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

该调查的目标是快速部署对南加州和墨西哥北部断层运动敏感的仪器。 这些断层均位于 2010 年 4 月 4 日发生的 Mw=7.2 Sierra Mayor 地震震中以北，这次地震突然增加了南加州的构造应力，使美国三大断层系统：埃尔西诺、圣哈辛托和圣安德烈亚斯系统更接近崩溃。 地震学家认为，这些系统中的断层段可能会在一次或多次大于 Mw=7 的地震中滑动，从而给美国造成巨大的经济损失。 在最近的地震之前，至少有两个部分已经接近失效。 为了响应四月份地震释放的瞬时应力，这三个断层系统段的表面痕迹都发生了少量滑动（通过触发蠕变过程）。有些会因为余震和主震期间的瞬时应力而继续蠕变。 问题是，这三个断层系统中的哪一个最有可能在未来的地震中发生故障，并且正在进行一些遥感和本地测量，以确定目前已经发生的最显着的应力变化。当前项目安装的仪器（地震后不到一周开始）由六个埋藏的 20' 至 60' 长的石墨棒组成，倾斜地安装在每个断层上，一侧牢固地固定在岩石上，如果断层移动，则通过伸缩塑料管将其拉出。 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的第二个锚的位移。 每 15 分钟测量一次位移，并由本地数据记录仪记录一次，该数据记录仪通过 AA 电池自主运行长达一年。 这些数据每 2 小时通过手机传输到一个可公开访问的网站，科学界、运输和管道当局以及公众都可以在该网站上查看这些数据。 如果这些监测到的断层上发生异常地震滑动，则可以通过远程命令将延迟时间缩短至不到 1 分钟。 在这种情况下，地震界将能够在知情的情况下就地震后生命线中断的危险增加向公众提出建议，这比公众或地质学家检查震中所需的时间要早​​得多。 网站是https://datagarrison.com/user=geo，密码hobo。

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.