RAPID: Fault Creep Following the Mw=7.2 Sierra El Mayor Earthquake of 4 April

RAPID：4 月 4 日 Mw=7.2 Sierra El Mayor 地震后断层蠕变

• 批准号: 1039474
• 负责人: Roger Bilham
• 金额: $ 1.51万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2011-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1039474&HistoricalAwards=false
• 关键词: RAPID; Fault; Creep; Following; Mw=7.2

The investigation has as its objective the rapid deployment of instruments sensitive to the movement of faults of southern California and northern Mexico. These faults all lie to the north of the epicenter of the Mw=7.2 Sierra Mayor earthquake of 4 April 2010, which abruptly increased tectonic stress in southern California, bringing three major US fault-systems closer to failure: the Elsinore, San Jacinto and San Andreas systems. Seismologists believe that fault segments within each of these systems could slip in one or more earthquakes greater than Mw=7 resulting in huge economic losses in the US. At least two of segments were already close to failure prior to the recent earthquake. The surface traces of segments of these three fault systems all slipped a minor amount (by a process of triggered creep) in response to the instantaneous stress released by the April earthquake. and some continue to creep in response both to aftershocks, and to the instantaneous stress during the mainshock. The question arises as to which of these three fault systems is most likely to experience failure in a future earthquake, and several remote sensing and local measurements are being undertaken to identify the most significant stress changes that have now occurred.The instrumentation being installed by the present project (starting less than a week after the earthquake) consists of six buried 20' to 60'-long graphite rods installed obliquely across each fault, and attached firmly to the rock on one side, that are drawn through a telescopic plastic pipe should the fault move. A displacement transducer monitors the displacement of the free end of the rod relative to a second anchor on the remote side of the fault to an accuracy of 1/1000 inch. The displacement is measured every 15 minutes and recorded by a local data logger that operates autonomously from AA cells for up to a year. The data are transmitted through a cell phone every 2 hours to a publicly accessible web site where they may be viewed by the scientific community, by transportation and pipeline authorities, and by members of the public. The latency can be decreased to less than 1 minute by remote command, should anomalous seismic slip occur on any of these monitored faults. In such an event the seismological community will be in an informed position to advise the public concerning increased hazards to lifeline interruptions following an earthquake, far sooner than it takes for members of the public or geologists to inspect the epicenter. The website is https://datagarrison.com/ user=geo, password hobo.

调查的目标是快速部署对南加州和北方墨西哥断层运动敏感的仪器。 这些断层都位于2010年4月4日的马约尔山脉Mw=7.2级地震的震中以北，这场地震突然增加了加州南部的构造应力，使美国三大断层系统更接近崩溃：埃尔西诺、圣哈辛托和圣安德烈亚斯系统。 地震学家认为，这些系统中的每个断层段都可能在一次或多次大于Mw=7的地震中滑动，从而导致美国的巨大经济损失。 在最近的地震之前，至少有两个部分已经接近失败。 这三个断层系统的地表痕迹都有轻微的滑动（通过触发蠕变过程），以响应4月地震释放的瞬时应力。有些继续蠕动，以应对余震和主震期间的瞬时应力。 问题是，这三个断层系统中哪一个最有可能在未来的地震中失败，目前正在进行一些遥感和当地测量，以确定目前发生的最重要的应力变化。（地震后不到一周开始）由六个埋在地下的20“至60”长的石墨棒组成，斜穿过每个断层，并牢固地附着在一侧的岩石上，通过一个伸缩的塑料管来抽取断层移动时的能量 位移传感器以1/1000英寸的精度监测杆的自由端相对于断层远端上的第二锚的位移。 每15分钟测量一次位移，并由本地数据记录器记录，该数据记录器从AA电池自动运行长达一年。 这些数据每两小时通过一部手机传送到一个可供公众访问的网站，科学界、运输和管道当局以及公众均可在该网站上查看。 如果在这些监测的断层中的任何一个上发生异常地震滑动，则通过远程命令可以将延迟减少到小于1分钟。 在这种情况下，地震学界将处于知情地位，就地震后生命线中断的危险增加向公众提供咨询，远远早于公众或地质学家检查震中所需的时间。 网址是https://datagarrison.com/ user=geo，密码流浪汉。