Virtual tools for volcanic crisis management, and evacuation decision support: applications to El Chichón volcano (Chiapas, México)

Decision making regarding massive evacuation of a population threatened by a probable volcanic eruption is a major problem in crisis management. Such a decision is general on the number of people to be evacuated, available resources and infrastructure, quantity and quality of the escape routes and shelters, and the economic, social and political costs involved in the operation, coupled with the updated information provided by scientists about the forecast of future activity and probable eruption scenarios. Knowing time-lapse between the evacuation decision-making time and the time in which the evacuation is completed is another critical issue that must be carefully considered in densely populated areas. In such areas, it is really important to estimate in advance this time-lapse, as the forecast must be released with enough time to complete all the evacuation process before the destructive manifestations of the eruption begin. In this context, evacuation planning is a crucial component of emergency management. It is common for Emergency Plans to include pre-established strategies. However, an evacuation procedure should be flexible, depending on the above-mentioned timing, and on the decisions, evacuation schemes, environmental characteristics and other factors. In this work, several hazard models such as a lava flow model based on a Monte Carlo algorithm, a pyroclastic density current based on energy cone model, a semi-empirical inversion model to estimate the thickness of ash deposits, and all available information about the El Chión volcano have been used to obtain the area that should be evacuated in case of an eruption. Then, multiple evacuation strategies at El Chichón volcano have been designed, considering not only the characteristics of the eruption forecast, but also environmental factors (e.g., weather conditions) and social factors (e.g., tourism and farming seasons). The variable scale evacuation model has been used to estimate the evacuation time. In the paper, those virtual tools are briefly described as well as the information obtained from the drill of 2009. In addition to the optimization of evacuation under variable conditions and situations, one of the main objectives of this work is to provide a reliable estimation of the mitigation action time, for an Emergency Plan.     

Large-scale phenomena on the Sun associated with the eruption of filaments outside active regions: the event of September 12, 1999

The event of September 12, 1999 is used to analyze large-scale disturbances associated with coronal mass ejections during the eruption of filaments outside active regions. The analysis is based on Hα filtergrams, EUV and soft X-ray images, and coronograph data. The filament eruption occurred in relatively weak magnetic fields, but was accompanied by larger-scale phenomena than flare events. During several hours after the eruption, a large-scale arcade developed, whose bases formed diverging flare-like ribbons. The volume of the event was bounded by an “EIT wave”, which was quasi-stationary at the solar surface and expanded above the limb. The event did not have an impulsive component; therefore the “EIT wave” above the limb was a magnetic structure, identified as the front of a coronal mass ejection by virtue of its shape, structural features, and kinematics. Three types of dimmings were observed within the areal of the event, cause by (a) the evacuation of plasma, (b) heating of plasma with its subsequent evacuation, and (c) the absorption of radiation in a system of filaments activated by the eruption. The fact that a dimming appeared due to plasma heating was revealed by its presence in soft X-rays, whereas the four EIT channels did not demonstrate this. This brings into question the correctness of certain conclusions drawn earlier based purely on EIT data. A transformation of magnetic fields brought about by the eruption also occurred in a stationary coronal hole adjacent to the areal of the event. The expansion of the coronal mass ejection was self-similar and characterized by a rapidly decreasing acceleration, which is not taken into account in the widely used polynomial approximation.     

Precursors to the plinian eruptions of thera (late bronze age) and vesuvius (AD 79): Data from archaeological areas

Volcanological studies in the Bronze Age settlement of Akrotiri (Santorini, Greece) and in the Roman towns of Pompeii and Herculaneum (Vesuvius, Italy) provided information about the precursory phenomena preceding the Minoan and AD 79 plinian eruptions. Both the eruptions were characterised by seismic precursors with very different magnitudes and effects. The Minoan eruption was preceded by strong earthquake(s) that destroyed the Akrotiri settlement and forced an early evacuation of the island before the onset of the eruption. Instead, only some low magnitude shakings occurred before the AD 79 eruption of Vesuvius, which caught Roman towns and their inhabitants in the middle of their every-day life. Clear evidences of real volcanic precursors (both magmatic and phreatic) are not recorded in the deposits of the two eruptions. The onset of volcanic activity in both cases was represented by phreatomagmatic pulses of low energy shortly followed by the main eruption.     

