Facility Support: Pinon Flat Observatory - Longbase Strainmeters Interim Operation

这笔拨款支持皮诺平天文台（PFO）长基线激光应变仪(3)和一个长基线倾斜仪的操作和维护的连续性，为期40个月（与GAGE设施合作协议EAR-1261833的到期一致）。PFO是三个LSM的唯一位置？s允许整个应变张量的测量具有与GPS相匹配的长期稳定性，具有比GPS好几个数量级的短期灵敏度，并且没有校准问题和钻孔应变仪上存在的水文效应。PFO数据（包括一些环境传感器）无与伦比的“时间深度”使得评估一系列新信号和识别只在很长时间内出现的模式成为可能。PFO LSMs检测到由当地地震触发的重复地震信号，在过去22年中观测到7次，并且被认为是由附近圣哈辛托断层的Anza间隙内的地震滑动引起的。LSM数据可以追溯到20世纪70年代初。S，并在改进形式（全锚定）回到80年代中期。PFO LSM时间序列观测在世界上是独一无二的，并且位于贯穿南加州和北加州的转换断层系统的战略区域，对于美国的大量人口基地来说，这仍然是一个严重和潜在的地震危险。真空激光干涉地壳位移梯度测量的极端灵敏度，如PFO，提供了在Anza地震间隙内见证地震前兆的真正可能性。与南、北转换断裂系统的区域相比，安扎断裂带是地震安静的。这个地区当然是潜在的成熟的大地震，虽然它可能是一个地区的转变，适应应变积累主要是通过地震滑动。然而，如果该地区发生大地震，考虑到在2018年9月之后找到其他支持来源之前保持其运行的边际成本，重要的长时间序列PFO LSM数据集的损失将不会太不幸。这种支持与美国国家科学基金会促进科学进步的使命是一致的，并且可以在提高地震危害和减灾知识方面很好地促进国家的健康、繁荣和福利

1533790AgnewThis grant support continuity of operations and maintenance of the Pinon Flat Observatory (PFO) long-baseline laser strainmeters (3) and one long baseline tiltmeter for a period of forty months (congruent with the expiration of the GAGE Facility Cooperative Agreement EAR-1261833). PFO is the only location in which three LSM?s allow the full strain tensor to be measured with a long-term stability that matches GPS, with a short-term sensitivity orders of magnitude better than GPS, and without the calibration concerns and hydrologic effects present on borehole strainmeters. The unmatched "temporal depth" of the PFO data (including a number of environmental sensors) makes it possible to evaluate a range of new signals and to identify patterns which appear only over very long times. PFO LSMs have detected repeated aseismic signals triggered by local earthquakes, observed seven times over the last 22 years, and thought to be caused by aseismic slip within the Anza gap of the nearby San Jacinto Fault. The LSM data extend back to the early 1970?s, and in improved form (fully-anchored) back to the mid-1980?s. The PFO LSM time series observations are unique in the world and are in a strategic area of the transform fault system that runs throughout southern and into northern California and that remains a serious and potent seismic hazard for a large population base in the U.S. The extreme sensitivity of in vacuo laser interferometric crustal displacement gradient measurements such as at PFO offers the real possibility of witnessing seismic precursors within the Anza seismic gap. The Anza gap is seismically quiet compared to regions of the transform fault system to the south and the north. This area is certainly potentially ripe for a major earthquake though it may be an area of the transform that accommodates strain accumulation largely through aseismic slip. However, if a major earthquake in the region should occur, the loss of the important long time series PFO LSM data sets would be less than unfortunate given the marginal costs of keeping it running until other sources of support might be found post-September 2018. This support is congruent with NSFs mission of promoting the progress of science and may well advance the national health, prosperity and welfare in terms of advancing knowledge about seismic hazards and hazard mitigation.***