Near-surface geophysical data collected in the Sunflower Drain study area near Delta, Colorado, March 2018

Near-surface geophysical surveys were conducted during March 2018 in an irrigated agricultural drainage near Delta, Colorado, locally know as Sunflower Drain. This data release presents results of two surveys, one using fiber-optic distributed temperature sensing (FO-DTS) and the second using a horizontal-to-vertical spectral ratio (HVSR) passive seismic method. For the FO-DTS, a temperature sensitive armored cable with a spatial resolution of 3.31 feet (1.01 meter) was deployed along a 0.3 mile reach of Sunflower Drain. Data were collected and processed using an Oryx model SR Remote Logging DTS unit (Sensornet, 2020) run over a 48-hour period and integrated at 10-minute intervals. The DTS data are provided in two comma separated values (csv) files, one with raw values extracted from the instrument files (DTS_raw.csv) and a second with georeferenced minimum and average temperature data along the cable (DTS_summary.csv). Thirteen HVSR measurements were acquired at 8 sites within the study area using a MoHo Tromino Model TEP-3C three-component seismometer (MoHo, 2020). The HVSR method requires a measurement or estimate of shear-wave velocity, which depends on sediment composition and density, for the conversion of measured resonance frequency to a depth to bedrock (Lane and others, 2008). The shear-wave velocity was estimated from a HVSR measurement made adjacent to an observation well (Poly 7, U.S. Geological Survey (USGS) station 384428107573901) with a well log (Thomas and others, 2019). Data provided in the 'HVSR_saf_files.zip' folder includes the raw HVSR data in SESAME ASCII format version 1 (SAF), showing the three-component time-series trace data for 1 vertical and 2 horizontal (north [N] and east [E]) components. The processed HVSR data for 6 sites shown in figure 12 of Mast (2020) are also included in pdf format in the 'Proccessed_HVSR.zip' folder.

2018年3月，于美国科罗拉多州德尔塔市附近一处当地俗称“向日葵排水沟”的灌溉农业排水沟区域开展了近地表地球物理勘探（Near-surface geophysical surveys）。本数据集发布包含两项勘探的结果：其一采用光纤分布式温度传感（fiber-optic distributed temperature sensing, FO-DTS）技术，其二采用水平-垂直谱比（horizontal-to-vertical spectral ratio, HVSR）被动地震法。针对光纤分布式温度传感勘探，我们沿向日葵排水沟0.3英里的区段布设了一根空间分辨率为3.31英尺（1.01米）的温控铠装电缆。数据采集与处理采用Oryx型SR远程测井分布式温度传感单元（Sensornet公司，2020年），采集时长为48小时，数据以10分钟为间隔进行整合。本次分布式温度传感数据以两个逗号分隔值（comma separated values, CSV）文件形式提供：其一为从仪器文件中提取的原始数据文件（DTS_raw.csv），其二为沿电缆布设方向获取的带地理坐标的最低与平均温度数据文件（DTS_summary.csv）。本次研究在研究区内的8个测点开展了13次HVSR测量，测量设备为MoHo Tromino TEP-3C型三分量地震仪（MoHo公司，2020年）。HVSR方法需要获取剪切波速（shear-wave velocity）数据以将实测共振频率转换为基岩埋深，而剪切波速取决于沉积物组成与密度（Lane等，2008年）。本次研究通过邻近观测井（美国地质调查局[USGS]站点384428107573901的Poly 7观测井）的HVSR测量结果估算剪切波速，该井配有测井曲线数据（Thomas等，2019年）。“HVSR_saf_files.zip”文件夹中包含SESAME ASCII格式第1版（SAF）的原始HVSR数据，文件记录了垂直分量与2个水平分量（北[N]、东[E]）的三分量时间序列轨迹数据。“Proccessed_HVSR.zip”文件夹中还包含Mast（2020）一文中图12所示的6个测点的处理后HVSR数据，数据格式为PDF。