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1.
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2.
On 29–30 November 2006, heavy rains from Supertyphoon Durian remobilized volcanic debris on the southern and eastern slopes of Mount Mayon, generating major lahars that caused severe loss of life and property in downstream communities. The nearby Legaspi City weather station recorded 495.8 mm of rainfall over 1.5 days at rates as high as 47.5 mm/h, far exceeding the initiation threshold for Mayon lahars. For about 18 h, floods and lahars from the intense and prolonged rainfall overtopped river bends, breaching six dikes through which they created new paths, buried downstream communities in thick, widespread deposits, and caused most of the 1,266 fatalities. In order to mitigate damage from future lahars, the deposits were described and analyzed for clues to their generation and impact on structures and people. Post-disaster maps were generated from raw ASTER and SPOT images, using automated density slicing to characterize lahar deposits, flooded areas, croplands, and urbanized areas. Fieldwork was undertaken to check the accuracy of the maps, especially at the edges of the lahar deposits, and to measure the deposit thicknesses. The Durian event was exceptional in terms of rainfall intensity, but the dikes eventually failed because they were designed and built according to flood specifications, not to withstand major lahars.  相似文献   

3.
Nevado del Huila, a glacier-covered volcano in the South of Colombia’s Cordillera Central, had not experienced any historical eruptions before 2007. In 2007 and 2008, the volcano erupted with phreatic and phreatomagmatic events which produced lahars with flow volumes of up to about 300 million m3 causing severe damage to infrastructure and loss of lives. The magnitude of these lahars and the prevailing potential for similar or even larger events, poses significant hazards to local people and makes appropriate modeling a real challenge. In this study, we analyze the recent lahars to better understand the main processes and then model possible scenarios for future events. We used lahar inundation depths, travel duration, and flow deposits to constrain the dimensions of the 2007 event and applied LAHARZ and FLO-2D for lahar modeling. Measured hydrographs, geophone seismic sensor data and calculated peak discharges served as input data for the reconstruction of flow hydrographs and for calibration of the models. For model validation, results were compared with field data collected along the Páez and Simbola Rivers. Based on the results of the 2007 lahar simulation, we modeled lahar scenarios with volumes between 300 million and 1 billion m3. The approach presented here represents a feasible solution for modeling high-magnitude flows like lahars and allows an assessment of potential future events and related consequences for population centers downstream of Nevado del Huila.  相似文献   

4.
Lahars (volcanic debris flows) have been responsible for 40% of all volcanic fatalities over the past century. Mount Semeru (East Java, Indonesia) is a persistently active composite volcano that threatens approximately one million people with its lahars and pyroclastic flows. Despite their regularity, the behaviour and the propagation of these rain‐triggered lahars are poorly understood. In situ samples were taken from lahars in motion at two sites in the Curah Lengkong River, on the southeast flank of Semeru, providing estimates of the particle concentration, grain size spectrum, grain density and composition. This enables us to identify flow sediment from three categories of lahars: (a) hyperconcentrated flow, (b) non‐cohesive, clast‐ and matrix‐supported debris flow, and (c) muddy flood. To understand hyperconcentrated flow sediment transport processes, it is more appropriate to sample the active flows than the post‐event lahar deposits because in situ sampling retains the full spectrum of the grain‐size distribution. Rheometrical tests on materials sampled from moving hyperconcentrated flows were carried out using a laboratory vane rheometer. Despite technical difficulties, results obtained on the <63, <180, and <400 µm fractions of the sampled sediment, suggest a purely frictional behaviour. Importantly, and contrary to previous experiments conducted with monodisperse suspensions, our results do not show any transition towards a viscous behaviour for high shear rates. These data provide important constraints for future physical and numerical modelling of lahar flows. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

5.
Mt. Ruapehu, in the central North Island of New Zealand, is one of the most lahar-prone volcanoes in the world. Since historic observations began in 1861 AD, more than 50 individual lahars have been recorded in the Whangaehu valley alone, the natural outlet to the summit Crater Lake. These lahars have been triggered by a variety of mechanisms, including explosive eruptions that displaced Crater Lake water over the outlet or ejected it onto the snow-clad summit area of the volcano; rain-remobilisation of tephra deposits on steep slopes; displacement over the outlet as a result of syn-eruptive changes in lake bathymetry; and lake break-outs from Crater Lake following impoundment of excess water behind temporary barriers of tephra and/or ice emplaced over the outlet. However, only 9 lahar deposits can be distinguished in the upper Whangaehu valley on sedimentological, stratigraphic, geomorphic and petrological grounds, and these are skewed towards either the largest or the most recent flows. In some cases magnitude can be reconstructed from deposit geometry, with the largest lahars producing the highest level terraces, the coarsest deposits, and crossing drainage divides into normally inactive channels. This under-representation of historic events reflects the low preservation potential of unconsolidated deposits in a steep alpine environment, and the overprinting and recycling effect of large magnitude lahars that rework material down to bedrock and effectively reset the stratigraphic record. Development of magnitude-frequency relationships for Ruapehu lahars therefore requires the identification of lahar deposits in proximal, medial and distal settings in order to ensure that the full range of events is represented.  相似文献   