Main issues of an evacuation in case of volcanic crisis: social stakes in Guadeloupe (Lesser Antilles Arc)

The last major eruption of La Soufrière volcano in Guadeloupe (Lesser Antilles) in 1976–1977 caused the mass evacuation of part of the population, whereby a total of 76,000 people were displaced for a period of 3–6 months. This evacuation has left a bitter memory among the inhabitants who believed that the political authorities of the time had not anticipated the possibility of an eruption crisis and that decisions were taken in haste. La Soufrière remains active, and future eruptions could once again lead to partial or even total evacuation of the population if there were a major Plinian eruption. This article offers an investigation of future evacuation procedures, questioning different aspects of Guadeloupe’s current territorial and social challenges (the multi-risk context, the reporting to the scientists and to the authorities, the importance of local solidarity). In order to do so, we used the Focus Group Discussion method, making it possible to identify resources and gaps in crisis management on the basis of previous event history.     

When the gods are angry: volcanic crisis and eruption at Bali's great volcano

In November 2017, Bali's ‘great volcano’, Gunung Agung, erupted for the first time since 1963—leading to the evacuation of nearly 150 000 people from a preliminary danger zone within a radius of 9–12 km from the summit. Since the phreatic onset of the eruption on 21 November, intermittent magmatic (Vulcanian) explosions continued to threaten local residents and disrupt air traffic to and from Indonesia's favourite tourist destination. Whereas the opening of the eruption seems to have been less energetic than the opening of the 1963 events, as of January 2018, the volcanic Alert Level for Agung remains at the highest level. Indeed, it remains unclear at this point what course the eruption will take and how long it will last, and the possibility remains that the eruption may turn more energetic in the months to come.     

矿物热电效应与火山地震之热电异常

地壳物质组成的不均一性及矿物形成物理化学条件的复杂性决定了地壳内广泛存在半导体矿物。半导体矿物的主要特征之一是晶格内存在一定量由成分(本征元素或杂质元素)异化或结构缺陷形成的潜在载流子。当遇有温差热激发条件时,梯度温度场会驱动矿物晶体内的潜在载流子定向移动,进而产生温差热电势,这种现象称作热电效应。一般来说,火山地震孕育和发生过程中其震源处常常存在由扰动热流而产生的不均匀热场,该热场的梯度效应(温差效应)能够触发半导体矿物产生热电效应,并将热能转化成电能。因此推测,作为火山地震的重要前兆之一,地电异常的出现很可能存在热电效应的贡献,即火山地震地电异常存在热电效应机制。这一认识对于深刻理解火山地震孕育过程中的地电异常具有启示意义。     

大理—剑川地区新生儿火山岩岩石学特征及火山喷发期研究

大理－剑川地区分布一套新生代火山岩，称剑川组。以洱海断裂带为界，东侧主要为基性，超基性岩，西侧主要为粗面岩。据火山岩系沉积特征及所含植物化石判断，喷发期为中新世，原划分的双河组，剑川组应是同期产物。     

Simulation-based optimization of emergency evacuation strategy in ultra-high-rise buildings

Emergency evacuation in high-rise buildings is a crucial problem. The evacuation strategy of using stairs and evacuation elevators should be optimized. In this paper, simulation-based optimization method is used to optimize the evacuation strategy of using stairs and elevators in high-rise buildings. The stair simulation is based on a cellular automata model, and several typical pedestrians’ walk preferences are considered in this model. In the simulation, evacuation elevators can arrive at the refuge floors, and the scheduling of the elevators is optimized based on the GA algorithm. The simulation-based optimization is designed as a two-level problem: The upper level is a strategy level; the lower level is an operation level. In the study case, the evacuation strategy of a 100-floor ultra-high-rise office building is optimized. We find that if evacuees follow the traditional stair evacuation strategy, the evacuation time is 42.6 min. After optimization, the evacuation time of optimal strategy by using both stairs and elevators is 25.1 min. Compared with the traditional stair evacuation strategy, the efficiency of evacuation is improved by 41.1%. It is also found that the merging behavior in stairwells will decrease the velocity of the pedestrian flow. Stairs are still the main egress, and evacuation elevators are an assistant egress during high-rise building evacuation.     

