共查询到20条相似文献，搜索用时 15 毫秒
1.
Explosive volcanic eruptions are known to be a leading cause of natural climate change. There has been a growing recognition that there is a measurable climate system response even to moderate-sized volcanic eruptions. In this study, we investigated the hindcast skills of the Pacific Sea Surface Temperatures (SSTs) using the hindcast experiments based on the near-term climate prediction system DecPreS developed by the Institute of Atmospheric Physics (IAP)(hereafter DP-EnOI-IAU experiments). The DP-EnOI-IAU experiments were run for initial years from 1960 to 2005. These hindcasts took into account observed stratospheric aerosol concentrations that included the four large tropical volcanic eruptions during that period. The time evolution over the entire hindcast period for skill in predicting the patterns of the 3~7 year prediction averages for Pacific SSTs showed that there was statistically significant skill for most years except for a dramatic drop in skill during the 1980s and 1990s. Decadal hindcast skill is reduced if the post-eruption model response deviates the internal El Niño variability in the observations. The simulations showed a post-eruption SST of a La Niña-like pattern in the third northern winter after the 1982 El Chichon eruption and a El Niño-like pattern after the 1991 Pinatubo eruption, which were opposite in sign to what was in the observations. This lead to the loss of hindcast skill for years in the 1980s and 1990s affected by the eruptions. Agung (1963) happened to have post-eruption Pacific SSTs more similar to the observations and thus did not degrade prediction skill in the hindcasts. 相似文献
2.
《Applied Geochemistry》1995,10(2):215-227
Some experiences obtained in Mexico pursuing the identification of geochemical precursors and changes associated to different kinds of volcanic activity are discussed. Three recent events of volcanic unrest are described in the context of an active geological environment. The identification of some geochemical precursors helped to evaluate the eruptive potential during two volcanic crises (Tacana´, 1986; Colima, 1991). The significant compositional fluctuations observed after a volcanic catastrophic eruption (El Chichon, 1982) are also discussed. It is concluded that even simple geochemical methods may provide a useful tool for the evaluation of the level of activity and the recognition of some eruption precursors. 相似文献
3.
D. Metzner S. Kutterolf M. Toohey C. Timmreck U. Niemeier A. Freundt K. Krüger 《International Journal of Earth Sciences》2014,103(7):2063-2079
We present for the first time a self-consistent methodology connecting volcanological field data to global climate model estimates for a regional time series of explosive volcanic events. Using the petrologic method, we estimated SO2 emissions from 36 detected Plinian volcanic eruptions occurring at the Central American Volcanic Arc (CAVA) during the past 200,000 years. Together with simple parametrized relationships collected from past studies, we derive estimates of global maximum volcanic aerosol optical depth (AOD) and radiative forcing (RF) describing the effect of each eruption on radiation reaching the Earth’s surface. In parallel, AOD and RF time series for selected CAVA eruptions are simulated with the global aerosol model MAECHAM5-HAM, which shows a relationship between stratospheric SO2 injection and maximum global mean AOD that is linear for smaller volcanic eruptions (<5 Mt SO2) and nonlinear for larger ones (≥5 Mt SO2) and is qualitatively and quantitatively consistent with the relationship used in the simple parametrized approximation. Potential climate impacts of the selected CAVA eruptions are estimated using an earth system model of intermediate complexity by RF time series derived by (1) directly from the global aerosol model and (2) from the simple parametrized approximation assuming a 12-month exponential decay of global AOD. We find that while the maximum AOD and RF values are consistent between the two methods, their temporal evolutions are significantly different. As a result, simulated global maximum temperature anomalies and the duration of the temperature response depend on which RF time series is used, varying between 2 and 3 K and 60 and 90 years for the largest eruption of the CAVA dataset. Comparing the recurrence time of eruptions, based on the CAVA dataset, with the duration of climate impacts, based on the model results, we conclude that cumulative impacts due to successive eruptions are unlikely. The methodology and results presented here can be used to calculate approximate volcanic forcings and potential climate impacts from sulfur emissions, sulfate aerosol or AOD data for any eruption that injects sulfur into the tropical stratosphere. 相似文献
4.