6.
Ruapehu is a very active andesitic composite volcano which has erupted five times in the past 10 years. Historical events have included phreatomagmatic eruptions through a hot crater lake and two dome-building episodes. Ski-field facilities, road and rail bridges, alpine huts and portions of a major hydroelectrical power scheme have been damaged or destroyed by these eruptions. Destruction of a rail bridge by a lahar in 1953 caused the loss of 151 lives. Other potential hazards, with Holocene analogues, include Strombolian and sub-Plinian explosive eruptions, lava extrusion from summit or flank vents and collapse of portions of the volcano. The greatest hazards would result from renewed phreatomagmatic activity in Crater Lake or collapse of its weak southeastern wall. Three types of hazard zones can be defined for the phreatomagmatic events: inner zones of extreme risk from ballistic blocks and surges, outer zones of disruption to services from fall deposits and zones of risk from lahars, which consist of tongues down major river valleys. Ruapehu is prone to destructive lahars because of the presence of 107 m3 of hot acid water in Crater Lake and because of the surrounding summit glaciers and ice fields. The greatest risks at Ruapehu are to thousands of skiers on the ski field which crosses a northern lahar path. Three early warning schemes have been established to deal with the lahar problems. Collapse of the southeastern confining wall would release much of the lake into an eastern lahar path causing widespread damage. This is a long-term risk which could only be mitigated by drainage of the lake.  相似文献   

7.
Field, geochronologic, and geochemical evidence from proximal fine-grained tephras, and from limited exposures of Holocene lava flows and a small pyroclastic flow document ten–12 eruptions of Mount Rainier over the last 2,600 years, contrasting with previously published evidence for only 11–12 eruptions of the volcano for all of the Holocene. Except for the pumiceous subplinian C event of 2,200 cal year BP, the late-Holocene eruptions were weakly explosive, involving lava effusions and at least two block-and-ash pyroclastic flows. Eruptions were clustered from ∼2,600 to ∼2,200 cal year BP, an interval referred to as the Summerland eruptive period that includes the youngest lava effusion from the volcano. Thin, fine-grained tephras are the only known primary volcanic products from eruptions near 1,500 and 1,000 cal year BP, but these and earlier eruptions were penecontemporaneous with far-traveled lahars, probably created from newly erupted materials melting snow and glacial ice. The most recent magmatic eruption of Mount Rainier, documented geochemically, was the 1,000 cal year BP event. Products from a proposed eruption of Mount Rainier between AD 1820 and 1854 (X tephra of Mullineaux (US Geol Surv Bull 1326:1–83, 1974)) are redeposited C tephra, probably transported onto young moraines by snow avalanches, and do not record a nineteenth century eruption. We found no conclusive evidence for an eruption associated with the clay-rich Electron Mudflow of ∼500 cal year BP, and though rare, non-eruptive collapse of unstable edifice flanks remains as a potential hazard from Mount Rainier. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. T. W. Sisson and J. W. Vallance contributed equally to this study.  相似文献   

