The September 16, 2015 Illapel tsunami, Chile – Sedimentology of tsunami deposits at the beaches of La Serena and Coquimbo
The September 16, 2015 Illapel tsunami, Chile – Sedimentology of tsunami deposits at the beaches of La Serena and Coquimbo
复制标题
2015 年 9 月 16 日智利伊拉佩尔海啸 â 拉塞雷纳和科金博海滩海啸沉积物的沉积学
DOI：
10.1016/j.margeo.2016.12.011
复制
发表时间：
2015
期刊：
影响因子：
2.9
通讯作者：
Kreutzer
中科院分区：
文献类型：
--
作者：
Bahlburg;Nentwig;Kreutzer
2015年9月16日，智利中部沿海发生里氏8.3级地震，震中位于伊亚佩尔镇以西46公里处。地震引发的海啸主要影响了火山口城镇之间的海岸。27°S）和Pichidangui（c.南纬32度）。在科金博和拉塞雷纳（c.海啸达到了4.5米的巨浪高度，导致洪水泛滥，包括沿海道路在内的基础设施遭到破坏。我们报告了2015年10月进行的海啸后沉积学实地调查的结果，重点是科金博和拉塞雷纳的海滩。在普拉亚昌加，科金博的海滩受到最高波的影响，海啸摧毁了大部分沿海公路的向海和向陆侧。在向陆地一侧，海啸将三角形的混凝土筑堤构件分散在沿海平原上。在向海一侧，高达2吨的花岗岩巨石被从沿海公路路堤上扯出，并运到海滩上。用于筑堤的沙子作为流出存款重新分布在整个海滩上。在拉塞雷纳，我们观察到海啸沉积层沿着一条垂直于海岸的20 m长的海沟。沉积物具有侵蚀性基底表面，振幅高达50厘米。存款厚度在10和50厘米之间变化。沉积包由6个主要的透镜状层组成，厚度和空间范围各不相同，介于几毫米厚的深色纹层和富含重矿物的浅色砂层之间，厚度可达15厘米。粒度分布为中等分选至分选良好，单峰，模式在1.3和2.0 Φ之间（中砂）。下四层交错层显示海啸流入的沉积，从顶层起第二层交错层记录流出。交错层和纹层的丰富表明，推移质牵引流的沉积作用是主要的沉积方式，水逸构造以小型砂底辟和火山的形式出现。水通过小火山逃逸似乎与牵引沉积形成上覆层是同时代的。这种同步性是由来自下层的沙所指示的，下层沙被保存为在下流中变形的薄羽流，即在新形成的上层中向陆地方向变形。其他沉积层显示，砂底辟侵入上覆海啸存款达15 cm。沉积结构组合表明，海啸事件相关的一个或几个波浪造成了快速沉积。
On September 16, 2015, a Mw 8.3 earthquake occurred off the coast of central Chile, 46 km west of the town of Illapel. The quake caused a tsunami impacting the coast mainly between the towns of Caldera (c. 27°S) and Pichidangui (c. 32°S). At Coquimbo and La Serena (c. 30°S) the tsunami attained large wave heights on the order of 4.5 m leading to flooding and destruction of infrastructure including the coastal road. We report the results of a post-tsunami sedimentological field survey undertaken in October 2015 focussing on the beaches of Coquimbo and La Serena.At Playa Changa, a beach at Coquimbo affected by the highest waves, the tsunami destroyed large parts of the coastal road embankments on both the seaward and landward sides. On the landward side the tsunami distributed triangular concrete construction elements of the embankment across the coastal plain. On the seaward side granite boulders of up to 2 t were ripped out of the coastal road embankment and transported onto the beach. Sand used in construction of the embankment was redistributed across the beach as an outflow deposit.At La Serena we observed a laminated package of tsunami deposits along a 20 m long trench perpendicular to the coast. The sediments have erosive basal surfaces with an amplitude of up to 50 cm. The deposit thickness varies between 10 and 50 cm. The sedimentary package consists of 6 mostly lenticular layers of variable thickness and spatial extent, ranging between dark laminae a few millimeters thick and rich in heavy minerals, and lighter colored sand layers up to 15 cm thick. Grain size distributions are moderately well to well sorted and unimodal with modes between 1.3 and 2.0 Φ (medium sand). Cross-beds in the lower four layers indicate deposition from tsunami inflow, cross bedding in the second layer from the top layer records outflow. The abundance of cross beds and laminae suggests that deposition of sand from bed load traction currents was the prevailing mode of deposition.Water escape structures occur as small sand diapirs and volcanoes. Water escape through small volcanoes appears to have been coeval to formation of the overlying layer by traction deposition. This synchroneity is indicated by sand sourced from the lower layer which has been preserved as a thin plume deformed in the downcurrent, i.e. landward direction in the newly forming upper layer. Other sediment layers show sand diapirs intruding up to 15 cm into the overlying tsunami deposit.The assemblage of sedimentary structures indicates rapid deposition, from one or several waves associated with the tsunami event.
登录
查看更多内容
1960年和2010年智利地震重叠破裂区五个世纪的海啸和地面变化
DOI：
--
发表时间：
2014
期刊：
影响因子：
--
作者：
L. Ely;M. Cisternas;R. Wesson;T. Dura
通讯作者：
T. Dura
干旱硅质碎屑海岸海啸沉积物的保存潜力
影响因子：
12.1
作者：
M. Spiske;J. Piepenbreier;C. Benavente;H. Bahlburg
通讯作者：
H. Bahlburg
DOI：
10.1029/jb094ib01p00665
发表时间：
1989-01-10
期刊：
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS
影响因子：
--
作者：
CIFUENTES, IL
通讯作者：
CIFUENTES, IL
TsuSedMod 反演模型应用于 2004 年苏门答腊岛和 2006 年爪哇海啸的沉积物以及对估计古海啸流动参数的影响
影响因子：
2.8
作者：
Spiske;Bahlburg;Roskosch;Amijaya
通讯作者：
Amijaya
2010 年智利海啸造成的粗碎屑迁移的准实验环境（智利中部布卡莱姆）
DOI：
--
发表时间：
2011
期刊：
影响因子：
--
作者：
M. Spiske;H. Bahlburg
通讯作者：
H. Bahlburg