Concentrations of the members of the 238U decay chain and 232Th were determined in volcanic rocks from convergent plate margins, intraplate volcanoes and oceanic spreading centers. Contemporary and historical volcanic rocks from Mt. St. Helens, Arenal, El Chichon, Hawaii and Iceland and submarine basaltic glass from the Galapagos spreading center all show no fractionation of U and Th in the mantle source or during magma formation at least for the past 300,000 years. Mauna Kea (Hawaii) rocks of alkaline composition greater than 4000 years old and an old submarine basalt show disequilibrium for several of the nuclides in the 238U decay chain. We interpret these as resulting from post-emplacement processes. 相似文献
5.
硅质火山喷发作为大陆地壳岩浆活动的重要表现，在研究大陆地壳形成与演化、探讨岩浆过程与动力学机制等方面具有重要的价值，其通常所表现的强烈爆炸式喷发，甚至可以导致全球性的环境和气候变迁。硅质岩浆系统在开放体系中不同来源岩浆的贡献和相互作用是目前研究的热点问题。持续的岩浆补给可以延长岩浆存储的时间，促进岩浆房的对流、岩浆的分异演化以及晶体 熔体的分离和晶粥的再活化，同时也是触发火山喷发的重要机制之一。此外，岩浆补给以及硅质岩浆的晶体 熔体演化过程也是火山喷发产物多样性的原因，导致同一火山在其活动过程中喷发产物规律性的变化，如富晶体火山岩、贫晶体火山岩、火山岩成分分层、以及复活岩穹和中央侵入体等。因此，岩浆补给作用是制约硅质火山岩浆系统演化和火山岩成分多样性的重要因素，也是活动火山监测和灾害评估的重要依据。岩石学、岩石地球化学、矿物(长石、石英、石榴子石、锆石等)同位素及成分变化，以及模拟实验、地震层析成像等研究为揭示硅质岩浆系统中的岩浆补给作用和复杂岩浆过程提供了多种视角。 相似文献
6.
With respect to atmospheric impact, the 1982 eruption of the El Chichón volcano in Mexico is one of the most significant volcanic events of this century. The presence in the stratosphere, during several years, of an unusally high amount of sulfuric acid aerosols produced by this eruption is thought to be responsible for severe windshield damages on high-flying commercial jets. This problem took epidemic proportions in 1983–1984 and the cost to commercial aviation companies is estimated at several tens of millions of U.S. dollars. 相似文献
7.
Rolando P. Orense Andrew Zapanta Jr. Akinori Hata Ikuo Towhata 《Geotechnical and Geological Engineering》2006,24(1):129-161
Recent volcanic eruptions at Mt. Unzen (Japan) in 1990 and Mt. Pinatubo (Philippines) in 1991 produced voluminous amounts
of ash and sediments which inundated widespread areas. In later rehabilitation and reconstruction, it is practical and economical
to use these freshly deposited sediments as materials for foundations and embankments. However, the geotechnical properties
of young volcanic products have not been fully investigated. Accordingly, we investigated the geotechnical characteristics
of volcanic soils associated with three recent eruptions, namely, the Unzen and Izu-Oshima eruptions of 1990 and 1986, respectively,
in Japan and the Pinatubo eruption of 1991 in the Philippines. We specifically investigated index properties, permeability
and compaction characteristics, and strength and deformation behavior in drained conditions. Additionally, we examined the
dynamic properties and liquefaction characteristics of samples taken from Mt. Pinatubo. The results showed that the geotechnical
characteristics of the deposits generally varied with the sampling sites. Depending on the location, either upstream or downstream
from a volcano, the preferential sizing due to alluvial deposition affects engineering properties of the deposits. For example,
volcanic sediments upstream from Mt. Pinatubo have high compressibility and low cyclic strength, whereas those taken downstream
show dilative tendencies and high liquefaction strength. 相似文献
8.
With respect to atmospheric impact, the 1982 eruption of the El Chichón volcano in Mexico is one of the most significant volcanic events of this century. The presence in the stratosphere, during several years, of an unusally high amount of sulfuric acid aerosols produced by this eruption is thought to be responsible for severe windshield damages on high-flying commercial jets. This problem took epidemic proportions in 1983–1984 and the cost to commercial aviation companies is estimated at several tens of millions of U.S. dollars. 相似文献
9.