8.
Lahars are among the most hazardous mass flow processes on earth and have caused up to 23 000 casualties in single events in the recent past. The Cotopaxi volcano, 60 km southeast of Quito, has a well-documented history of massively destructive lahars and is a hotspot for future lahars due to (i) its ~10 km2 glacier cap, (ii) its 117–147-year return period of (Sub)-Plinian eruptions, and (iii) the densely populated potential inundation zones (300 000 inhabitants). Previous mechanical lahar models often do not (i) capture the steep initial lahar trajectory, (ii) reproduce multiple flow paths including bifurcation and confluence, and (iii) generate appropriate key parameters like flow speed and pressure at the base as a measure of erosion capacity. Here, we back-calculate the well-documented 1877 lahar using the RAMMS debris flow model with an implemented entrainment algorithm, covering the entire lahar path from the volcano edifice to an extent of ~70 km from the source. To evaluate the sensitivity and to constrain the model input range, we systematically explore input parameter values, especially the Voellmy–Salm friction coefficients μ and ξ. Objective selection of the most likely parameter combinations enables a realistic and robust lahar hazard representation. Detailed historic records for flow height, flow velocity, peak discharge, travel time and inundation limits match best with a very low Coulomb-type friction μ (0.0025–0.005) and a high turbulent friction ξ (1000–1400 m/s2). Finally, we apply the calibrated model to future eruption scenarios (Volcanic Explosivity Index = 2–3, 3–4, >4) at Cotopaxi and accordingly scaled lahars. For the first time, we anticipate a potential volume growth of 50–400% due to lahar erosivity on steep volcano flanks. Here we develop a generic Voellmy–Salm approach across different scales of high-magnitude lahars and show how it can be used to anticipate future syneruptive lahars.  相似文献   

9.
Merapi volcano, in Central Java, is one of the most active volcanoes in the world. At least 23 of the 61 reported eruptions since the mid-1500s have produced source deposits for lahars. The combined lahar deposits cover about 286 km2 on the flanks and the surrounding piedmonts of the volcano. At Merapi, lahars are commonly rain-triggered by rainfalls having an average intensity of about 40 mm in 2 h. Most occur during the rainy season from November to April, and have average velocities of 5–7 m/s at 1000 m in elevation. A wide range of facies may be generated from a single flow, which may transform downvalley from debris flow to hyperconcentrated streamflow.Because of the high frequency and magnitude of the lahar events, lahar-related hazards are high below about 450–600 m elevation in each of the 13 rivers which drain the volcano. Hazard-zone maps for lahar were produced by Pardyanto et al. (Volcanic hazard map, Merapi volcano, Central Java (1/100,000). Geol. Surv. of Indonesia, Bandung, II, 4, 1978) and the Japanese–Indonesian Cooperation Agency (Master plan for land conservation and volcanic debris control in the area of Mt Merapi, Jakarta, 1980), but these maps are of a very small scale to meet modern zoning requirements. More recently, a few large-scale maps (1/10,000- and 1/2000-scale) and risk assessments have been completed for a few critical river systems.  相似文献   

10.
Many research tools for lahar hazard assessment have proved wholly unsuitable for practical application to an active volcanic system where field measurements are challenging to obtain. Two simple routing models, with minimal data demands and implemented in a geographical information system (GIS), were applied to dilute lahars originating from Soufrière Hills Volcano, Montserrat. Single-direction flow routing by path of steepest descent, commonly used for simulating normal stream-flow, was tested against LAHARZ, an established lahar model calibrated for debris flows, for ability to replicate the main flow routes. Comparing the ways in which these models capture observed changes, and how the different modelled paths deviate can also provide an indication of where dilute lahars, do not follow behaviour expected from single-phase flow models. Data were collected over two field seasons and provide (1) an overview of gross morphological change after one rainy season, (2) details of dominant channels at the time of measurement, and (3) order of magnitude estimates of individual flow volumes. Modelling results suggested both GIS-based predictive tools had associated benefits. Dominant flow routes observed in the field were generally well-predicted using the hydrological approach with a consideration of elevation error, while LAHARZ was comparatively more successful at mapping lahar dispersion and was better suited to long-term hazard assessment. This research suggests that end-member models can have utility for first-order dilute lahar hazard mapping.  相似文献   

11.
Lahars are water-sediment mass flows from a volcanic source. They can be triggered by a variety of mechanisms and span a continuum of flow rheology and hydraulic properties, even within the same event. Lahars are extremely powerful landscaping agents and represent a considerable hazard potential. However, this highly dynamic character and a lack of direct measurements has made modelling lahars difficult. This study therefore applies a fluid dynamics model; Delft3D, to analyse the 18th March 2007 dam break lahar at Mount Ruapehu, New Zealand. The modelled lahar routed through the Whangaehu gorge in ~30 min, crossed the Whangaehu fan in ~60 min, and then over a further 3 h travelled an additional ~22 km distance along the Whangaehu River to the Tangiwai bridge. The modelled mean frontal velocity was 6.5 m s−1 along the gorge although peak velocity reached up to 19.6 m s−1. The modelled lahar flow front progressively slowed across the fan but along the River it accelerated from 2.1–3.3 m s−1. Calculated peak velocity along the River was <4.5 m s−1. These results generally compare well with gauged records, with historical records, and with other modelling approaches. However, discrepancies in frontal velocity and time to peak stage arise due to (1) specifying roughness, which arises from slope variations between adjacent computational nodes, and which is stage-dependant, and (2) due to rapid topographic changes that produce frequent hydraulic jumps, which are inadequately accommodated in the numerical scheme. The overall pattern of discharge attenuation, and of relationships between topographic and hydraulic variables, is similar to that calculated for lahars on other volcanoes. This modelling method could be applied at other similar sites where a likely source hydrograph and high-resolution topographic data are available. These results have important implications for hazard management at Ruapehu and for examining geomorphic and sedimentary impacts of this lahar.  相似文献   

