摘要
高温岩浆在上升过程中遇到地下水或地表水发生水岩相互作用,产生大量水蒸汽导致的爆炸式喷发作用,可称为射汽岩浆喷发作用,是一种较为特殊的火山活动,主要产物为低平火山口和基浪堆积物。国内外许多火山学家对射汽岩浆喷发作用的喷发过程和产物开展了岩相学、沉积学、火山物理学和地球化学综合研究,通过实验、计算机模拟等方法探究了射汽岩浆喷发过程的影响因素。文中介绍了国内外研究人员的相关研究成果,以便更好地了解射汽岩浆喷发这种特殊的火山作用形式,以期能将其应用于现代火山灾害预防和监测工作中,保护人们的生命和财产安全。
Phreatomagmatic eruption is a kind of special eruption,which usually occurs when hot magma rises and contacts with the ground water.The water/melt interaction produces explosive eruption and base-surge deposits,which resulted in maars.Monogenetic maar is a common volcano type on continents and islands.This kind of volcanoes is widely distributed in many countries.Researchers have studied eruption process and products of phreatomagmatic eruptions by means of petrological,sedimentological,volcanic physical and geochemical methods and techniques.Additionally,they have also explored influence factors over eruption process through experimental and computer simulations.Phreatomagmatic eruptions can be considered as the natural equivalent of a class of physical processes termed fuel-coolant interactions(FCI)by investigators of large industrial explosions.Initially,a small volume of water is vaporized due to contact with the melt,with pulsating increasing in the high-pressure steam volume within the aquifer,the dominant effect of the vaporization energy is to fragment the melt and country rocks.Subsequently,the steam,melt,and country rock mix and vapor explosion occurs after vaporization energy increases beyond the confinement strength in chamber.Finally,maar and base-surge deposits form when the overlying layer is broken by the impact of the explosion.Two contrasting environments exist with respect to groundwater availability for the phreatomagmatic explosions.1)In hard rock environment,the wall rocks are cut by joints and faults,many of which are hydraulically active.Under such groundwater conditions,a maar-diatreme volcano would form.2)When the magma rises into soft-rock environment rich in water or with high permeability,it will lead to the formation of tuff-rings.Maar consists of the crater at the surface(which is cut into the pre-eruption land surface),the tephra ring surrounding the crater and the cone-shaped diatreme,root zone and feeder underlies the maar crater.This tephra ring is easily eroded in the late evol
作者
张雯倩
李霓
ZHANG Wen-qian;LI Ni(National Observation and Research Station of Jilin Changbaishan Volcano,Institute of Geology,China Earthquake Administration,Beijing 100029,China;Key Laboratory of Seismic and Volcanic Hazards,China Earthquake Administration,Beijing 100029,China)
出处
《地震地质》
EI
CSCD
北大核心
2021年第1期105-122,共18页
Seismology and Geology
基金
国家自然科学基金(41772356)资助。
