Unprecedented pressure increase in deep magma reservoir triggered by lava‐dome collapse
Unprecedented pressure increase in deep magma reservoir triggered by lava‐dome collapse
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DOI：
10.1029/2005gl024870
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发表时间：
2006-02
影响因子：
5.2
通讯作者：
B. Voight;A. Linde;I. Sacks;G. Mattioli;R. Sparks;D. Elsworth;D. Hidayat;P. Malin;E. Shalev;C. Widiwijayanti;S. Young;V. Bass;A. Clarke;P. Dunkley;W. Johnston;N. McWhorter;J. Neuberg;P. Williams
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作者：
B. Voight;A. Linde;I. Sacks;G. Mattioli;R. Sparks;D. Elsworth;D. Hidayat;P. Malin;E. Shalev;C. Widiwijayanti;S. Young;V. Bass;A. Clarke;P. Dunkley;W. Johnston;N. McWhorter;J. Neuberg;P. Williams
2003年7月蒙特塞拉特苏弗里耶尔山火山熔岩穹丘坍塌，是有史以来全世界最大的此类事件。在这里，我们报告的钻孔压力计数据记录了一个显着的和前所未有的快速（600 s）加压的岩浆房，触发了这个表面的崩溃。腔室膨胀由近测点处的膨胀偏移和远测点处的收缩指示。通过分析应变数据，并使用来自实验岩石学和GPS大地测量的长期建筑物变形的附加约束，我们倾向于在火山口下方约6 km深度处的源，超压增加1 MPa，平均半径为1.5 km。加压是由于增长的1-3%的气泡在过饱和岩浆，触发的动力学表面卸载。最近的模拟表明，从气泡生长的压力恢复可以超过初始压降近一个数量级。
The collapse of the Soufrière Hills Volcano lava dome on Montserrat in July 2003 is the largest such event worldwide in the historical record. Here we report on borehole dilatometer data recording a remarkable and unprecedented rapid (∼600s) pressurisation of a magma chamber, triggered by this surface collapse. The chamber expansion is indicated by an expansive offset at the near dilatometer sites coupled with contraction at the far site. By analyzing the strain data and using added constraints from experimental petrology and long‐term edifice deformation from GPS geodesy, we prefer a source centered at approximately 6 km depth below the crater for an oblate spheroid with overpressure increase of order 1 MPa and average radius ∼1 km. Pressurisation is attributed to growth of 1–3% of gas bubbles in supersaturated magma, triggered by the dynamics of surface unloading. Recent simulations demonstrate that pressure recovery from bubble growth can exceed initial pressure drop by nearly an order of magnitude.