12.
A catastrophic lahar began on 30 October 1998, as hurricane precipitation triggered a small ?ank collapse of Casita volcano, a complex and probably dormant stratovolcano. The initial rockslide‐debris avalanche evolved on the ?ank to yield a watery debris ?ood with a sediment concentration less than 60 per cent by volume at the base of the volcano. Within 2·5 km, however, the watery ?ow entrained (bulked) enough sediment to transform entirely to a debris ?ow. The debris ?ow, 6 km downstream and 1·2 km wide and 3 to 6 m deep, killed 2500 people, nearly the entire populations of the communities of El Porvenir and Rolando Rodriguez. These ‘new towns’ were developed in a prehistoric lahar pathway: at least three ?ows of similar size since 8330 14C years bp are documented by stratigraphy in the same 30‐degree sector. Travel time between perception of the ?ow and destruction of the towns was only 2·5–3·0 minutes. The evolution of the ?ow wave occurred with hydraulic continuity and without pause or any extraordinary addition of water. The precipitation trigger of the Casita lahar emphasizes the need, in volcano hazard assessments, for including the potential for non‐eruption‐related collapse lahars with the more predictable potential of their syneruption analogues. The ?ow behaviour emphasizes that volcano collapses can yield not only volcanic debris avalanches with restricted runouts, but also mobile lahars that enlarge by bulking as they ?ow. Volumes and hence inundation areas of collapse‐runout lahars can increase greatly beyond their sources: the volume of the Casita lahar bulked to at least 2·6 times the contributing volume of the ?ank collapse and 4·2 times that of the debris ?ood. At least 78 per cent of the debris ?ow matrix (sediment < ?1·0Φ; 2 mm) was entrained during ?ow. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

13.
The eruption of Mount Pinatubo in June 1991 altered the conditions of the surrounding river catchments. Pyroclastic flows and tephra fall were deposited over extensive areas, stripping off the forest cover and burying drainage divides. These recent deposits are very loosely consolidated and generally consist of sand‐sized particles, which commonly mobilize into lahars in response to rainfall of a certain magnitude. Several devastating lahar occurrences have buried settlements covering tens to several hundred square kilometres in a single event. Correlation of storm rainfall intensities and durations with lahar activity as recorded by acoustic flow monitors is used to investigate trends in the initiation conditions for lahar activity. This research confirms that the relationships of rainfall intensity and duration with lahar initiation threshold values are not linear but rather approximate a power relation. Different relations were found for lahar initiation in different years, from 1991 to 1997, as a result of the dynamic changes in hydrologic and geomorphic conditions of the affected catchments. Data from acoustic flow monitors are used to distinguish debris flow and hyperconcentrated flow activity from that of muddy water. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