Applying neighbourhood classification systems to natural hazards: a case study of Mt Vesuvius

Mt Vesuvius is regarded as one of the most deadly volcanoes on earth. With over 1 million people living on its flanks and in its periphery, there is little doubt that an eruption of sub-Plinian magnitude would be catastrophic to the livelihood and well being of contemporary Neopolitans. Such a large scale eruption would have wide ranging and differential effects on the surrounding population. Whereas previous studies of social vulnerability have focused on individual demographic factors (such as age, income or ethnicity), this research proposes the application of a general neighbourhood classification system to assess natural hazard vulnerability. In this study, Experian’s Mosaic Italy is used to classify and delineate the most vulnerable neighbourhood types around the province of Naples. Among the neighbourhoods considered most at risk, those areas with high proportions of elderly and low income families are deemed particularly vulnerable. With current evacuation plans deemed outdated and poorly communicated to the locals Rolandi (2010), Barberi et al. (2008), this methodology could prove to be a useful input to both town planners and civil protection agencies. A range of statistical measures and geophysical risk boundaries are employed here to assess the different areas of human resilience.     

Oceans of magma: Large Igneous Provinces (LIPS) and plumes

The Mt St Helens eruption of 1989 created world news and called forth expressions from journalists such as ‘the unbelievable power of Nature’ and ‘incredible powers of destruction’. Yet, this eruption pales into insignificance in the light of earlier volcanic events. Mt St Helens is estimated to have produced 1.2 cubic kilometres of solid material. Laki, in Iceland, is the most voluminous eruption in historic times and is estimated to have produced around 14 cubic kilometres of lava in 1783 to 1784. However, geologists know of older single eruptions that produced hundreds or even thousands of cubic kilometers of solid material and here I tell of a volcanic event that resulted in between one and ten million cubic kilometres of material in just a couple of million years or so. If this occurred at the present day it would almost certainly wipe out mankind and, indeed, earlier mass extinction events are ascribed to similar phenomena which have happened several times in the past. These events created ‘Large Igneous Provinces’ (LIPs) and here I concentrate on part of one of these to give an impression of their nature, examining what might be the cause of such enormous amounts of magma.     

Heterogeneity, Correlatives, and Proposed Stratigraphic Nomenclature of Hayes Tephra Set H, Alaska

Several Holocene tephra deposits of Hayes volcano constitute a marker horizon in southern and east-central Alaska. Their identification is aided by high amphibole/pyroxene ratio and biotite in trace amounts, unique among Holocene tephra deposits of the region. However, correlations are obscured by chemical heterogeneity of the glass which occurs at a scale less than the size of a lapilli. Single-shard analyses confirm that the heterogeneity is due neither to fractionation nor to plagioclase microlites. The heterogeneity may be due to mixing of magmas prior to eruption. It is proposed that the deposits be informally called Hayes tephra set H.     

Multiple timescale constraints for high-flux magma chamber assembly prior to the Late Bronze Age eruption of Santorini (Greece)

The rhyodacitic magma discharged during the 30–80 km³ DRE (dense rock equivalent) Late Bronze Age (LBA; also called ‘Minoan’) eruption of Santorini caldera is known from previous studies to have had a complex history of polybaric ascent and storage prior to eruption. We refine the timescales of these processes by modelling Mg–Fe diffusion profiles in orthopyroxene and clinopyroxene crystals. The data are integrated with previously published information on the LBA eruption (phase equilibria studies, melt inclusion volatile barometry, Mg-in-plagioclase diffusion chronometry), as well as new plagioclase crystal size distributions and the established pre-LBA history of the volcano, to reconstruct the events that led up to the assembly and discharge of the LBA magma chamber. Orthopyroxene, clinopyroxene and plagioclase crystals in the rhyodacite have compositionally distinct rims, overgrowing relict, probably source-derived, more magnesian (or calcic) cores, and record one or more crystallization (plag???opx?>?cpx) events during the few centuries to years prior to eruption. The crystallization event(s) can be explained by the rapid transfer of rhyodacitic melt from a dioritic/gabbroic region of the subcaldera pluton (mostly in the 8–12 km depth range), followed by injection, cooling and mixing in a large melt lens at 4–6 km depth (the pre-eruptive magma chamber). Since crystals from all eruptive phases yield similar timescales, the melt transfer event(s), the last of which took place less than 2 years before the eruption, must have involved most of the magma that subsequently erupted. The data are consistent with a model in which prolonged generation, storage and segregation of silicic melts were followed by gravitational instability in the subcaldera pluton, causing the rapid interconnection and amalgamation of melt-rich domains. The melts then drained to the top of the pluton, at fluxes of up to 0.1–1 km³ year^??1, where steep vertical gradients of density and rheology probably caused them to inject laterally, forming a short-lived holding chamber prior to eruption. This interpretation is consistent with growing evidence that some large silicic magma chambers are transient features on geological timescales. A similar process preceded at least one earlier caldera-forming eruption on Santorini, suggesting that it may be a general feature of this rift-hosted magmatic system.     

