Use of Digital Aerophotogrammetry to Determine Rates of Lava Dome Growth, Mount St. Helens, Washington, 2004-2005
Use of Digital Aerophotogrammetry to Determine Rates of Lava Dome Growth, Mount St. Helens, Washington, 2004-2005
复制标题
使用数字航空摄影测量法确定熔岩穹顶的生长速度，华盛顿州圣海伦斯山，2004-2005 年
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
E. Iwatsubo
中科院分区：
文献类型：
--
作者：
S. Schilling;Ren A. Thompson;J. Messerich;E. Iwatsubo
从2004年10月开始，华盛顿圣海伦火山冰川覆盖的火山口底部出现了一个新的熔岩穹丘，就在20世纪80年代熔岩穹丘的南面。十七个数字高程模型（DEM）从垂直航空照片构建提供了定量估计的挤压熔岩体积和总体积变化。为了提取体积变化和计算体积挤出率（岩浆排放率），每个DEM表面进行了比较，从1986年和2003年喷发前DEM参考表面。在2004- 2005年火山爆发的早期，DEM记录了变形的冰川冰和火山口底部，形成了一个突出的“welt”，体积为10× 106 m3，增长率为8.9 m3/s，2004年10月11日英安岩熔岩首次出现在地表。之后，速率最初为5.9 m 3 /s，但到2005年1月初降至2.5 m 3 /s。在2005年期间，挤压速率逐渐下降到约0.7m3/s。到2005年12月15日，新的圆顶建筑群长约900米，宽约625米，高出2003年的地表190米。超过73 x106 m3的英安岩熔岩已经挤压到火山口底部。在火山爆发的最早关键阶段，航空摄影测量的成功应用是可能的，因为我们在火山爆发之前就有了基线数据和摄影测量基础设施。垂直航空照片，包括DEM和从它们衍生的计算，是在2004-5年火山爆发期间收集的最广泛使用的数据集之一，这在本卷的许多贡献中得到了证明。这些数据被用来构建摄影地质图，变形矢量场，并不断变化的圆顶和冰川的配置文件。挤出量和速率被证明是限制喷发动力学模型和假设的关键参数，从而有助于评估火山危险。
Beginning in October 2004, a new lava dome grew on the glacier-covered crater floor of Mount St. Helens, Washington, immediately south of the 1980s lava dome. Seventeen digital elevation models (DEMs) constructed from vertical aerial photographs have provided quantitative estimates of extruded lava volumes and total volume change. To extract volumetric changes and calculate volumetric extrusion rates (magma discharge rates), each DEM surface was compared to preeruption DEM reference surfaces from 1986 and 2003. Early in the 2004-5 eruption, DEMs documented deforming glacier ice and crater floor that formed a prominent "welt" having a volume of 10×10 6 m 3 and a growth rate of 8.9 m 3 /s before dacite lava first appeared at the surface on October 11, 2004. Afterward, the rate was initially 5.9 m 3 /s but slowed to 2.5 m 3 /s by the beginning of January 2005. During 2005, the extrusion rate declined gradually to about 0.7 m 3 /s. By December 15, 2005, the new dome complex was about 900 m long and 625 m wide and reached 190 m above the 2003 surface. More than 73x 10 6 m 3 of dacite lava had extruded onto the crater floor. Successful application of aerophotogrammetry was possible during the critical earliest parts of the eruption because we had baseline data and photogrammetric infrastructure in place before the eruption began. The vertical aerial photographs, including the DEMs and calculations derived from them, were one of the most widely used data sets collected during the 2004-5 eruption, as evidenced in numerous contributions to this volume. These data were used to construct photogeologic maps, deformation vector fields, and profiles of the evolving dome and glacier. Extruded volumes and rates proved to be critical parameters to constrain models and hypotheses of eruption dynamics and thus helped to assess volcano hazards.