Reconnaissance Investigation of Caribbean Extreme Wave Deposits--Preliminary Observations, Interpretations, and Research Directions
Reconnaissance Investigation of Caribbean Extreme Wave Deposits--Preliminary Observations, Interpretations, and Research Directions
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加勒比极端波浪沉积物勘察--初步观测、解释和研究方向
DOI：
10.3133/ofr20061293
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发表时间：
2006
影响因子：
--
通讯作者：
G. Gelfenbaum
中科院分区：
文献类型：
--
作者：
R. Morton;B. Richmond;B. Jaffe;G. Gelfenbaum
封面照片-2006年3月博内尔北部海岸博卡科科利希的全景图显示(从左至右)加勒比海、现代海蚀崖、高架岩石平台上散落的巨石和沙子沉积物以及古Seacliff。海浪席卷区域和新鲜沙子沉积是2004年9月伊万飓风的产物。摘要本报告概述了加勒比地区与沿海灾害有关的初步地质调查和建议的未来研究活动，重点是确定美国领土的海啸风险。2006年3月在波多黎各博内尔岛和瓜德罗普岛进行了实地考察，以评估极端海浪沉积的地层记录，以此作为古海啸复发的可能指标。形态、沉积学和地层学证据表明，海岸平行的珊瑚碎石沉积由10米宽、几米厚的粗碎屑和沙组成，是几个世纪或几千年来积累的沉积杂岩，并不完全像以前报道的那样是一次或几次海啸的结果。加勒比海岛屿高架岩石平台上的巨石场的起源比山脊复合体的起源更复杂，因为巨石场可以由风暴或海啸构成。现在需要的是一种系统的沉积学方法来进行沉积分析，以及一套区分粗碎屑风暴和海啸沉积的标准，以便作出更确凿的解释。收集更多来自加勒比海其他岛屿的现场数据，分析波多黎各和博内尔的地层沉积，并调查历史海啸造成的巨石矿藏，可以实现这一点。还需要改进的粗碎屑沉积物输送模型，可用于估计海啸和风暴的能力和能力，并确定沉积物是否可能是由海啸或极端风暴造成的。改进后的模型对于重建极端海浪事件的震级也可能有用。
Cover photograph – Panorama view on the north coast of Bonaire at Boka Kokolishi in March 2006 showing (from left to right), Caribbean Sea, modern sea cliff, scattered boulders and sand deposits on an elevated rock platform, and a paleo-seacliff. Wave swept zone and fresh sand deposits were products of Hurricane Ivan in September 2004. SUMMARY This report presents an overview of preliminary geological investigations and recommended future research activities in the Caribbean region pertaining to coastal hazards with an emphasis on establishing tsunami risk for U.S. territories. Fieldwork was conducted in March 2006 on the islands of Bonaire, Puerto Rico, and Guadeloupe to evaluate the stratigraphic records of extreme wave deposits as possible indicators of paleotsunami recurrence. Morphological, sedimentological, and stratigraphic evidence indicate that shore-parallel coral rubble deposits composed of coarse clasts and sand that are 10s of meters wide and several meters thick are depositional complexes that have accumulated for a few centuries or millennia, and are not entirely the result of one or a few tsunamis as previously reported. The origins of boulder fields on elevated rock platforms of the Caribbean islands are more complicated than the origins of ridge complexes because boulder fields can be constructed by either storm waves or tsunamis. What is needed now for more conclusive interpretations is a systematic sedimentological approach to deposit analysis and a set of criteria for distinguishing between coarse clast storm and tsunami deposits. Assembling more field data from other Caribbean islands, analyzing stratigraphic deposits on Puerto Rico and Bonaire, and investigating boulder field deposits resulting from a historical tsunami can accomplish this. Also needed are improved sediment transport models for coarse clasts that can be used to estimate the competence and capacity of tsunamis and storms waves and to determine whether a deposit likely was created by a tsunami or extreme storm. Improved models may also be useful for reconstructing the magnitude of extreme wave events.