Intelligent Sensor Motes for Vertical Seismic Arrays

这一行动是为了支持在加州大学伯克利分校校园安装垂直地震阵列。 将在海沃德断层两侧安装两个仪表钻孔。 每个钻孔将由三分量加速度计单元、速率陀螺仪、磁力计和孔隙压力传感器组成。 传感器将是一系列基于MEMS的设备，包括一个全数字24位加速度计。 这些传感器将被纳入一个智能网络传感器Mote。 事件驱动的TinyOS用于跨该单个控制器多路复用并发信息流，该单个控制器连接到收发器、辅助存储设备、面向传感器的I/O系统和电源管理子系统。 该阵列的本底噪声约为30 ng/root（Hz），成本比现有的垂直阵列低2个数量级。近年来，垂直阵列已在加州、台湾和日本的几个站点上线。 他们正在通过允许地震波传播的三维评估来改变对地震地面运动的理解。 井下记录的地面运动提供了一个一瞥波是如何在地球表面附近传播。 通过比较多个井下记录和相关的地面记录，可以观察波在穿过地面时如何变化，以及受土壤剖面中材料的影响。 该阵列允许对场地的实验格林函数进行估计，并使用系统识别的丰富领域进行估计。也许最重要的是，该项目还将向土木工程专业的学生介绍传感器，通信和信息技术的新发展，并帮助他们熟悉多学科工具，并意识到其他工程领域的进步所带来的影响，以及这些技术如何帮助他们解决土木工程问题。

This action is to support the installation of a vertical seismic array on the UC Berkeley campus. Two instrumented boreholes will be installed on either side of the Hayward Fault. Each borehole will consist of 3-component accelerometer units, a rate gyroscope, magnetometer, and pore pressure sensor. The sensors will be an array of MEMS-based devices, including an all-digital 24-bit accelerometer. The sensors will be incorporated into an intelligent networked sensor Mote. An event driven TinyOS is used to multiplex the concurrent flows of information across this single controller, which is connected to a transceiver, a secondary storage device, a sensor oriented I/O system, and a power management subsystem. The noise floor of the array is expected to be approximately 30 ng/root(Hz), and the cost about 2 magnitudes less than current vertical arrays.In recent years, vertical arrays have come on-line in several sites in California, Taiwan, and Japan. They are changing the understanding of seismic ground motion by allowing for the 3-D evaluation of seismic wave propagation. Downhole recordings of ground motion provide a glimpse of how waves are propagating near the surface of the earth. By comparing multiple downhole recordings and a related surface recording, it is possible to observe how the waves change as they progress through the ground and are affected by materials in the soil profile. The arrays allow the estimation of experimental Greens functions for a site, with the estimation made using the rich field of system identification.Perhaps most importantly, the project will also introduce civil engineering students to new developments in sensor, communications, and information technologies, and to help them to become familiar with multi-disciplinary tools, and to become aware of the implications of advances in other fields of engineering, and how these technologies might help them solve civil engineering problems.