ANDREAS WETZEL 《Sedimentology》2009,56(7):1992-2009
Following the eruption of Mount Pinatubo on 15 June 1991, volcanic ash was transported westward to the South China Sea in an atmospheric plume, falling out and settling to the sea floor within days and forming an up to 10 cm thick layer on an area >400 000 km2. Immediately after deposition, surviving deep‐burrowing animals re‐opened their connection to the sea floor to obtain water for respiration and/or food take‐up. Later, small‐sized meiofauna and then macrofauna re‐colonized the sea floor, mixing newly deposited organic fluff with the underlying ash. Consequently, ash deposits thinner than 1 mm have not often been observed as a continuous layer when cored six years after the eruption, while ash about 2 mm thick is now patchily bioturbated. In areas covered by ash thicker than 5 mm, mixing by benthic animals is controlled mainly by the adaptation of the burrowing fauna to variations in grain‐size, the rate of background sedimentation, the availability of benthic food on and within the sediment and pore water oxygen levels. With respect to these factors, four provinces can be distinguished: (i) Along the Philippines margin run‐off from land fuels primary production that, in turn, leads to a high benthic food content. The benthic fauna is adapted to a variable grain‐size and rapid sedimentation. Therefore, mixing is intense and the preservation potential of the ash layer is low. (ii) In areas affected by deposition of hyperpycnites and turbidites, i.e. in canyons in front of river mouths and in the Manila Trench, the ash layer is preserved due to rapid burial. (iii) The area to the west to about 116° E receives low amounts of benthic food, benthic mixing is less intense and the preservation potential of the ash is high. (iv) The central South China Sea, where the ash is thinner than 3 cm, is affected by intense wind mixing and upwelling and the benthic food content is high; thus, the chance that the ash will be preserved as a sharp‐based layer is low. Consequently, the style of ash preservation has palaeo‐environmental significance. Older buried and burrowed event layers provide further information to elucidate the fate of the 1991 Pinatubo ash layer; in general their appearance fits with observations in the Recent. 相似文献
10.
A probabilistic eruption forecast is provided for seven historically active volcanoes along the Central American Volcanic Arc (CAVA), as a pivotal empirical contribution to multi-disciplinary volcanic hazards assessment. The eruption probabilities are determined with a Kaplan–Meier estimator of survival functions, and parametric time series models are applied to describe the historical eruption records. Aside from the volcanoes that are currently in a state of eruptive activity (Santa María, Fuego, and Arenal), the highest probabilities for eruptions of VEI ≥ 2 occur at Concepción and Cerro Negro in Nicaragua, which are likely to erupt to 70–85 % within the next 10 years. Poás and Irazú in Costa Rica show a medium to high eruption probability, followed by San Miguel (El Salvador), Rincón de la Vieja (Costa Rica), and Izalco (El Salvador; 24 % within the next 10 years). 相似文献
11.
R. K. R. Vupputuri 《Natural Hazards》1992,5(1):1-16
A coupled one-dimensional radiative-convective-photochemical diffusion model, which takes into account the influence of ocean inertia on global radiative perturbations is used to investigate the possible climatic and other atmospheric effects of a major volcanic eruption, thought to be similar in magnitude to that of the Tambora eruption, Indonesia, which took place in 1815. A volcanic cloud was introduced in the model stratosphere between 20–25 km and the global average peak aerosol optical thickness was assumed to be 0.25. Both the aerosol optical thickness and aerosol composition, which determine the optical properties, were allowed to vary in the model atmosphere during the life cycle of the volcanic cloud. The results indicate that the global average surface temperature decreases steadily from the date of eruption (7–12 April 1815) with maximum cooling of 1° K occurring in the spring of 1816. The calculations also show significant warming of the stratosphere, with temperature increasing up to 15° K at 25 km in less than six months after the date of eruption. The important effects of the Tambora eruption on stratospheric ozone and UV-B radiation at the surface are also mentioned. 相似文献
12.
13.