内蒙古达里诺尔晚新生代火山群喷发特征研究

达里诺尔火山群有近百座晚新生代单成因火山,其地质地貌形态各异,喷发形式多样。这些火山既有爆破式喷发,如:夏威夷式喷发,斯通博利式喷发,强斯通博利式喷发和射汽岩浆喷发;也有溢流式喷发,如盾状火山;还有岩浆缓慢侵出,如大黑山。火山群内典型火山机构表明,不同的喷发方式穿插于火山喷发过程:早期火山活动多以侵出和溢流为主,逐渐转变为岩浆爆破式喷发(强斯通博利式,斯通博利式),晚期又过渡为溢流式喷发,喷发过程大体经历一个爆破强度弱-强-弱的转变。射汽岩浆型的火山则是以剧烈的射汽岩浆爆炸开始,后期逐渐转弱为岩浆爆破喷发和溢流喷发。火山喷发过程中火山产物出现牛顿流体,宾汉流体,层流,颗粒流,涌流,空降等不同类型的运动形式,自火口向远源运动,形成差异化的火山产物。岩浆的输送速率、上升速度,以及围岩的类型,可能是造成达里诺尔火山群多样化喷发的主要因素。     

The genesis of pyroclasts and the mechanism of submarine eruption of Naozhou Island in Guangdong,South ChinaSCIEI北大核心CSCD

水下火山喷发作用机制不同于陆地环境喷发,随着水参与程度的变化,喷发机制趋向复杂。本文以雷琼火山群的湛江硇洲岛作为研究对象,聚焦浅海火山产物的判断依据和水下火山喷发机制。硇洲岛是我国最大的第四纪火山岛,其上的那晏湾剖面保留了完整的火山喷发堆积序列。在那晏湾剖面的凝灰岩中,主要有三类火山成因的大粒径原生碎屑(2-5mm):塑变熔岩碎屑、碎玄玻璃及玄武玻璃,推断为不同程度水-岩浆相互作用的产物,根据水的参与程度大致排序为:碎玄玻璃>玄武玻璃>塑变熔岩碎屑。通过对硇洲岛水-火山作用机制研究,发现水-岩浆混合质量比(Mwater/Mmelt)是控制爆炸强度和火山碎屑粒度的关键因素。火山喷发序列分析表明,硇洲岛的喷发过程总体可分为三期,早期是冰岛苏特塞式喷发的浅水环境蒸汽爆炸与“火喷泉”喷发;中期过渡转为“火喷泉”喷发,伴随陆上的射汽岩浆喷发;最终以岩浆溢流式喷发结束。     

The logistics of household hurricane evacuation

Although there is a substantial amount of research on households’ hurricane evacuation decision making, there is much less research on the logistical issues involved in implementing those evacuations. The limited research on household evacuation logistics has consistently shown that most evacuees stay in the homes of friends and relatives or in commercial facilities rather than in public shelters. However, evacuation logistics—which can be defined as the activities and associated resources needed to reach a safe location and remain there until it is safe to return—encompasses a much broader range of behaviors than this. The present study extends previous research by reporting data on other aspects of evacuation logistics such as departure timing, vehicle use, evacuation routes, travel distance, shelter type, evacuation duration, and evacuation cost. Hurricane Lili evacuation data at the county level are generally consistent with the data from previous hurricanes, but there is notable variation across counties studied here. There were only modest correlations of demographic and geographic variables with the evacuation logistics variables, a result that indicates further research is needed to better understand what happens between the time an evacuation decision is made and the time re-entry is begun. Moreover, research is needed to understand the logistics of evacuation by special populations such as transients and households with disabled members.     

