RUI: Geophysical Measurements Using Ring Lasers and Arrays

为了贯彻“RUI：使用环形激光和阵列进行地球物理测量”奖的目标，帮助创建推进地球科学研究的基础设施，阿肯色州康威市亨德里克斯学院的本科生们正在研究美国中部地震产生的旋转地面运动、大气次声和密西西比湾的特征。在这些研究中，学生们利用大型环形激光陀螺仪与地震仪和气压计相结合的测量结果，这些仪器是NSF可移动地球示波器阵列的一部分。多年来，地震学家已经知道，地震除了产生垂直和横向的地面运动外，还会产生旋转的地面运动；地震的旋转分量造成的潜在危险还没有完全了解。测量地震波旋转分量的两种方法是使用大型环形激光陀螺仪和地震仪阵列。除了对地震波敏感外，大型环形激光陀螺仪已被证明对大气次声敏感。学生们使用环形激光陀螺仪的测量结果和NSF便携式地球示波器阵列的气压读数来研究飓风、火山、落基山脉上的奇努克风以及海洋驻波中的微气压等现象的次声信号。例如，飓风的次声信号可以提供关于其内部结构的信息，或许还可以提供关于其强度变化的信息。1811年至1812年间，密西西比河沿岸发生的三次大地震震动了美国中部，震中靠近密苏里州新马德里小镇。据估计，震级从略高于7级到接近8级不等。如果再次发生这种规模的地震，可能会对田纳西州孟菲斯等大都市造成灾难性的破坏。为了更好地了解新马德里断层的危险，美国国家科学基金会出资部署了一个密集的地震阵列，以补充国家科学基金会的可移动地球望远镜阵列。亨德里克斯学院的学生正在利用密集阵列的结果进行旋转地震动研究，并在帮助部署密集阵列中的地震仪方面获得了实际的地震学经验。

In keeping with the goal of the "RUI: Geophysical Measurements Using Ring Lasers and Arrays" award to help create an infrastructure for advancing research in the Earth sciences, undergraduate students at Hendrix College in Conway, Arkansas are examining the rotational ground motion generated by earthquakes in the Central United States, atmospheric infrasound, and the characteristics of the Mississippi Embayment. In these studies, the students are utilizing measurements from large ring laser gyroscopes in conjunction with the seismographs and barometric pressure gauges that are part of the NSF Transportable EarthScope Array. Seismologists have known for years that earthquakes generate rotational ground motion in addition to vertical and lateral ground movement; the potential hazards from the rotational components of earthquakes are not completely understood. Two approaches for measuring the rotational components of seismic waves are through the use of large ring laser gyroscopes and arrays of seismographs. In addition to being sensitive to seismic waves, large ring laser gyroscopes have proven to be sensitive to atmospheric infrasound. Measurements from the ring laser gyroscopes and the barometric pressure readings from the NSF Transportable EarthScope Array are in use by the students to study the infrasound signatures from phenomenon as varied as hurricanes, volcanoes, Chinook winds over the Rocky Mountains, and microbaroms from ocean standing waves. As an example, infrasound signatures from hurricanes can provide information about their internal structure and perhaps provide information about their intensity variations. During 1811-1812, three large earthquakes in the Mississippi Embayment shook the Central United States with epicenters close to the small town of New Madrid, Mo. Estimates of the earthquake magnitudes range from slightly above seven to nearly eight. If earthquakes of this magnitude were to reoccur, there could be catastrophic damage to metropolitan areas such as Memphis, TN. In an attempt to better understand the danger from the New Madrid fault, NSF has funded the deployment of a dense seismic array that will supplement the NSF Transportable EarthScope Array. Hendrix College students are using the results from the dense array in their rotation ground motion studies and are gaining hands-on seismological field experience in helping to deploy seismographs in the dense array.