San Diego Hydrogeology


Mapping the San Diego Formation near Chula Vista, California

Wesley R. Danskin (1) and David L. Schug (2)

Deep monitoring wells have been helpful with mapping the San Diego Formation in the subsurface near Chula Vista, California. In particular, the contact between the lower marine part of the San Diego Formation and the underlying Otay Formation is well defined by changes in lithology and borehole geophysical logs. The contact occurs at the bottom of a coarse-grained basal sand about 10-feet thick, which is coincident with a cool deflection in a geothermal log for a well (SDOT) near San Diego Bay. This contact is exposed in outcrops east of the La Nacion Fault Zone, and occurs at depths of about 500 to 600 feet below land surface west of the fault zone. The inferred vertical offset across the fault zone is about 900 feet.

1) U.S. Geological Survey, San Diego, California
2) URS Corporation, San Diego, California.

Presentation Details

SESSION #42: T45. San Andreas and Walker Lane Neotectonics (Posters)
TYPE OF SESSION: Poster
DATE: Friday, 28 May 2010
SESSION START TIME: 1:30 PM
PRESENTATION START TIME: 1:30 PM
LENGTH: 03:30 (HR:MIN)

FACILITY: Marriott Anaheim Hotel
ROOM: Platinum 5-6
POSTER BOOTH NO: 34

Project Chief: Wes Danskin
Phone: 619-225-6132
Email: wdanskin@usgs.gov


Welcome to the United States Geological Survey (USGS) San Diego Hydrogeology project website, which provides geologic and hydrologic information for the transboundary San Diego–Tijuana area, USA and Mexico. This website provides background information about the project; a variety of news items; a large amount of data, in particular for USGS multiple-depth, monitoring-well sites; geologic and hydrologic models; and additional resources including photos, illustrations, and references. Last updated: April 2016

Some additional data may be available from the USGS database National Water Information System (NWIS).


Questions about San Diego Hydrogeology? Please contact Wes Danskin (email: wdanskin@usgs.gov or send a letter). 619.225.6132