RAC Meeting September 2002

Date: September 25, 2002

University of Washington, PNSN labs

 

Chair: CB Crouse, URS

 

Scott Shimel, UW Seattle Mapping Project

Bill Perkins, Shannon & Wilson

Steve Palmer, DNR

Dave Nelson, Washington Emergency Management Division

George Thomas, PNSN

Craig Weaver, USGS

Steve Malone, PNSN

Marc Eberhard, UW Civil Engineering

Ginny Thompson, Bank of America Emergency Management

Bill Steele, PNSN, facilitator

 

Paul Grant (for a short while)

 

 

Steve M and CB Crouse reviewed sections of the NIC meeting relevant to PNW Advisory Committee issues. The NIC meeting primarily addressed policy issues and the production of guidance for next year's regional planning effort. Discussions of structural monitoring at the NIC meeting generate quite a bit of interest. While the original ANSS plan called for a 50/50 ratio of free field and structural sites there were regions (PNW and Northeast in particular) who felt that it was too early with too little funding to try and obtain that ratio. What we learned from the Nisqually earthquake was that we now need a greater portion of free field sites. Monitoring structures requires greater resources. In a situation with funding constraints one must choose between few structures or many free fields. Until we are at a higher level of funding we should stay on the present course of mostly installing free field sites. It might make more sense to put limited resources into monitoring structures in CA rather than the PNW, since these structures experience a higher seismicity rate and would likely provide a richer database. Also, while a portable array for ambient monitoring is still of interest to some in the PNW, the NIC and others feel that it should be done from funding sources other than ANSS, such as NEES.

 

The question was raised as to who has looked at the data from structures with recordings of the Nisqually earthquake. Known structures are the DNR building in Olympia, Tacoma General Hospital and the Crown Plaza in Seattle. There was some confusion about the quality and even location of the data. NSMP has DNR data, UW (George Thomas) has Tacoma General Hospital data but in a strange format. An engineering course at UW may try to use data from one of these structures but there were questions about the number of records available for fairly complex buildings. Several comments were made about the usefulness of the free field data in the weeks after Nisqually and that making those data quickly and easily available for future events was a high priority.

 

A discussion of down hole monitoring came up because of continuing problems understanding non-linear responses of soils during the Nisqually event. The committee encouraged ANSS to look into the possibilility of taking advantage of new or existing holes for such monitoring. (See later section on plans for next year). There were also questions regarding pore pressure sensors being funded by the ANSS. Since they are not specifically mentioned as part of the ANSS program their purchase and installation probably could not be funded by ANSS; however, it probably would be possible to have their data coordinated and possibly recorded along with ANSS data.

 

 

After being in operation for two years it is time to start changing and rotating membership of the Advisory Committee and its subcommittees. Stephen Weiser and Mike Gallagher will rotate off of the Advisory Committee to be replaced by Bill Perkins and Susan Chang. Steve Malone was directed to contact John Beaulieu to get DOGAMI participation in the Advisory Committee. The lack of participation by any Oregon group, even by telephone for this meeting was seen as a big disadvantage.

 

Because of the importance of positioning ourselves to do structural monitoring in the future in an efficient way, a structures subcommittee was formed to be headed by John Hooper. CB Crouse will work with John to populate the committee with appropriate members. Several suggestions were made for asking individuals to be members.

 

Because of too many other responsibilities Paul Grant will step down as chair of the siting subcommittee but remain a member. Bill Perkins or Susan Chang will chair the committee. Steve Palmer volunteered to remain a member of this committee. Craig recommended that there be a member of Seattle DOT, DOGAMI, or BPA on the committee. A member of the Seattle Mapping Project should be on this committee. S. Malone recommended that someone from Art Frankel's group participate on the committee. The importance and urgency of this subcommittee's work is increased and thus a meeting of this subcommittee in the near future is a must. See below.

 

(subcommittee members will be added when available)

 

 

George Thomas reviewed recent installations: Three strong-motion stations, EYES, COLT and HUBA were installed in the greater Portland area in the past two weeks. These are essentially free field sites. SHIP (Seattle Ship Canal Bridge) had a continuous telemetry system installed along with the current dial-up NSMP instrument. Both instruments will operate at the same site for some overlap period. This is the first test of a of wireless-IP telemetry system in the PNW. Two new stations were installed in the Puget Sound region; SVTR is at a school in North Bend within a few km of ELW but on different geology, and MEAN is on Capital Hill in Seattle.

 

Other accomplishments are the hardening of existing free field sites with improved back-up power systems. This power system resolved an ongoing RFI problem at Camp Murray. Camp Murray has been taken over as a NSMP dial-up site because of the impossibility of getting easy continuous telemetry from it.

 

Information products development has proceeded very slowly. ShakeMap is still not automated and delivery of it other than via WEB pages has not been developed. Training in its use is of interest to EMD, but none is available yet.

