Infrasonic and Gravity Wave Studies in the Central United States

美国中部的次声波和重力波研究

• 批准号: 1147962
• 负责人: Kristoffer Walker
• 金额: $ 18.01万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-15 至 2014-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1147962&HistoricalAwards=false
• 关键词: Infrasonic; Gravity; Wave; Studies; Central

Infrasonic and Gravity Wave Studies in the Central United StatesSeismometers of the Transportable Array (TA) not only directly measure ground motion due to sources within the Earth's solid interior, they also indirectly provide valuable information about other phenomena that affect ground motion, such as atmospheric infrasound and gravity waves. Recently all 400 sites of the TA were retrofitted with barometers and infrasonic microphones. The Earthscope Science Plan includes as a scientific target the "cryosphere, hydrosphere, and atmosphere". Specifically, "studies of the infrasonic field allow for novel deep sounding of atmospheric structure and facilitate quantitative characterization of volcanic, oceanic, and other infrasonic sources." It has been recently shown that the density of TA sites permits one to accurately locate infrasonic sources, regardless if the infrasonic signals are registered by seismometers or microphones. This project is expanding upon previous Earthscope-funded work on the detection and location of more than 900 infrasonic pressure disturbances, or "skyquakes", that were registered by the seismic USArray during 2007-08 in the western U.S. Specifically, methods are being improved and applied to the seismo-acoustic USArray in the central U.S. Previously undetected skyquakes are being identified as are sources of gravity waves that propagate across the TA. The goals of this project are to identify the occurrence, waveform structure, and propagation statistics of these sources from 01/2009 through 03/2012. Correlations are being made between these events and atmospheric phenomena such as tornadoes and gust fronts. This work is resulting in two new databases of infrasonic and gravity wave event locations, arrival characteristics, and waveforms. The project is also illuminating infrasonic arrival branches in fine detail from several high-quality events.

美国中部的次声和重力波研究可移动阵列(TA)的地震仪不仅直接测量地球固体内部震源引起的地面运动，还间接提供有关影响地面运动的其他现象的宝贵信息，如大气次声和重力波。最近，TA的所有400个地点都安装了气压计和次声麦克风。地球望远镜科学计划将“冰冻圈、水圈和大气层”作为科学目标。具体地说，“次声场的研究允许对大气结构进行新的深度探测，并促进火山、海洋和其他次声来源的定量表征。”最近已经表明，TA站点的密度使人们能够准确地定位次声源，无论次声信号是由地震仪还是麦克风记录的。该项目是在之前由地球望远镜资助的探测和定位900多次次声压力扰动或“天震”工作的基础上进行的，这些工作是由美国地震台阵在2007-08年期间在美国西部记录的。具体地说，正在改进方法，并将其应用于美国中部的地声台阵。以前未检测到的天震被确定为传播到整个塔台的重力波源。本项目的目标是确定2009年1月1日至2012年3月3日期间这些震源的出现情况、波形结构和传播统计数据。这些事件与龙卷风和阵风锋面等大气现象之间存在关联。这项工作正在产生两个新的次声和重力波事件位置、到达特征和波形数据库。该项目还从几个高质量的活动中详细地照亮了次声到达分支机构。