Tenerife Volcanic Risk Assessment By Volcanic Hazards And Social Vulnerability

Volcanic eruptions will pose a huge threat to the lives and property of residents in volcanic areas.Comprehensive volcanic risk assessment is very important for disaster reduction and prevention in volcanic areas.In this thesis,Tenerife,Spain,is taken as the research area.Two eruption scenarios are defined as the Sub-Plinian eruption(scenario 1)of the central composite volcano(composed of Las Ca?adas edifice and Teide-Pico Viejo stratovolcano)and Strombolian eruption in the northeast-southwest and southeast-northwest ridges(scenario 2).Volcanic risk information system(VORIS)is used to simulate volcanic hazards.Then,based on the VSD(Vulnerability Scoring Diagram)framework,19 indicators are selected to evaluate Tenerife’s social vulnerability.Finally,the thesis comprehensively evaluates potential evacuation population and economic losses of Tenerife in different scenarios and types of volcanic risks.The main achievements and conclusions are as follows:(1)Based on the study of the eruption history and geological background of Tenerife’s volcano,the volcanic hazards in two eruption scenarios are set and simulated.The lava flow and pyroclastic density current in scenario 1 are affected by terrain factor.The lava flow is mainly distributed in the northwest,north and central region,and the pyroclastic density current is mainly distributed in the north and central region.The volcanic ash is mainly affected by wind direction and wind speed,mostly distributed in the north and northeast.The distribution of lava flow in scenario 2 is affected by the two ridges,mostly in the northwest,northern and eastern parts,and volcanic ash is mainly distributed in the northwest and northern parts.Compared with the two scenarios,the impact of the lava flow in scenario 2 on the northern municipalities is less than that in scenario 1,but the lava flow in scenario 2 affects the eastern municipalities,which is mainly due to the location of vents.Compared with scenario 2,scenario 1 has a larger impact in the northeast,but a smaller impact in the east.The ash in scenario 1 mainly accumulated in the middle and north,while the ash in scenario 2mainly accumulated in the northwest.(2)Based on the VSD model,19 indicators are selected from three sub-target layers of exposure,sensitivity and capability.The weight of indicators is calculated by AHP and entropy method,and then the social vulnerability of Tenerife is calculated.32.26% of the municipalities had higher exposure,25.80% had higher sensitivity,Tenerife had lower capability,and only three municipalities had higher capability.The municipalities in the north,east and southeast of Tenerife have higher social vulnerability.Among the 31 municipalities,the social vulnerability of 10 municipalities is relatively high(32.26%),that of 11 municipalities is medium(35.48%),that of 10 municipalities is relatively low(32.26%),and that of Tenerife is evenly distributed.(3)Based on the volcanic hazard simulations and social vulnerability assessment,the volcanic risks of Tenerife in different scenarios are evaluated.Among the three volcanic risks in scenario 1,the extremely high and high pyroclastic density current risk areas are the smallest,the extremely high and high ash risk areas are the most widely distributed.In Tenerife,the building areas with extremely high and high ash risk account for 48.13%,the building areas with extremely high and high lava flow risk account for 29.44%,and the building areas with extremely high and high pyroclastic density current risk account for 23.80%.The extremely high and high lava flow risk in scenario 2 is mainly distributed in the two ridge areas,and the extremely high and high volcanic ash risk is mainly distributed in the northwest,north and east of Tenerife.Compared with scenario 1,the urban volcanic ash risk in the northeast of scenario 2 is lower.In scenario 2,the lava flow risk and volcanic ash risk of urban buildings are close,the building area with extremely high and high lava flow risk accounts for 27.45%,and the building area with extremely high and high volcanic ash risk accounts for 30.62%,which is slightly higher than the lava flow risk.(4)Based on the volcanic risk,the potential evacuation population and economic loss are estimated.The potential evacuation population caused by volcanic risk in scenario 1 is higher than that in scenario 2.In scenario 1,the potential evacuation population of volcanic ash risk is 487000,while in scenario 2,the potential evacuation population is 265000.The potential evacuation population of lava flow risk in the two scenarios is similar;the potential evacuation population of pyroclastic density current in scenario 1 is at least 209000.In terms of potential economic loss,the potential economic loss of volcanic ash risk is the highest.The potential economic loss of scenario 1 is 9.296 billion euro,which is much larger than that of scenario 2 of 4.980 billion euro.However,the potential economic loss of scenario 2 of lava flow risk is4.050 billion euro,which is higher than that of scenario 1 of 3.588 billion euro.This thesis has 39 pictures,22 tables,and 148 references.