Nearly contemporaneous eruption of alkaline and calc-alkaline lavas occurred about 900 years BP from El Volcancillo paired vent, located behind the volcanic front in the Mexican Volcanic Belt (MVB). Emission of hawaiite (Toxtlacuaya) was immediately followed by calc-alkaline basalt (Río Naolinco). Hawaiites contain olivine microphenocrysts (Fo67–72), plagioclase (An56–60) phenocrysts, have 4–5 wt% MgO and 49.6–50.9 wt% SiO2. In contrast, calc-alkaline lavas contain plagioclase (An64–72) and olivine phenocrysts (Fo81–84) with spinel inclusions, and have 8–9 wt% MgO and 48.4–49.4 wt% SiO2. The most primitive lavas in the region (Río Naolinco and Cerro Colorado) are not as primitive as parental melts in other arcs, and could represent either (a) variable degrees of melting of a subduction modified, garnet-bearing depleted mantle source, followed by AFC process, or (b) melting of two distinct mantle sources followed by AFC processes. These two hypotheses are evaluated using REE, HFSE, and Sr, Os and Pb isotopic data. The Toxtlacuaya flow and the Y & I lavas can be generated by combined fractional crystallization and assimilation of gabbroic granulite, starting with a parental liquid similar to the Cerro Colorado basalt. Although calc-alkaline and alkaline magmas commonly occur together in other areas of the MVB, evidence for subduction component in El Volcancillo magmas is minimal and limited to <1%, which is a unique feature in this region further from the trench. El Volcancillo lavas were produced from two different magma batches: we surmise that the injection of calc-alkaline magma into an alkaline magma chamber triggered the eruption of hawaiites. Our results suggest that the subalkaline and hawaiitic lavas were formed by different degrees of partial melting of a similar, largely depleted mantle source, followed by later AFC processes. This model is unusual for arcs, where such diversity is usually explained by melting of heterogeneous (enriched and depleted) and subduction-modified mantle. 相似文献
14.
R. K. R. Vupputuri 《Natural Hazards》1984,5(1):1-16
A coupled one-dimensional radiative-convective-photochemical diffusion model, which takes into account the influence of ocean inertia on global radiative perturbations is used to investigate the possible climatic and other atmospheric effects of a major volcanic eruption, thought to be similar in magnitude to that of the Tambora eruption, Indonesia, which took place in 1815. A volcanic cloud was introduced in the model stratosphere between 20–25 km and the global average peak aerosol optical thickness was assumed to be 0.25. Both the aerosol optical thickness and aerosol composition, which determine the optical properties, were allowed to vary in the model atmosphere during the life cycle of the volcanic cloud. The results indicate that the global average surface temperature decreases steadily from the date of eruption (7–12 April 1815) with maximum cooling of 1° K occurring in the spring of 1816. The calculations also show significant warming of the stratosphere, with temperature increasing up to 15° K at 25 km in less than six months after the date of eruption. The important effects of the Tambora eruption on stratospheric ozone and UV-B radiation at the surface are also mentioned. 相似文献
15.
本文分析得到:1957—1982年间,全球低纬度火山爆发有73.9％和高纬度火山爆发有62.5％,分别发生在地球自转年际变化的减速段和加速段;火山爆发的日期,一般多发生在3天内遇到3个以上天文奇点引潮力共振加压的叠加之时,强火山爆发都发生在4个以上此种共振加压之时。表明地球自转速度变化和天文奇点引潮力共振加压在不同时间尺度上,分别对火山爆发具有调制和触发作用。其物理机理,两者都是引起火山附近地壳异常加压,促使岩浆受到挤压而累积能量或触发爆发。 相似文献
16.
黑龙江西北部小古里河过钾质基性、超基性火山岩的发现 总被引：3，自引：1，他引：2
本文报道了黑龙江省五大连池裂谷带北端出露的一套超基性、基性的过钾质火山岩,通过详细的野外调查,确认了火山岩的喷发顺序,肯定了火山岩从基性岩向超基性岩的演变以及它们的K_2O、TiO_2含量不断提高的事实.在此基础上作者对超基性-过钾质岩石的岩浆成因提出了初步认识,认为它们不是岩浆结晶分异作用的产物,而是在裂谷演化构造背景下的一次独立的深源岩浆事件.本文将小古里河的过钾质火山岩和乌干达及意大利等世界上著名的钾质火山岩进行了比较. 相似文献
17.
