Gravity Changes and Internal Processes: Some Results Obtained from Observations at Three Volcanoes
Gravity Changes and Internal Processes: Some Results Obtained from Observations at Three Volcanoes
复制标题
重力变化和内部过程：三座火山观测获得的一些结果
DOI：
--
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
C. Gerstenecker
中科院分区：
文献类型：
--
作者：
G. Jentzsch;A. Weise;C. Rey;C. Gerstenecker
时间重力变化提供了关于火山建筑物内部和下方的质量和/或密度变化的信息。三个活火山已被调查;他们中的每一个都与一个板块边界有关：马荣/吕宋/菲律宾，默拉皮/爪哇/印度尼西亚和加莱拉斯/哥伦比亚。观测到的重力变化比先前预期的要小，但意义重大。对于正在调查的三座火山，在观测期间，主要观察到重力增加，范围从1，000 nm−2到1，600 nm −2。出乎意料的是，重力的增加仅限于山顶周围半径为5至8公里的一个相当小的区域。在马荣和默拉皮，并行的全球定位系统测量没有产生重大的海拔变化。这对于解释是至关重要的，因为内部压力变化不会导致表面的显著变形。因此，经典的Mogi模型不能适用于浅部伸展岩浆库。为了限制可能的模型，由于地下水位或土壤水分的变化的吸引力估计沿着示范性的默拉皮的斜坡2-D建模。质量重新分布或密度变化进行了评估，以及更深的流体过程中的通风口，以解释重力变化;结果进行比较，将弹性变形的额外影响的模型。
Temporal gravity changes provide information about mass and/or density variations within and below the volcano edifice. Three active volcanoes have been under investigation; each of them related to a plate boundary: Mayon/Luzon/Philippines, Merapi/Java/Indonesia, and Galeras/Colombia. The observed gravity changes are smaller than previously expected but significant. For the three volcanoes under investigation, and within the observation period, mainly the increase of gravity is observed, ranging from 1,000 nm−2 to 1,600 nms−2. Unexpectedly, the gravity increase is confined to a rather small area with radii of 5 to 8 km around the summit. At Mayon and Merapi the parallel GPS measurements yield no significant elevation changes. This is crucial for the interpretation, as the internal pressure variations do not lead to significant deformation at the surface. Thus the classical Mogi-model for a shallow extending magma reservoir cannot apply. To confine the possible models, the attraction due to changes of groundwater level or soil moisture is estimated along the slope of Merapi exemplarily by 2-D modelling. Mass redistribution or density changes were evaluated within the vent as well as deeper fluid processes to explain the gravity variations; the results are compared to the model incorporating the additional effect of elastic deformation.