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.

本数据集DS 781的此部分提供了加利福尼亚州圣克鲁兹近海制图区地质与地貌图的断层数据。矢量数据文件包含于"Faults_OffshoreSantaCruz.zip"中，可通过http://dx.doi.org/10.5066/F7TM785G获取。

圣克鲁兹近海制图区位于圣安德烈斯断层（San Andreas Fault）西南约15至25千米处，该断层是北美板块与太平洋板块之间分布型转换边界的主导构造。制图区横跨右旋圣克鲁兹断层带，该构造是圣安德烈斯断层系中圣安德烈斯断层西侧的显著构造。圣克鲁兹断层带主要分布于近海区域，全长400千米，南起康塞普西翁角，北至博利纳斯与雷耶斯角（Dickinson等，2005），在制图区内的佩斯卡德罗角以及半月湾以北数千米的柱角等海岸岬角处出露于陆上。

在近海区域，圣克鲁兹断层系形成了宽约2至4千米的分布型剪切带，包含两条主要的分叉断层束。西侧断层束（亦称弗里霍莱斯断层）从佩斯卡德罗角向近海延伸。东侧断层束（亦称海岸道断层或海豹湾断层）在本制图区内大多分布于陆上。据估算，圣克鲁兹断层带的累积侧向滑移速率在该区域约为4至10毫米/年（美国地质调查局（U.S. Geological Survey），2010）。圣克鲁兹断层带的西侧断层束（即弗里霍莱斯断层）构成了圣克鲁兹高地的东部边界。

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）。相关地震反射剖面采集于2007年至2010年间。

引用文献
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. 及 Brabb, E.E., 2005, 加利福尼亚海岸新近纪圣克鲁兹-霍斯格里断层系的右旋净滑移：地质证据与构造意义：《美国地质学会特刊391》，共43页。