Raw data of vibroseismic measurements on Thwaites Glacier, Antarctica from 2022/23

This vibroseismic survey was conducted on Thwaites Glacier in West Antarctica in 2022/23, as part of the International Thwaites Glacier Collaboration's project GHOST (Geophysical Habitat of Subglacial Thwaites). The 210 km long seismic profile (section 20230551) was measured parallel to the average flow direction. The seismic source was generated by a seismic vibrator "EnviroVibe" (Industrial Vehicles Inc.) that was placed on a polyethylene sled and towed by a snow tractor (Eisen et al., 2015). The seismic vibrator was operated at 60% peak force (40 kN) with a shot interval of 75 m. At every shot location, we performed two sweeps. The first sweep (setup sweep) was used for snow densification and not recorded while the second sweep (acquisition sweep) was recorded with a 1500 m long "snowstreamer" (Fjord Instruments) towed behind the seismic vibrator. The sweep had a frequency range of 10–250 Hz. The up-sweep length was 10 s, with 0.5 s tapering at begin and end. The snowstreamer consists of 60 channels with a 25 m group spacing and a minimum offset of 43 m. The eight gimballed p-wave geophones per channel recorded for 14 s at a sampling interval of 0.5 ms. The signal was recorded with 3 "Geodes" (Geometrics Inc). GNSS data at every shot location were recorded with a Novatel Flexpak via a GNSS antenna located on the roof of the seismic vibrator. With this set-up, we collected ten-fold data in the upstream direction. The seismic raw data were processed to the different levels with Paradigm Echos (Aspen Technology Inc.).This dataset contains the recorded raw vibroseismic data in standard SEG-Y format, compressed by a cross-correlation with a synthetic source signal. The individual traces were assigned idealized geometry of shot locations. The shot coordinates include surface elevation relative to WGS84 based on ice surface heights.

本振动地震勘测于2022/2023年在西南极洲思韦茨冰川（Thwaites Glacier）开展，隶属于国际思韦茨冰川合作计划（International Thwaites Glacier Collaboration）的GHOST（冰下思韦茨冰川地球物理栖息地，Geophysical Habitat of Subglacial Thwaites）项目。本次勘测所获取的210 km长地震剖面（编号20230551）沿冰川平均流向布设。地震震源由工业车辆公司（Industrial Vehicles Inc.）生产的"EnviroVibe"型振动震源车提供，该震源车搭载于聚乙烯雪橇之上，由雪地牵引车拖曳作业（Eisen等，2015）。本次振动震源车以峰值力的60%（40 kN）运行，放炮间隔设为75 m。每个放炮点位均完成两次扫描脉冲：第一次为设置扫描（setup sweep），仅用于积雪压实，未进行数据记录；第二次为采集扫描（acquisition sweep），由布置在振动震源车后方的1500 m长"雪下拖缆"（snowstreamer，峡湾仪器公司Fjord Instruments生产）完成数据采集。本次扫描脉冲的频率范围为10–250 Hz，上行扫描时长为10 s，起始与结束阶段均施加0.5 s的渐弱处理。该雪下拖缆共包含60道接收通道，道间距为25 m，最小偏移距为43 m。每通道配置8个万向纵波检波器，采集时长为14 s，采样间隔为0.5 ms。地震信号通过3台Geometrics公司生产的"Geodes"型设备进行记录。每个放炮点位的GNSS数据由搭载于振动震源车车顶的GNSS天线通过Novatel Flexpak设备采集。通过该观测系统，我们获取了顺流方向的十倍覆盖地震数据。原始地震数据通过Aspen科技公司（Aspen Technology Inc.）的Paradigm Echos软件完成多层级处理。本数据集包含以标准SEG-Y格式存储的原始振动地震数据，数据已通过与合成震源信号的互相关实现压缩。各单道数据均赋予放炮点位的理想化几何布局信息。放炮坐标包含基于冰面高程获取的、相对于WGS84（世界大地测量系统1984）的地表高程值。