Extraordinary sediment delivery and rapid geomorphic response following the 2008–2009 eruption of Chaitén Volcano, Chile
Extraordinary sediment delivery and rapid geomorphic response following the 2008–2009 eruption of Chaitén Volcano, Chile
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2008-2009 年智利柴滕火山喷发后，异常的沉积物输送和快速的地貌响应
DOI：
10.1002/2015wr018250
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发表时间：
2016
影响因子：
5.4
通讯作者：
J. Castro
中科院分区：
文献类型：
--
作者：
J. Major;D. Bertin;T. C. Pierson;A. Amigo;A. Iroumé;H. Ulloa;J. Castro
2008年至2009年智利Chaitén火山喷发的10天爆发期覆盖了邻近的流域，覆盖了几厘米至1米厚的火山灰。随后的熔岩穹顶坍塌产生了火山碎屑流，提供了额外的沉积物。在爆炸活动的减弱阶段，适度的降雨引发了一场非同寻常的泥沙冲刷，迅速使多条河道增加了许多米。距离火山10公里处，Chaitén河河道增加了7米，河流穿过一个沿海城镇。在废弃和被撕裂的航道下方的淤积和三角洲增长使人们能够估计干扰后的牵引-负载运输率。在喷发前测深和三角洲表面生长遥感测量的基础上，得出了三角洲体积的时间序列。2008年5月11日至14日的首次冲刷在Chaitén河口沉积了0.5-1.5×106立方米的泥沙。到5月26日，在河道被撕裂后，第二个三角洲积累了大约2×106立方米的泥沙；到2011年底，它积累了大约11×106立方米的泥沙。堆积沉积物由低密度气孔浮石和岩屑流纹岩砂体组成。河道淤积和三角洲发育速率、河道宽度和假定泥沙堆积密度为1100-1500kgm−3表明，在撕裂(∼14-15日)之前和之后不久，平均牵引输沙率非常高，可能高达数十kg S−1 m−1。从2008年10月到2011年12月，平均牵引输沙率从7 kg−1降至0.4 kg−1。尽管输沙异常频繁，但扰动河道迅速恢复(数年)。
The 10 day explosive phase of the 2008–2009 eruption of Chaitén volcano, Chile, draped adjacent watersheds with a few cm to >1 m of tephra. Subsequent lava‐dome collapses generated pyroclastic flows that delivered additional sediment. During the waning phase of explosive activity, modest rainfall triggered an extraordinary sediment flush which swiftly aggraded multiple channels by many meters. Ten kilometer from the volcano, Chaitén River channel aggraded 7 m and the river avulsed through a coastal town. That aggradation and delta growth below the abandoned and avulsed channels allow estimates of postdisturbance traction‐load transport rate. On the basis of preeruption bathymetry and remotely sensed measurements of delta‐surface growth, we derived a time series of delta volume. The initial flush from 11 to 14 May 2008 deposited 0.5–1.5 × 106 m3 of sediment at the mouth of Chaitén River. By 26 May, after channel avulsion, a second delta amassed about 2 × 106 m3 of sediment; by late 2011 it amassed about 11 × 106 m3. Accumulated sediment consists of low‐density vesicular pumice and lithic rhyolite sand. Rates of channel aggradation and delta growth, channel width, and an assumed deposit bulk density of 1100–1500 kg m−3 indicate mean traction‐load transport rate just before and shortly after avulsion (∼14–15 May) was very high, possibly as great as several tens of kg s−1 m−1. From October 2008 to December 2011, mean traction‐load transport rate declined from about 7 to 0.4 kg−1 m−1. Despite extraordinary sediment delivery, disturbed channels recovered rapidly (a few years).
2008 年 5 月智利 Chaitén 喷发的火山灰地层和喷发量
影响因子：
3.5
作者：
Alfano F
通讯作者：
Alfano F