Development of Deep Shear Wave Velocity Profiles at Seismic Stations in the Mississippi Embayment

This project contains the raw unprocessed active and passive surface wave data collected near nine seismic stations situated in the Mississippi Embayment. Surface wave data were recorded at the following seismic station sites: Central United States Seismic Observatory (CUSSO), HBAR, HENM, LNXT, LPAR, PARM, PEBM, PVMO, and TUMT. In addition, downhole seismic testing was conducted at the CUSSO site in two stages: preliminary shallow testing to 115 m and deep testing to 425 m. Shallow and deep downhole testing was conducted in the 259 meter and 587 meter deep holes, respectively. In this project, each seismic station folder contains the unprocessed surface wave data and the metadata file. The active surface wave data were recorded at each site using a linear array of 24, 4.5 Hz geophones with 2 m receiver spacing. Both vertical and horizontal geophones were used to record Rayleigh and Love waves, respectively. A 2 m source offset was used for P-wave refraction, whereas multiple source offsets of 5, 10, 20, and 40 m were used for the multichannel analysis surface wave (MASW) data. The passive microtremor array measurements (MAM) data were recorded using circular and L-shaped arrays. The circular array MAM measurements utilized nine three-component Trillium Compact, 20-second broadband seismometers. In each circular array arrangement, eight seismometers were uniformly distributed on the circumference, while the ninth seismometer was placed on the center. Circular arrays of 50 m, 200 m, and 500 m diameter were used at all sites. The L-array MAM measurements were carried out using 24, 4.5 Hz vertical geophones. An equal receiver spacing of 5 m was used, which resulted in an L-array with dimensions of 55 m x 60 m at most sites. The data was used to develop shear wave velocity profiles at these seismic station to bedrock which varied from 427 m to 923 m. The results of the study can be found in the following USGS funded project technical report- “Development of deep shear wave velocity profiles at seismic stations in the Mississippi Embayment”. The details of the recorded data are provided in the metadata files.

本项目包含采集于密西西比河沿岸盆地（Mississippi Embayment）9个地震台站附近的未处理主动与被动面波原始数据集。所记录面波数据的台站包括：美国中部地震观测台（Central United States Seismic Observatory, CUSSO）、HBAR、HENM、LNXT、LPAR、PARM、PEBM、PVMO及TUMT。

此外，研究团队于CUSSO台站开展了两阶段井下地震测试：分别为深度达115米的初步浅层测试，以及深度达425米的深层测试；而浅层与深层井下测试分别在深度259米与587米的钻孔中完成。

本项目中，每个地震台站文件夹均存储有未处理的面波数据与元数据文件。主动面波数据通过由24台4.5Hz检波器组成的线性阵列采集，接收器间距为2米。其中垂直检波器与水平检波器分别用于记录瑞利波（Rayleigh wave）与勒夫波（Love wave）。针对P波折射测试，采用2米震源偏移距；而多道面波分析（Multichannel Analysis of Surface Waves, MASW）数据则采用5米、10米、20米及40米的多组震源偏移距。

被动微震阵列测量（Passive Microtremor Array Measurements, MAM）数据通过圆形与L形阵列采集。圆形阵列MAM测量使用9台三分量Trillium Compact型20秒宽带地震计：每一轮圆形阵列布设中，8台地震计均匀分布于圆周之上，第9台安置于圆心位置。所有台站均采用直径分别为50米、200米与500米的圆形阵列。L形阵列MAM测量则使用24台4.5Hz垂直检波器，接收器间距统一为5米，多数台站的L形阵列尺寸可达55米×60米。

本数据集用于构建这些地震台站至基岩的剪切波速度剖面，目标基岩埋深介于427米至923米之间。本研究的相关成果可参阅由美国地质调查局（USGS）资助的项目技术报告："Development of deep shear wave velocity profiles at seismic stations in the Mississippi Embayment"。所记录数据的详细信息已在元数据文件中予以说明。