Rifting of the plate boundary in north Iceland 1975–1978
Rifting of the plate boundary in north Iceland 1975–1978
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1975-1978 年冰岛北部板块边界裂谷
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
E. Tryggvason
中科院分区：
文献类型：
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作者：
Axel Björnsson;G. Johnsen;S. Sigurdsson;Gunnar Thorbergsson;E. Tryggvason
经过100年的沉寂，1975年在冰岛北部的板块边界上开始了一次裂谷活动。在Krafla火山口和相关的80公里长的裂缝群中观测到大约3米的水平延伸。裂谷以短的活动脉冲周期性地发生，间隔几个月。在这些活跃的脉冲之间，由于岩浆以5米/秒的速度流入3公里深的岩浆库，火山口以7- 10毫米/天的速度持续膨胀。活动脉冲是由裂缝群突然的东西向扩张和裂缝群外带的收缩引起的。岩浆从岩浆房中迅速流出，向北或向南流入裂缝。这些脉冲伴随着地震群和高达2米的垂直地面运动，有时还伴随着火山爆发和新喷气孔的形成。因此，克拉夫拉火山口下方的岩浆房在冰岛北部沿构造板块边界的板块运动中起着触发作用。
A rifting episode started in 1975 on the accreting plate boundary in North Iceland after 100 years of quiescence. Horizontal extension of some 3 m has been observed in the Krafla caldera and the associated 80 km long fissure swarm. The rifting occurs periodically in short active pulses at a few months intervals. Between these active pulses, continuous inflation of 7--10 mm/day of the caldera is caused by 5 m/sup 3//s inflow of magma into a magma chamber at 3 km depth. The active pulses are caused by a sudden east-west expansion of the fissure swarm and a contraction of zones outside the fissure swarm. Rapid flow of magma out of the magma chamber and into the fissures toward north or south is indicated. These pulses are accompanied by earthquake swarms and vertical ground movements of up to 2 m and sometimes also volcanic eruptions and formation of new fumaroles. The magma chamber below the Krafla caldera thus acts as a trigger for the plate movement along the constructive plate boundary in North Iceland.