SCEC Borehole Initiative Workshop

DATE: 25 March 1997

TIME: 9-4:30 pm

LOCATION: Davidson Conference Center, USC

Click here for the Schedule, or scroll down.

BACKGROUND:

As part of its 5 year renewal proposal to NSF and USGS in 1996, SCEC proposed to "drill and instrument three boreholes per year from 1997 to 1999. Each borehole will be drilled and cased to a depth of 100 m in rock and be logged for P- and S-wave velocity and density. A three-component force-balanced accelerometer (FBA) with 120 dB dynamic range will be grouted in place at the bottom of each hole. A second FBA will be placed at the surface. A six-channel Kinemetrics K2 data acquisition system (which includes the surface FBA) with dial-up capability will digitize the data, store it on site and telemeter the data into the SCSN. This arrangement will allow on scale recording for M>2.5 to be recorded with good signal to noise at distances of at least 40 km and perhaps as far as 70 km. All data will be incorporated into the SCSN. The data will complement on-going strong motion arrays in southern California.

"Drilling each of 3 holes to a depth of 100 m (4 7/8"), casing with 4" PVC, logging for P and S velocity and density, and installation of the downhole sensors...."

These proposed borehole installations "will help in reducing the uncertainty in predicting ground motion from future earthquakes."

During the review process, it was suggested that SCEC hold a workshop to review the scientific objectives and better define the need for borehole instrumentation versus other scenarios, such as surface arrays, before preceding with the installation. This workshop will address those concerns. The SCEC board has asked that this workshop include discussion of a proposal submitted by several SCEC investigators (including Quinn, Yeats, and Ponti) to drill a deep borehole in the Hollywood area to look at Quaternary slip rates on the Santa Monica fault and Wilshire Thrust.

This workshop will be hosted by Ralph Archuleta, Jamie Steidl, and Dave Jackson and is planned for one day, March 25, 1997. It will be held in Los Angeles as it is easier for participants traveling by air. While this workshop is open to all SCEC scientists, there are several invited speakers and participants that need to be present and if this date is not acceptable to most, it may be rescheduled. Invited speakers will be contacted by Ralph and Jamie in the very near future after the date is confirmed. Travel funds are available for participants in this workshop.

SCHEDULE:

The workshop will begin by reviewing the existing/planned surface and borehole instrumentation in the Los Angeles area, and then discuss the scientific justification for borehole data. The workshop will then discuss possible borehole instrumentation scenarios, as well as alternatives to borehole instrumentation. There will leave a block of time in the afternoon for any participant to make a brief presentation.

8:15am Continental Breakfast

I. Introduction

9:00am Dave Jackson-(SCEC/UCLA)

II. Review of Existing/Planned Surface and Borehole Data & Instrumentation.

9:10am Bob Nigbor-(Agbabian Associates)
ROSRINE project

9:20am Dave Boore-(USGS)
USGS borehole data

9:30am TBA-(CDMG/Caltrans)
Future plans for CDMG instrumentation

9:40am Ralph Archuleta-(UCSB)
UC campus instrumentation

9:50am Egill Hauksson-(Caltech)
Tri-net instrumentation

10:00am Discussion

10:20am Coffee Break

III. Scientific justification for borehole instrumentation.

10:40am Tom McEvilly-(UCB/LLBL)/Larry Hutchings-(LLNL)
Bay area borehole network

10:55am Ralph Archuleta-(UCSB)
Looking at details of the earthquake source

11:10am Kim Olsen-(UCSB)
Theoretical modeling using borehole data

11:25am Jamie Steidl-(UCSB)
Ground motion prediction and non-linear effects

11:40am Discussion

12:00-1:00pm Lunch Break

IV. Possible Borehole Scenarios and Alternatives

1:00pm Dan Ponti-(USGS)

1:10pm Questions/Discussion

1:20pm Ralph Archuleta/Jamie Steidl-(UCSB)

1:30pm Questions/Discussion

1:40pm Jim Mori-(USGS)

2:00pm Questions/Discussion

2:20pm Coffee Break

V. Open Floor Discussion

2:40-4:30pm

Workshop Ends 4:30pm