新疆伊宁盆地尼勒克地区二叠纪地层研究新进展

尼勒克地区二叠纪地层分布面积最广，地层出露齐全，接触关系清楚，包括5个组的全部层型剖面在内，是在西天山研究二叠纪地层的经典地区．通过对5条层型剖面全部进行重测，系统采集样品，取得了成果．主要体现在火山喷发旋回研究、生物化石及岩相分析研究，并进行较详细的地层划分，为西天山二叠纪地层划分与对比提供了可靠依据．     

Computer-based Model for Flood Evacuation Emergency Planning

A computerized simulation model for capturing human behavior during flood emergency evacuation is developed using a system dynamics approach. It simulates the acceptance of evacuation orders by the residents of the area under threat; number of families in the process of evacuation; and time required for all evacuees to reach safety. The model is conceptualized around the flooding conditions (physical and management) and the main set of social and mental factors that determine human behavior before and during the flood evacuation. The number of families under the flood threat, population in the process of evacuation, inundation of refuge routes, flood conditions (precipitation, river elevation, etc.), and different flood warnings and evacuation orders related variables are among the large set of variables included in the model. They are linked to the concern that leads to the danger recognition, which triggers evacuation decisions that determine the number of people being evacuated. The main purpose of the model is to assess the effectiveness of different flood emergency management procedures. Each procedure consists of the choice of flood warning method, warning consistency, timing of evacuation order, coherence of the community, upstream flooding conditions, and set of weights assigned to different warning distribution methods. Model use and effectiveness are tested through the evaluation of the effectiveness of different flood evacuation emergency options in the Red River Basin, Canada.     

五大连池老黑山、火烧山的火山喷发特征

从野外调查及火山喷发观测记录入手, 结合国内外火山研究的新进展, 在火山成因类型、喷发方式及喷发前兆等方面讨论了五大连池老黑山、火烧山的火山喷发特征。指出老黑山、火烧山的火山成因类型属于单成因火山, 喷发方式不是简单的中心式喷发, 而是经历了裂隙式喷发后转为中心式喷发。通过火山喷发观测记录的分析及与国外火山对比, 揭示出此次火山喷发是有前兆的, 其前兆特征对监测预报未来火山喷发有借鉴意义。     

A novel agent-based model for tsunami evacuation simulation and risk assessment

Tsunami evacuation is an effective way to save lives from the near-field tsunami. Realistic evacuation simulation can provide valuable information for accurate evacuation risk assessment and effective evacuation planning. Agent-based modeling is ideal for tsunami evacuation simulation due to its capability of capturing the emergent phenomena and modeling the individual-level interactions among agents and the agents’ interactions with the environment. However, existing models usually neglect or simplify some important factors and/or mechanisms in tsunami evacuation. For example, uncertainties in seismic damages to the transportation network are not probabilistically considered (e.g., by simply removing the damaged links (roads/bridges) from the network). Typically a relatively small population (i.e., evacuees) is considered (due to computational challenges) while neglecting population mobility. These simplifications may lead to inaccurate estimation of evacuation risk. Usually, only single traffic mode (e.g., on foot or by car) is considered, while pedestrian speed adjustment and multi-modal evacuation (e.g., on foot and by car) are not considered concurrently. Also, pedestrian–vehicle interaction is usually neglected in the multi-modal evacuation. To address the above limitations, this study proposes a novel and more realistic agent-based tsunami evacuation model for tsunami evacuation simulation and risk assessment. Uncertainties in seismic damages to all links in the transportation network as well as uncertainties in other evacuation parameters are explicitly modeled and considered. A novel and more realistic multi-modal evacuation model is proposed that explicitly considers the pedestrian–vehicle interaction, walking speed variability, and speed adjustment for both the pedestrian and car according to traffic density. In addition, several different population sizes are used to model population mobility and its impact on tsunami evacuation risk. The proposed model is applied within a simulation-based framework to assess the tsunami evacuation risk assessment for Seaside, Oregon.

     

冰岛卡特拉火山未来喷发特征的判定

卡特拉火山近期活动频繁,其喷发概率、喷发规模、喷发方式及影响都备受瞩目.通过收集整理若干资料和分析计算,采用“将古论今”的研究方法,初步得到了关于卡特拉火山未来可能的行为方式及影响.根据卡特拉火山喷发的历史规律,估算2013年的喷发概率约为30%.卡特拉火山下次喷发规模可能为4级或5级,其喷发方式有3种:其一是岩浆冲破巨厚冰层发生爆破性喷发;其二是正常的岩浆喷发;其三是夭折的喷发.但根据现有资料分析,卡特拉火山最有可能是以见不到喷发的形式结束这次不稳定性活动.