14.
Of 1.1 million people living on the flanks of the active Merapi volcano, 440,000 are at relatively high risk in areas prone to pyroclastic flows, surges, and lahars. For the last two centuries, the activity of Merapi has alternated regularly between long periods of viscous lava dome extrusion, and brief explosive episodes at 8–15 year intervals, which generated dome-collapse pyroclastic flows and destroyed part of the pre-existing domes. Violent explosive episodes on an average recurrence of 26–54 years have generated pyroclastic flows, surges, tephra-falls, and subsequent lahars. The 61 reported eruptions since the mid-1500s killed about 7000 people. The current hazard-zone map of Merapi (Pardyanto et al., 1978) portrays three areas, termed ‘forbidden zone’, ‘first danger zone’ and ‘second danger zone’, based on successively declining hazards. Revision of the hazard map is desirable, because it lacks details necessary to outline hazard zones with accuracy, in particular the valleys likely to be swept by lahars, and excludes some areas likely to be devastated by pyroclastic gravity-currents such as the 22 November 1994 surge. In addition, risk maps should be developed to incorporate social, technical, and economic factors of vulnerability.Eruptive hazard assessment at Merapi is based on reconstructed eruptive history, on eruptive behavior and scenarios, and on existing models and preliminary numerical modeling. Firstly, the reconstructed eruptive activity, in particular for the past 7000 years and from historical accounts of eruptions, helps to define the extent and recurrence frequency of the most hazardous phenomena (Newhall et al., 2000; Camus et al., 2000). Pyroclastic flows traveled as far as 9–15 km from the source, pyroclastic surges swept the flanks as far as 9–20 km away from the vent, thick tephra fall buried temples in the vicinity of Yogyakarta 25 km to the south, and subsequent lahars spilled down the radial valleys as far as 30 km to the west and south. At least one large edifice collapse has occurred in the past 7000 years (Newhall et al., 2000; Camus et al., 2000). Secondly, four eruption scenarios are portrayed as hazardous zones on two maps and derived from the past eruptive behavior of Merapi and from the most affected areas in the past. Thirdly, simple numerical simulation, based on a Digital Elevation Model, a stereo-pair of SPOT satellite images, and one 2D-orthoimage helps to simulate pyroclastic and lahar flowage on the flanks and in radial valley channels, and to outline areas likely to be devastated.Three major threats are identified: (1) a collapse of the summit dome in the short-to mid-term, that can release large-volume pyroclastic flows and high-energy surges towards the south–southwest sector of the volcano; (2) an explosive eruption, much larger than any since 1930, may sweep all the flanks of Merapi at least once every century; (3) a potential collapse of the summit area, involving the fumarolic field of Gendol and part of the southern flank, which can contribute to moderate-scale debris avalanches and debris flows.  相似文献   

15.
 Akutan Volcano is one of the most active volcanoes in the Aleutian arc, but until recently little was known about its history and eruptive character. Following a brief but sustained period of intense seismic activity in March 1996, the Alaska Volcano Observatory began investigating the geology of the volcano and evaluating potential volcanic hazards that could affect residents of Akutan Island. During these studies new information was obtained about the Holocene eruptive history of the volcano on the basis of stratigraphic studies of volcaniclastic deposits and radiocarbon dating of associated buried soils and peat. A black, scoria-bearing, lapilli tephra, informally named the "Akutan tephra," is up to 2 m thick and is found over most of the island, primarily east of the volcano summit. Six radiocarbon ages on the humic fraction of soil A-horizons beneath the tephra indicate that the Akutan tephra was erupted approximately 1611 years B.P. At several locations the Akutan tephra is within a conformable stratigraphic sequence of pyroclastic-flow and lahar deposits that are all part of the same eruptive sequence. The thickness, widespread distribution, and conformable stratigraphic association with overlying pyroclastic-flow and lahar deposits indicate that the Akutan tephra likely records a major eruption of Akutan Volcano that may have formed the present summit caldera. Noncohesive lahar and pyroclastic-flow deposits that predate the Akutan tephra occur in the major valleys that head on the volcano and are evidence for six to eight earlier Holocene eruptions. These eruptions were strombolian to subplinian events that generated limited amounts of tephra and small pyroclastic flows that extended only a few kilometers from the vent. The pyroclastic flows melted snow and ice on the volcano flanks and formed lahars that traveled several kilometers down broad, formerly glaciated valleys, reaching the coast as thin, watery, hyperconcentrated flows or water floods. Slightly cohesive lahars in Hot Springs valley and Long valley could have formed from minor flank collapses of hydrothermally altered volcanic bedrock. These lahars may be unrelated to eruptive activity. Received: 31 August 1998 / Accepted: 30 January 1999  相似文献   

16.
A general model for Mt. Ruapehu lahars   总被引：1，自引：1，他引：1  
A mathematical model of the motion of lahars is presented. Lahar flows and travel speeds are calculated using a kinematic wave model which equates gravitational accelerations to frictional losses. A chezyor Manning-type law of friction is assumed, in which lahar flow rate is a simple power function of lahar depth, multiplied by another simple power of the chanel slope. Use of the model requires knowledge of essentially only one parameter which appears to be relatively insensitive for flows down a given channel. Variable channel slope effects are removed by a longitudinal scaling which applies to all flows down a given channel. For lahars generated by a single explosive event it is unnecessary to perform numerical calculations to predict lahar flow and travel time, but for lahnars produced by multiple sources in which different lahar flows are interacting, numerical calculations appear necessary. The model is applied to all recorded lahar flows from Mt. Ruapehu, and satisfactorily described all lahar flows generated by a single explosive mechanism. Such flows depend essentially only on total lahar volume. The 1968 Mt. Ruapehu lahar, generated by a series of smaller eruptive mechanisms, was modelled as the interaction of seven point sources of fluid originating from positions mathematically extrapolated up the mountain. Good agreement was obtained between the predicted times of formation of these 1968 lahars, and the times of greatest seismic amplitude.  相似文献   

