献
16.
R. Cioni A. Bertagnini R. Santacroce D. Andronico 《Journal of Volcanology and Geothermal Research》2008
A new proposal for the classification of Somma-Vesuvius (SV) explosive activity is presented, based on a critical revision of a large set of published and unpublished stratigraphic, compositional, and physical volcanology data on the products of the past 20,000 years of activity. The new database is used to discuss the general behaviour of the volcano in terms of frequency, magnitude and intensity of the events, as well as of the length of the repose time which preceded each eruption. Several different types of eruption are recognized, each characterised by specific physical eruptive parameters: plinian, subplinian (further subdivided in subplinian I and subplinian II), violent strombolian, ash emission events. For each eruption type, a complex scenario is described, with phases of different style, duration, magnitude and intensity occurring during the course of the eruption itself. The name given to each eruption type is derived from the style of the most representative part of the eruption (in terms of duration or volume). 相似文献
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18.
B. Voight K. D. Young D. Hidayat Subandrio M. A. Purbawinata A. Ratdomopurbo Suharna Panut D. S. Sayudi R. LaHusen J. Marso T. L. Murray M. Dejean M. Iguchi K. Ishihara 《Journal of Volcanology and Geothermal Research》2000,100(1-4)
Following the eruption of January 1992, episodes of lava dome growth accompanied by generation of dome-collapse nuées ardentes occurred in 1994–1998. In addition, nuées ardentes were generated by fountain-collapse in January 1997, and the 1998 events also suggest an explosive component. Significant tilt and seismic precursors on varying time scales preceded these events. Deformation about the summit has been detected by electronic tiltmeters since November 1992, with inflation corresponding generally to lava dome growth, and deflation (or decreased inflation) corresponding to loss of dome mass. Strong short-term (days to weeks) accelerations in tilt rate and seismicity occurred prior to the major nuées ardentes episodes, apart from those of 22 November 1994 which were preceded by steadily increasing tilt for over 200 days but lacked short-term precursors. Because of the combination of populated hazardous areas and the lack of an issued warning, about 100 casualties occurred in 1994. In contrast, the strong precursors in 1997 and 1998 provided advance warning to observatory scientists, enabled the stepped raising of alert levels, and aided hazard management. As a result of these factors, but also the fortunate fact that the large nuées ardentes did not quite descend into populated areas, no casualties occurred. The nuée ardente episode of 1994 is interpreted as purely due to gravitational collapse, whereas those of 1997 and 1998 were influenced by gas-pressurization of the lava dome. 相似文献
19.
Akihiko Fujinawa Masao Ban Tsukasa Ohba Kazuo Kontani Kotaro Miura 《Journal of Volcanology and Geothermal Research》2008
Three eruption events occurring in the central part of the northeastern Japan arc were investigated and compared: Adatara AD1900, Zao AD1895, and Bandai AD1888. Producing low-temperature (LT) pyroclastic surges, these events are characterized by steam eruptions ejecting no juvenile material. These eruptions' well-preserved eruptive deposits and facies facilitated granulometric analyses of the beds, which revealed the transport and deposition mechanisms of LT surges. Combining these results with those of investigations of documents reporting the events, we correlated each eruption to the relevant individual bed and reconstructed the LT surge development sequence. Important findings related to the transport and deposition modes are the following. (1) Bed sets consisting of thin, laminated ash and its overlying thick massive tuff were recognized in the Adatara 1900 proximal deposits. The bed set was probably produced by a strong wind that discharged and propagated quickly from the vent (leading wind) and a gravitationally segregated, highly concentrated flow originated from the eruption column, within a discrete eruption episode. A similar combination might have occurred during the first surge of the Bandai 1888 event. (2) Comparison of the proximal and distal facies for the largest eruption of Adatara 1900 event indicates that the initial turbulence of the eruption cloud decreased rapidly, transforming into a density-stratified surge with a highly concentrated part near the base. Similar surges occurred in the climatic stage of Zao 1895. (3) Bandai 1888 ejecta indicate massive beds deposited preferentially at topographic lows. Co-occurring planar beds showed no topographic affection, as indicated by the topographic blocking of a stratified surge. The observed facies–massive tuffs, crudely stratified tuffs, and thin bedded tuffs–are compatible with those for high-temperature surges. At Bandai, absence of dune bedded tuffs and commonly poorer sorting in the LT surge deposits might be attributable to poor thermally induced turbulence of eruption columns. Condensation of vapor in the surges might have contributed to the poor sorting. The estimated explosion energies were 6 × 1013 J for Adatara AD1900, 6.5 × 1010 J for Zao AD1895, and 6.5 × 1015 J for Bandai AD1888, implying that the three events were hydrothermal eruptions with distinctive eruptive mechanisms. Regarding eruption sources, the Adatara 1900 event was caused solely by thermal energy of the hydrothermal fluid, although magma intrusion likely triggered evolution of hydrothermal systems at Zao in 1895. Steam eruptions in the Bandai 1888 event occurred simultaneously with sudden exposure of the hydrothermal system, whose triggers require no internal energy. 相似文献
20.
The Ezine region is located in the northwestern part of Anatolia where young granitic and volcanic rocks are widespread and show close spatial and temporal association. In this region magmatism began with the Kestanbol granite, which intruded into metamorphic basement rocks, and formed contact metamorphic aureole. To the east and southeast the pluton is surrounded by hypabyssal rocks, which in turn, are surrounded by volcanic associations. The volcanic rocks may be divided into two main groups on the basis of their lithological properties. Lavas and lahar deposits dominate the northern sector while ignimbrites dominate the southern sector. The ignimbrite eruptions were formed partly coevally with the plutonic and the associated volcanic rocks during the early Miocene. They appear to have been associated in a caldera collapse environment. Geochemical properties of the plutonic and the associated volcanic assemblages indicate that the magmas are hybrid and co-genetic and, were formed from a similar mantle source, under a compressional regime prior to the opening of the present E–W-trending graben of the Aegean western Anatolian region. 相似文献