Marine geophysical data - Point Sal to Refugio State Beach, southern California

This data release includes approximately 1,032 km of marine single-channel seismic-reflection data collected by the U.S. Geological Survey on a research cruise (USGS survey 2014-632-FA) in July and August, 2014, between Point Sal and Refugio State Beach. The dataset includes 168 profiles, most of which were collected on tracklines roughly perpendicular to the coast at 1 km line spacing; additional profiles were collected on coast-parallel tie lines. These data were acquired to support the California Seafloor Mapping Program and USGS Geologic Hazards projects. Seismic-reflection data were collected using a minisparker system that creates an acoustic signal by discharging an electrical pulse between electrodes and a ground that generates a frequency spectrum roughly between 200 and 1,600 Hz. At boat speeds of 4 to 4.5 nm/hour, seismic traces were collected roughly every 1 to 2 meters. Water depths were generally between 50 m and 150 m, but as shallow as 10 meters near the shoreline, and as deep as 480 m for profiles crossing the Santa Barbara basin. Acoustic pulses were generated at 0.5-second intervals on most profiles; a 1-second interval was used on the few profiles collected in deeper water. Standard SEG-Y files were generated using a Triton Subbottom Logger (SBL). Seismic data processing was accomplished using Sioseis, a public-domain software developed at Scripps Institute of Oceanography (part of the University of California at San Diego). The processing of these data consisted of a bandpass filter, mute function, automatic gain control, water bottom detect, swell correction, and scaling/plotting. Both raw data in SEG-Y format and processed data (Corrected SEG-Y) are provided in this data release.

本次发布的数据集包含约1032千米的海洋单道地震反射数据，由美国地质调查局（U.S. Geological Survey）于2014年7月至8月在萨尔角（Point Sal）与雷富吉奥州立海滩（Refugio State Beach）之间的科考航次（USGS调查编号2014-632-FA）中采集。该数据集共包含168条测线剖面，其中大部分沿与海岸大致垂直的方向布设，测线间距为1千米；另有少量剖面沿海岸平行方向布设作为联络测线（tie lines）。本次数据采集旨在支撑加州海底制图项目（California Seafloor Mapping Program）与美国地质调查局地质灾害研究项目。
地震反射数据采用小火花震源（minisparker system）采集，该系统通过在电极与接地极之间释放电脉冲产生声信号，其频谱范围大致介于200~1600赫兹之间。当航速维持在4~4.5节时，每1~2米采集一道地震数据。作业海域水深普遍介于50~150米，近岸区域水深可浅至10米，横穿圣巴巴拉盆地（Santa Barbara basin）的测线剖面最大水深可达480米。大部分测线剖面的声脉冲发射间隔为0.5秒；在深水区域布设的少量测线剖面则采用1秒的发射间隔。
标准SEG-Y格式数据文件通过Triton Subbottom Logger（SBL）生成。地震数据处理采用斯克里普斯海洋研究所（Scripps Institute of Oceanography，隶属于加州大学圣迭戈分校）开发的公有领域软件Sioseis完成。本次数据处理流程包括带通滤波、切除处理、自动增益控制、水底识别、涌浪校正以及刻度缩放与成图。本次数据发布同时提供SEG-Y格式原始数据与处理后的校正SEG-Y（Corrected SEG-Y）格式数据。