NERC Urgency Sulawesi tsunami 2018

NERC 紧急 2018 年苏拉威西海啸

基本信息

批准号：
NE/S015930/1
负责人：
David Tappin
金额：
$ 8.27万
依托单位：
British Geological Survey
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FS015930%2F1
关键词：
NERC Urgency Sulawesi tsunami 2018

项目摘要

At 6pm local time on the September 28th 2018, a strike-slip earthquake, Mw 7.5, struck the west of Sulawesi Island in Indonesia. Earthquake shaking immediately destroyed large areas of Palu City, the nearest large town of 135,000 people. Further damage was caused by liquefaction of underlying, fine-grained fluvial sediments, which mobilised mudslides that swept through the city. Soon after the earthquake, tsunamis, with elevations of up to 11 m inundated local coastlines causing further destruction, especially to Palu City, and Donggal farther north. At present, 2,100 people are known to have died in the event with over 700 missing. A significant number of these died in the tsunamis.Recent tsunamis provide critical information on mechanisms and impacts which provide essential data on informing on hazard and risk. The mechanism of the Sulawesi earthquake is significant because it is different to recent devastating events, such as Papua New Guinea (1998), Indian Ocean (2004) and Japan (2011), which were triggered by thrust faulting. Sulawesi is a strike-slip rupture with dominantly horizontal movement. Present understanding of earthquake tsunami generation suggests that, because of the absence of significant vertical seabed elevation, it should not have generated the recorded (up to 11m) tsunamis. Preliminary numerical tsunami modelling confirms this understanding. An additional tsunami mechanism is required, and submarine landslides are most likely. Numerical modelling of tsunamis require validation from field observations to confirm their accuracy. These observations have to be made as soon as possible after impact because much of the evidence on the tsunami and its' scale is extremely fragile and short-lived. For example, the directions of flow may be identified by flattened grass; tsunami flow depth and elevation may be identified from water marks on buildings or building damage, vegetation stripping and debris caught in trees or bushes. Sediment deposited, especially in monsoonal conditions, is rapidly eroded or removed. It is vital therefore that after a major tsunami, field observations are made and the research carried out as soon as practicable. Here, for Sulawesi, we propose an urgent response field survey, based on pre-survey interpretations of before and after high-resolution satellite imagery. The results will identify in detail geographical variations on tsunami inundation which will inform on the impact, potential tsunami mechanisms and offer validation for numerical tsunami models. This methodology (desk study followed by field work) was successfully applied to the Japan 2011 tsunami, and is a first critical step towards developing an integrated system for interoperable digital field data collection. From the present field surveys there is information over much, but not all, of the area impacted by the tsunami (see 2). There is a close correlation between the offshore strike-slip rupture (mapped from remote - inSAR data) and field evidence for a tsunami from inundation measurements. There is also correlation between the offshore rupture and coastal subsidence, which supports coastal/submarine landslides as the tsunami mechanism. For the proposed survey, PI Tappin leads an international and multidisciplinary initiative (UK, Indonesia, US and Poland) to study the Sulawesi tsunami. This approach is most likely to fully understand the event, and is required because, at present tsunami warning in Indonesia is based on far-field earthquakes. Locally triggered events, such as Sulawesi, where there was minimal warning, are not at present addressed. More broadly, the project will contribute to an improved understanding of locally, strike-slip triggered, submarine landslide tsunamis and their hazard. The project will inform on improved mitigation strategies in this context. The research will form the basis for future, more in depth research.

2018年9月28日，当地时间下午6点，MW 7.5的滑坡地震袭击了印度尼西亚苏拉威西岛的西部。地震摇晃立即摧毁了帕卢市的大区域，帕卢市最近有135,000人。进一步的损害是由基础，细粒的河流沉积物的液化造成的，这些沉积物动员了穿过城市的泥石流。地震发生后不久，海啸后不久，海拔高达11 m的当地海岸线，造成进一步的破坏，尤其是对帕鲁市和北部的东gal。目前，众所周知，有2100人死亡，失踪了700多人。其中大量在海啸中丧生。截止海啸提供了有关机制和影响的关键信息，这些信息提供了有关危害和风险的重要数据。苏拉威西地震的机制很重要，因为它与最近的毁灭性事件不同，例如巴布亚新几内亚（1998年），印度洋（2004）和日本（2011），这些事件是由推力断层引起的。 Sulawesi是一种具有主要水平运动的滑滑破裂。目前对地震海啸产生的理解表明，由于没有明显的垂直海床高程，因此不应产生记录的（最多11m）海啸。初步数值海啸建模证实了这一理解。需要额外的海啸机制，并且很可能是海底滑坡。海啸的数值建模需要从现场观测值验证以确认其准确性。这些观察结果必须在影响后尽快进行，因为海啸及其规模的许多证据非常脆弱和短暂。例如，流动的方向可以通过扁平的草识别。可以从建筑物或建筑物损坏，植被剥离和在树木或灌木丛中捕获的碎屑的水痕迹来确定海啸的流量深度和高程。沉积的沉积物，尤其是在季风条件下，迅速侵蚀或去除。因此，至关重要的是，在主要的海啸之后，进行了现场观察，并在可行的过程中尽快进行了研究。在这里，对于Sulawesi，我们根据对高分辨率卫星图像之前和之后的调查前解释提出了一项紧急响应现场调查。结果将详细识别海啸淹没的地理变化，这将为影响，潜在的海啸机制提供信息，并为数值海啸模型提供验证。这种方法（桌面研究随后进行现场工作）成功地应用于日本2011海啸，这是开发用于互操作数字现场数据收集的集成系统的第一步。从目前的现场调查中，有很多但不是全部受到海啸影响的区域的信息（请参阅2）。离岸滑移破裂（由遥控数据映射）与淹没测量值海啸的现场证据之间存在密切的相关性。离岸破裂与沿海沉降之间也存在相关性，后者支持沿海/海底滑坡作为海啸机制。在拟议的调查中，Pi Tappin领导了一项国际和多学科倡议（英国，印度尼西亚，美国和波兰），研究Sulawesi Tsunami。这种方法最有可能充分理解这一事件，因此是必需的，因为目前印度尼西亚的海啸警告是基于远场地震。目前尚未解决当地触发的事件，例如苏拉威西（Sulawesi），那里的警告最少。从更广泛的角度来看，该项目将有助于改善对当地，滑滑的理解，触发的潜艇海啸及其危害。在这种情况下，该项目将告知改进的缓解策略。这项研究将构成未来的基础，更多的深入研究。