Collaborative Research: Detection and mechanics of sinkhole activities in central Florida

合作研究：佛罗里达州中部天坑活动的检测和机制

• 批准号: 1620617
• 负责人: Shimon Wdowinski
• 金额: $ 24.39万
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-15 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1620617&HistoricalAwards=false
• 关键词: Collaborative; Research; Detection; mechanics; sinkhole

Sinkhole activity in central Florida is a major natural hazard. Over the past several years, two events in particular attracted media attention. In March 2013, a sinkhole collapsed beneath a house in Seffner and "swallowed" a person from his bedroom. In August 2013 a sinkhole collapse destroyed a resort complex near Disney World. These dramatic events, however, are just extreme examples that stand out from a steady stream of about $200 million per year in property damage claims, which spike at times of anthropogenic groundwater withdrawals. Detecting incipient sinkhole activity is a challenging task, because most of the activity occurs in the subsurface. However, in some cases sinkhole activities also induce surface subsidence, which can be detected by space-based Interferometric Synthetic Aperture Radar (InSAR) observations. This project is a follow up of a proof-of-concept project funded by NSF, in which the researchers demonstrated that InSAR observations can detect localized patterns of surface changes in central Florida. However, the detection of slow subsidence using more advanced InSAR time series techniques requires longer span of acquisitions than obtained during the limited duration of the initial project. In this renewal project, we propose to continue the InSAR-based detection of sinkhole activity in central Florida by extending the observation period for two additional years. The longer time series will allow us to reduce the effect of measurement noise and detect localized slow subsidence induced by sinkhole activity. The proposed project also includes geophysical surveys to map sinkhole structure and soil sampling at selected field sites. In addition, a mechanical modeling effort will examine whether, at the field sites, InSAR-detected subsidence is compatible with measured properties of cohesive soils, field data, and simple models for sinkhole subsidence. This modeling method could be used to assess whether observed subsidence represents a likely precursor to collapse.

佛罗里达州中部的天坑活动是一个主要的自然灾害。在过去的几年里，有两件事特别引起了媒体的关注。 2013年3月，塞夫纳一所房子下面的一个天坑塌陷，“吞掉”了卧室里的一个人。 2013 年 8 月，天坑塌陷摧毁了迪士尼世界附近的一个度假村综合体。然而，这些戏剧性的事件只是极端的例子，从每年约 2 亿美元的财产损失索赔中脱颖而出，这些索赔在人为地下水抽取时激增。检测初期的天坑活动是一项具有挑战性的任务，因为大多数活动发生在地下。然而，在某些情况下，天坑活动也会引起地表沉降，这可以通过天基干涉合成孔径雷达（InSAR）观测来检测到。该项目是 NSF 资助的概念验证项目的后续项目，研究人员在该项目中证明 InSAR 观测可以检测佛罗里达州中部地表变化的局部模式。然而，使用更先进的 InSAR 时间序列技术来检测缓慢沉降需要比初始项目有限持续时间内获得的采集跨度更长的采集跨度。在这个更新项目中，我们建议通过将观测期再延长两年，继续对佛罗里达州中部的天坑活动进行基于InSAR的探测。较长的时间序列将使我们能够减少测量噪声的影响并检测天坑活动引起的局部缓慢沉降。拟议项目还包括地球物理调查，以绘制天坑结构图，并在选定的现场进行土壤采样。此外，机械建模工作将检查在现场，InSAR 检测到的沉降是否与粘性土壤的测量特性、现场数据和天坑沉降的简单模型兼容。这种建模方法可用于评估观察到的沉降是否代表可能的塌陷前兆。