Multichannel seismic-reflection data acquired off the coast of southern California - Part A 1997, 1998, 1999, and 2000

Multichannel seismic-reflection (MCS) data were collected in the California Continental
Borderland as part of southern California Earthquake Hazards Task. Five data acquisition
cruises conducted over a six-year span collected MCS data from offshore Santa Barbara,
California south to the Exclusive Economic Zone boundary with Mexico. The primary mission
was to map late Quaternary deformation as well as identify and characterize fault zones that
have potential to impact high population areas of southern California. To meet its objectives,
the project work focused on the distribution, character, and relative intensity of active
(i.e., Holocene) deformation along the continental shelf and basins adjacent to the most highly
populated areas. In addition, the project examined the Pliocene-Pleistocene record of how
deformation shifted in space and time to help identify actively deforming structures that
may constitute current significant seismic hazards.

The MCS data accessible through this report cover the first four years of survey activity and
include data from offshore Malibu coastal area west of Santa Monica, California to the southern
survey limit offshore San Diego. The MCS data, which were collected with a 250-m-long, 24-channel
streamer used a small gas-injector airgun source. This system provided optimum resolution of
the upper 1 to 2 km of sediment for mapping active fault systems. The report includes trackline
maps showing the location of the data, as well as both digital data files (SEG-Y) and images
of all of the profiles.

For more information on the seismic surveys see http://walrus.wr.usgs.gov/infobank/s/s197sc/html/s-1-97-sc.meta.html , http://walrus.wr.usgs.gov/infobank/o/o199sc/html/o-1-99-sc.meta.html , http://walrus.wr.usgs.gov/infobank/a/a198sc/html/a-1-98-sc.meta.html , and http://walrus.wr.usgs.gov/infobank/a/a100sc/html/a-1-00-sc.seis.html

These data are also available via GeoMapApp (http://www.geomapapp.org/) and Virtual Ocean ( http://www.virtualocean.org/) earth science exploration and visualization applications.

多道地震反射（Multichannel Seismic-Reflection, MCS）数据作为南加州地震灾害任务（Southern California Earthquake Hazards Task）的一部分，采集于加州大陆边缘海域。五次数据采集航次历时六年，采集范围北至美国加州圣巴巴拉近海，南至美墨交界的专属经济区（Exclusive Economic Zone）边界。本次项目的核心使命为绘制晚第四纪变形分布图，并识别、表征可能威胁南加州人口稠密区域的断裂带特性。为达成项目目标，本研究重点针对人口最稠密区域周边的大陆架与盆地，开展活动变形（即全新世（Holocene）变形）的分布、特征及相对强度研究。此外，本研究还分析了上新世（Pliocene）至更新世（Pleistocene）时期变形在时空维度上的演化记录，以助力识别当前可能构成重大地震灾害的活动变形构造。

本报告公开的多道地震反射数据覆盖前四年的勘测工作，采集范围北至加州圣莫尼卡西侧的马里布近海区域，南至本次勘测的南部边界圣迭戈近海。本次采集的多道地震反射数据采用长250米的24道拖缆（streamer）系统，并以小型注气式气枪作为震源。该系统可对1至2千米深的上部沉积层实现最优分辨率，以满足活动断裂系统制图的需求。本报告包含展示数据采集航线的测线图，以及所有地震剖面的SEG-Y格式数字数据文件与成像成果。

如需了解更多地震勘测相关信息，请访问以下链接：http://walrus.wr.usgs.gov/infobank/s/s197sc/html/s-1-97-sc.meta.html、http://walrus.wr.usgs.gov/infobank/o/o199sc/html/o-1-99-sc.meta.html、http://walrus.wr.usgs.gov/infobank/a/a198sc/html/a-1-98-sc.meta.html 及 http://walrus.wr.usgs.gov/infobank/a/a100sc/html/a-1-00-sc.seis.html

本数据集亦可通过GeoMapApp（http://www.geomapapp.org/）与Virtual Ocean（http://www.virtualocean.org/）两款地球科学勘探与可视化应用获取。