Seismological Components of the MELT Experiment on the Southern East Pacific Rise: West Coast OBS Facility Support and Analysis

[403587 . Dorman]这个实验的目的是提供关于融冰分布和洋中脊下上升流模式的直接观测约束。利用海底仪器阵列对地幔中的电磁波和地震波传播进行研究，将提供可以反向测量的数据，以发现速度和电导率结构的水平和垂直变化，这些变化可用于测试流动的理论模型。一个由47个海底地震仪组成的阵列将在南纬17度左右的东太平洋隆起上部署6个月，以记录远震和区域震源。该阵列记录的P波和S波以及其他体波相位以及Love和Rayleigh面波将用于探测距脊轴100至200公里深度和数百公里外的地幔结构的横向变化。主要目标是确定是否在脊轴正下方存在高熔体浓度和低地震速度的狭窄区域，并绘制其垂直和水平范围。另一个目标是限制上升流的模式。＊＊＊

9403587 Dorman This experiment is designed to provide direct observational constraints on the distribution of melt and the pattern of upwelling beneath a mid-ocean ridge. Studies of electromagnetic and seismic wave propagation in the mantle with arrays of oceanbottom instruments will furnish measurements that can be inverted to find horizontal and vertical variations in velocity and conductivity structure that can be used to test theoretical models of flow. An array of 47 ocean-bottom seismometers will be deployed for six months on the East Pacific Rise at about 17 degrees south to record teleseismic and regional earthquake sources. P and S waves, as well as other bady wave phases and Love and Rayleigh surface waves recorded by the array will be used to probe lateral variations in mantle structure to a depth of 100 to 200 km and out to several hundred km from the ridge axis. The main goal is to establish whether there is a narrow region of high melt concentration and low seismic velocities directly beneath the ridge axis and to map its vertical and horizontal extent. Another goal is to constrain the pattern of upwelling. ***