Glacier–volcano interactions in the North Crater of Mt Wrangell, Alaska
Glacier–volcano interactions in the North Crater of Mt Wrangell, Alaska
复制标题
阿拉斯加兰格尔山北火山口的冰川与火山相互作用
DOI：
10.3189/172756407782282462
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发表时间：
2007
影响因子：
2.9
通讯作者：
M. Truffer
中科院分区：
文献类型：
--
作者：
C. Benson;R. Motyka;S. McNutt;M. Lüthi;M. Truffer
摘要1961 - 2005年在兰格尔峰（62.00° N，144.02°W;海拔4317米）进行的冰川学和相关观测，阿拉斯加中南部的一座巨大的冰川覆盖的盾状火山，显示出明显的变化，似乎是由1964年3月27日的阿拉斯加大地震（Mw = 9.2）引发的。直径为4×6公里的山顶火山口充满了冰，边缘有几个后火山口，包括山顶地区，每年的积雪量为1- 2米的水当量，年平均温度，在雪面以下10米处测量，为-20 ° C。精密测量、航空摄影测量以及温度和积雪的测量被用来测量冰川冰的损失，相当于十年内北火山口约0.03立方公里的水。用冰川量热法计算了相关的热通量，其变化范围为20- 140 Wm-2;总热流为20- 100 MW。火山口边缘的地震活动数据显示，在从几分钟到几个月的时间尺度上，大地震有两种不同的反应。水和天然气的化学成分从火山口指示一个浅岩浆热源和地震活动数据与此解释是一致的。
Abstract Glaciological and related observations from 1961 to 2005 at the summit of Mt Wrangell (62.00° N, 144.02°W; 4317m a.s.l.), a massive glacier-covered shield volcano in south-central Alaska, show marked changes that appear to have been initiated by the Great Alaska Earthquake (Mw = 9.2) of 27 March 1964. The 4×6 km diameter, ice-filled Summit Caldera with several post-caldera craters on its rim, comprises the summit region where annual snow accumulation is 1–2m of water equivalent and the mean annual temperature, measured 10 m below the snow surface, is –20°C. Precision surveying, aerial photogrammetry and measurements of temperature and snow accumulation were used to measure the loss of glacier ice equivalent to about 0.03 km3 of water from the North Crater in a decade. Glacier calorimetry was used to calculate the associated heat flux, which varied within the range 20–140Wm–2; total heat flow was in the range 20–100MW. Seismicity data from the crater’s rim show two distinct responses to large earthquakes at time scales from minutes to months. Chemistry of water and gas from fumaroles indicates a shallow magma heat source and seismicity data are consistent with this interpretation.