Andrea Cannata Gaetano Giudice Sergio Gurrieri Placido Montalto Salvatore Alparone Giuseppe Di Grazia Rocco Favara Stefano Gresta Marco Liuzzo 《Environmental Earth Sciences》2010,61(3):477-489
Large variations of the CO2 flux through the soil were observed between November 2002 and January 2006 at Mt. Etna volcano. In many cases, the CO2 flux was strongly influenced by changes in air temperature and atmospheric pressure. A new filtering method was then developed
to remove the atmospheric influences on soil CO2 flux and, at the same time, to highlight the variations strictly related to volcanic activity. Successively, the CO2 corrected data were quantitatively compared with the spectral amplitude of the volcanic tremor by cross correlation function,
cross-wavelet spectrum and wavelet coherence. These analyses suggested that the soil CO2 flux variations preceded those of volcanic tremor by about 50 days. Given that volcanic tremor is linked to the shallow (a
few kilometer) magma dynamics and soil CO2 flux related to the deeper (~12 km b.s.l.) magma dynamics, the “delayed similarity” between the CO2 flux and the volcanic tremor amplitude was used to assess the average speed in the magma uprising into the crust, as about
170–260 m per day. Finally, the large amount of CO2 released before the onset of the 2004–2005 eruption indicated a deep ingression of new magma, which might have triggered
such an eruption. 相似文献
18.
吉林省龙岗火山群南龙湾第四纪火山碎屑颗粒特征研究 总被引：2，自引：0，他引：2
爆炸性火山喷发形成的碎屑颗粒的粒度、分选性、表面结构和内部结构等特征与火山喷发的机制、岩浆与水作用的程度、搬运过程等有着重要的联系。本文以此为线索,研究了龙岗火山群南龙湾火山的一个剖面,以探讨其喷发类型和特征。在该剖面上采集了不同层位火山碎屑颗粒样品,然后进行显微形貌观测、粒度分析和扫描电镜形貌观测。显微镜下观测表明,射汽爆发、射汽岩浆爆发和岩浆爆发的碎屑颗粒具有不同的成分和形貌特征。粒度分析结果显示,粒度与喷发类型之间存在很好的对应关系,不同的爆发类型具有不同的分维值D范围。SEM分析可以提供有关火山喷发特征对火山碎屑颗粒的影响。本文的研究结果表明,南龙湾火山喷发为爆炸式喷发,包括早期的射汽岩浆爆发,到岩浆爆发至晚期以射汽爆发为主的射汽岩浆爆发的不同阶段,该区火山喷发的不同时期,水参与喷发的程度不同。 相似文献
19.
Tephrochronological study in the quaternary Val d’Agri intermontane basin (Southern Apennines,Italy)
Irene Zembo Pietro Vignola Sergio Andò Riccardo Bersezio Luigina Vezzoli 《International Journal of Earth Sciences》2011,100(1):173-187
In the south-eastern depocentre of the Val d’Agri basin (Southern Apennines), a volcanic ash layer crops out interbedded within
poorly structured alluvial fan deposits of Late Pleistocene age. Textural, depositional and pedological features of this weathered
layer suggest a primary deposition from a pyroclastic fall-out of volcanic ash. Chemical analyses of feldspars show an alkali
trachytic composition and accessory minerals association allow to correlate this tephra layer with the regionally dispersed
Y-7 marine tephra layer (Tufo Verde Epomeo eruption, Ischia volcano), dated at 56 ± 4 ka. The Val d’Agri tephra here described
for the first time was deposited during MIS Stage 3. Its recovery and characterization permit to contribute to regional correlation
of the Mediterranean climatic and volcanic events from marine to continental successions and to describe landscape evolution
of the Southern Apennines during glacial–interglacial cycles. 相似文献
20.
Martina M. Halmer 《地学学报》2005,17(6):500-502
Earth's ozone layer is only a very small part of the atmosphere, but its intact abundance is most important to the vitality of human beings. Observations have shown that especially after the plinian eruption of Pinatubo volcano in 1991 the ozone layer showed a dramatic depletion. Could a similar hypothetic eruption in the future cause an equal effective destruction of ozone while considering the increasing reduction of man-made halogens in the stratosphere after the Montreal protocol in 1987? 相似文献