Faults--Offshore Santa Cruz, California

This part of DS 781 presents data for the faults for the geologic and geomorphic map of the Offshore Santa Cruz map area, California. The vector data file is included in "Faults_OffshoreSantaCruz.zip," which is accessible from http://dx.doi.org/10.5066/F7TM785G. The offshore Santa Cruz map area lies about 15 to 25 km southwest of the San Andreas Fault, the dominant structure in the distributed transform boundary between the North American and Pacific plates. The map area straddles the right-lateral Santa Cruz Fault zone, a prominent structure west of the San Andreas Fault in the broader San Andreas Fault system. The Santa Cruz Fault zone occurs predominantly in the offshore and extends 400 km from Point Conception on the south to Bolinas and Point Reyes on the north (Dickinson and others, 2005), coming onland at coastal promontories such as Pescadero Point in the map area and Pillar Point, a few km north of Half Moon Bay. In the offshore, the Santa Cruz Fault system forms a distributed shear zone about 2 to 4 km wide that includes two main diverging fault strands. The western strand (also known as the Frijoles Fault) extends offshore from Pescadero Point. The eastern strand (also known as the Coastways Fault or Seal Cove Fault), is mostly onshore in this map area. Cumulative lateral slip on the Santa Cruz Fault zone is thought to range from 4 to 10 mm/yr in this region (U.S. Geological Survey, 2010). The western strand of the Santa Cruz Fault zone (i.e., Frijoles Fault) forms the eastern boundary of the Santa Cruz high. Faults were primarily mapped by interpretation of seismic reflection profile data (see OFR 2013-1071). The seismic reflection profiles were collected between 2007 and 2010. References Cited Dickinson, W.R., Ducea, M., Rosenberg, L.I., Greene, H.G., Graham, S.A., Clark, J.C., Weber, G.E., Kidder, S., Ernst, W.G., and Brabb, E.E., 2005, Net dextral slip, Neogene Santa Cruz-Hosgri fault zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p.本DS 781数据集的本章节提供了美国加利福尼亚州近海圣克鲁斯（Offshore Santa Cruz）制图区域地质与地貌图对应的断层相关数据。矢量数据文件存储于"Faults_OffshoreSantaCruz.zip"压缩包内，可通过链接http://dx.doi.org/10.5066/F7TM785G获取。 该近海圣克鲁斯制图区域坐落于北美板块与太平洋板块间离散转换边界的主控构造——圣安德烈亚斯断层（San Andreas Fault）西南侧约15至25公里处。制图区域横跨右旋圣克鲁斯断层带，该断层带为广义圣安德烈亚斯断层体系中圣安德烈亚斯断层西侧的显著构造。圣克鲁斯断层带主体分布于近海海域，整体延伸达400公里，南起康塞普西翁角（Point Conception），北至博利纳斯（Bolinas）与雷耶斯角（Point Reyes）（Dickinson等，2005），并在制图区域内的佩斯卡德罗角（Pescadero Point）及半月湾以北数公里的柱石角（Pillar Point）等海岸岬角处出露陆域。 在近海海域，圣克鲁斯断层体系形成了宽度介于2至4公里的离散剪切带，包含两条主要的分支断层。西侧分支（亦称弗里霍莱斯断层（Frijoles Fault））自佩斯卡德罗角向近海延伸。东侧分支（亦称海岸断层（Coastways Fault）或海豹湾断层（Seal Cove Fault））在本制图区域内主要分布于陆地区域。据估算，该区域圣克鲁斯断层带的累计侧向滑移速率介于4至10毫米/年之间（美国地质调查局（U.S. Geological Survey），2010）。圣克鲁斯断层带的西侧分支（即弗里霍莱斯断层）构成了圣克鲁斯隆起的东部边界。 本次断层制图主要通过解译地震反射剖面（seismic reflection profile）数据完成（详见OFR 2013-1071）。相关地震反射剖面数据采集于2007年至2010年间。 参考文献 Dickinson, W.R.、Ducea, M.、Rosenberg, L.I.、Greene, H.G.、Graham, S.A.、Clark, J.C.、Weber, G.E.、Kidder, S.、Ernst, W.G. 与 Brabb, E.E.，2005年，《加利福尼亚沿海新近纪圣克鲁斯-霍斯格里断层带的净右旋滑移：地质证据与构造意义》：美国地质学会（Geological Society of America）专刊（Special Paper）391，共43页。