17.
—Catastrophic edifice and sector failure occur commonly on stratovolcanoes worldwide and in some cases leave telltale horseshoe-shaped calderas. Many of these failures are now recognised as having resulted from large-scale landsliding. These slides often transform into debris avalanches and lahars that can devastate populations downstream of the volcano. Research on these phenomena has been directed mainly at understanding avalanche mechanics and travel distances and related socioeconomic impacts. Few investigations have examined volcanic avalanche source characteristics. The focus of this paper is to 1) describe a methodology for obtaining rock strengths that control initial failure and 2) report results of rock mass strength testing from Mount Rainier and Mount Hood. Rock mass and shear strength for fresh and hydrothermally altered rocks were obtained by 1) utilizing rock strength and structural information obtained from field studies and 2) applying rock mechanics techniques common in mining and civil engineering to the edifice region. Rock mass and intact rock strength differences greatly in excess of one order of magnitude were obtained when comparing strength behavior of fresh and completely altered volcanic rock. The recognition and determination of marked strength differences existing on the volcano edifice and flank, when combined with detailed geologic mapping, can be used to quantify volcano stability assessment and improve hazard mitigation efforts.  相似文献   

18.
This paper examines the relationship between volcanic risk and the tourism sector in southern Iceland and the complex challenge emergency management officials face in developing effective volcanic risk mitigation strategies. An early warning system and emergency response procedures were developed for communities surrounding Katla, the volcano underlying the Mýrdalsjökull ice cap. However, prior to and during the 2007 tourist season these mitigation efforts were not effectively communicated to stakeholders located in the tourist destination of Þórsmörk despite its location within the hazard zone of Katla. The hazard zone represents the potential extent of a catastrophic jökulhlaup (glacial outburst flood). Furthermore, volcanic risk mitigation efforts in Þórsmörk were based solely on information derived from physical investigations of volcanic hazards. They did not consider the human dimension of risk. In order to address this gap and provide support to current risk mitigation efforts, questionnaire surveys were used to investigate tourists' and tourism employees' hazard knowledge, risk perception, adoption of personal preparedness measures, predicted behaviour if faced with a Katla eruption and views on education.Results indicate that tourists lack hazard knowledge and they do not adopt preparedness measures to deal with the consequences of an eruption. Despite a high level of risk perception, tourism employees lack knowledge about the early warning system and emergency response procedures. Results show that tourists are positive about receiving information concerning Katla and its hazards and therefore, the reticence of tourism employees with respect to disseminating hazard information is unjustified.In order to improve the tourism sector's collective capacity to positively respond during a future eruption, recommendations are made to ensure adequate dissemination of hazard, risk and emergency response information. Most importantly education campaigns should focus on: (a) increasing tourists' knowledge of Katla, jökulhlaup and other volcanic hazards and (b) increasing tourist and employee awareness of the early warning and information system and appropriate behavioural response if a warning is issued. Further, tourism employees should be required to participate in emergency training and evacuation exercises annually. These efforts are timely given that Katla is expected to erupt in the near future and international tourism is an expanding industry in Þórsmörk.  相似文献   

19.
本文讨论了与我国大陆火山地区相关的主要火山灾害类型,即火山空降物、火山碎屑流、火山泥石流、火山熔岩穹与熔岩流的成灾机制和灾害效应,并回顾了国际上火山灾害区划的研究现状,在此基础上,提出了适合我国具体情况的具有概率含义的火山灾害区划图的编图思路。  相似文献   

20.
我国火山灾害的主要类型及火山灾害区划图编制现状探讨   总被引：5，自引：0，他引：5  
通过对《核电厂厂址选择中的地震问题》(HAF0101(1))有关条款的详细剖析,发震构造包括两个方面的含义:一是曾经是地震震源的地质构造;二是未来可能发生破坏性地震的地质构造。地震重演原则和构造类比原则是判定发震构造的两条基本依据,但在实际工作中构造类比原则的应用往往存在较大难度,对中强地震发震构造的判定尤其如此。文中提出:对中强地震构造带地貌差异性和第四纪地层分布特征的研究有可能提供识别发生中强地震地质构造的标志。  相似文献   

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