Cataclysmic eruptions in densely populated areas: the ticking eruptive clock at Popocatepetl volcano (Mexico).

GSTDTAP

项目编号	NE/M014584/1
	Cataclysmic eruptions in densely populated areas: the ticking eruptive clock at Popocatepetl volcano (Mexico).
	[unavailable]
主持机构	The Natural History Museum
项目开始年	2015
	2015-02-23
项目结束日期	2018-02-22
资助机构	UK-NERC
项目类别	Research Grant
国家	英国
语种	英语
英文摘要	Andesitic stratovolcanoes are the most explosive volcanoes on our planet. On a societal level, they have great impact on the proximal region and human population, whilst on a larger Earth system scale, they affect climate and are thought to be key to the evolution of continental crust. The timescales over which an explosive andesitic stratovolcano switches from low-to-moderate explosive activity to cataclysmic Plinian eruption are fundamental in assessing volcanic hazards and safeguarding the lives of threatened human populations. Popocatépetl (Popo) volcano in Mexico is one of the most explosive andesitic stratovolcanoes in North America and one of the ten most populated active volcanoes in the world, threatening an overpopulated area (>20 million) including Mexico City. Its volcanic and magmatic history is well known and is characterised by a wide range of eruption styles including catastrophic Plinian events, effusive activity and moderate explosive Vulcanian activity separated by long but variable periods of quiescence. Key uncertainties at Popo (and in similar volcanoes) are the timescales over which the volcano reactivates or changes eruptive styles and whether these timescales relate to magma recharge of the system. The proposed work addresses these uncertainties via the following over-arching questions: 1) How and on what timescale do intermediate stratovolcanoes change their eruptive behaviour from low-to-moderate explosive activity to catastrophic Plinian eruption? 2) What (if any) is the relationship between timescales, eruptive style and magma recharge flux? Popo represents a natural laboratory to answer these questions: by linking timescales derived from a variety of geochemical techniques to explore crystal residence times and crystal isotope stratigraphies we can determine the main cause(s) of the switch from moderate explosive eruption to highly-explosive catastrophic Plinian activity and inform hazard assessment on the timescales of magmatic proesses and durations of quiescence that can be expected for different eruptive styles. We investigate the existing paradigm that an invers causal relationship exists between the flux of magma injection (i.e., frequency of mixing) and magnitude of volcanic eruption, at a constant crustal magma-supply rate. If flux of magma injection is directly related to explosive magnitude, then we would expect lower frequency of injection to eventually result in more explosive activity. Conversely, periods of high frequency of injection would be predicted to result in more effusive activity. A key question, therefore, is whether a distinct decrease in mixing frequency can be geochemically identified leading up to an explosive Plinian event? We propose an innovative, multi-proxy approach combining crystal residence time and crystal isotope stratigraphy to provide a critical step forward in understanding past eruptive behaviour at Popo. Thus this work will enhance volcanic hazard assessment and provide a guideline for similar volcanic systems.
来源学科分类	Natural Environment Research
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/85507
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	[unavailable].Cataclysmic eruptions in densely populated areas: the ticking eruptive clock at Popocatepetl volcano (Mexico)..2015.