 

 

The importance of having site characterization information at strong-motion sites was discussed at length. Steve Palmer has a FEMA sponsored project for characterizing 10 sites via bore-holes of which three are to be in eastern WA and seven in western WA. Bore-holes will be about 30 to 50 meters deep. He will collect disturbed samples but can also do undisturbed samples if there is interest. He also plans to do standard Vp & Vs measurements at up to 100 other sites to try and get a good estimate of shallow velocities in all major soil types found in Washington. Steve still needs to identify 20 potential sites to finish his drilling proposal and is seeking advice from the ANSS siting committee. He could start the project within a few months and the project duration is 1.5-2 years.

 

Craig Weaver reported that a NEHRP external proposal has been funded to do shallow velocity surveys of about 30 sites in the Puget Sound area. This is independent of Steve Palmer's work but the committee hopes that there will be good coordination between these two groups.

 

 

A formal ANSS PNW Regional plan for the coming year is due at the end of October. Steve Malone presented a tentative plan (partially based on previous discussions with the committee) for discussion and approval. The committee discussed and approved the following recommendations regarding siting for next year:

 

Re-occupation of abandoned sites that recorded the '49 and '65 events. There is a nice report on these stations that Steve P will share with Steve M. These sites include

Highway Test Lab (in Olympia?)

Highway Test Lab (in Seattle?)

Federal Building, Seattle

a building in Tacoma

a building in Portland

 

(NOTE: After the meeting Ron Porcella of the NSMP apologized for missing the meeting conference call due to illness and supplied some useful information about the instruments recording previous earthquakes. See end of this report.)

 

Re-occupation of some sites abandoned by Art Frankel (to be chosen by the siting committee with Art's help).

 

An array of instruments (~12) in the south Seattle/Duwamish area. Because of difficult telemetry in this area these could likely need wireless telemetry. Radical Software has a proposal for engineering such a system. This may be an ideal project to solicit cooperation with others (see below).

 

Development of a meta-database for site characterization. This information is as critical as seismograms. Since DNR and a NEHRP contract will do the work, making sure that the results are well coordinated with the strong-motion data should be an ANSS responsibility.

 

Continued installation of free-field/reference stations in Urban centers of Washington and Oregon should continue. Suggestions included several more in north-western Oregon using their school network (which seems to be working very well with the new stations just installed there this past month). Several in the greater Puget Sound area and also one in Yakima (near most active Recent mapped fault in the State).

 

 

Current cooperating agencies are the following:

BPA - sites and telemetry (lots)

DOGAMI - purchase of strong-motion instruments (3 thus far but more in future)

Portland Water - Purchase and installation of instrument (but telemetry is not yet going).

 

Craig has been in talks with Seattle DOT. They have funding for instrumentation and are interested in free field recordings at a number of bridge sites including:

West Seattle Bridge and Spokane St. viaduct

15th Ave bridge over Matthew's Creek at 125th St.

Interbay bridge

Ballard Bridge

Fremont Bridge

 

Discussion of this interest brought up the possibility of combining the proposed south Seattle/Duwamish array with monitoring of the West Seattle and Spokane Street bridges. Also, the site characterization bore-holes which Steve Palmer does could possibly be used for down-hole monitoring as part of this combined system too. If Seattle DOT can fund some instruments and ANSS does some instruments and the telemetry and recording the combination could be much greater than the parts. On-going operation and information products delivery to Seattle DOT (and other departments) should be considered at the same time.

 

Marc Eberhard reported on a preliminary proposal he has put in to Wash DOT for an improved ShakeMap and information products which would include bridge fragility information convolved with measured and inferred shaking values to estimate damage potential at many bridges.

Craig also reported on continuing discussions with the Military and Department of Justice regarding the usefulness of ANSS for rapid response, hazard mitigation and information.

 

 

The siting subcommittee should be formed and meet soon to help identify sites for the Duwamish Array project and for Steve Palmer's characterization project.

 

The structures subcommittee should be formed and quickly review and finalize the identification of important structures in the area that should have, at least reference station near them and perhaps also for structural monitoring when ANSS funding reaches a higher level. This committee will ned some coordination with the siting committee for the reference station distribution.

 

Initial members of both the siting and structures subcommittees should be sent to Steve Malone within a week or so.

 

The next general Advisory committee meeting is tentatively scheduled for Jan. 15.

 

 

Regarding the proposal to re-occupy the '49 and '65 NSMP accelerograph sites-- there were just two strong-motion sites that recorded the '49 event-the Highway Test Lab on State Ave in Olympia (epicentral dist = 16 km), and the Seattle Army Base (dist. = 60 km); both stations were established in October 1948.

 

The Olympia station is a freefield site, which was recently moved from the original 6' by 8' wood/metal storage shed to an adjacent 4 sq/ft fiberglass t-hut; it is currently instrumented with a K2. We've had some difficulty establishing telephone service (trenching expense) to this location, but are still working on it.

 

The second site was the ACOE Meteorological Station on the Seattle Army Base, at 4735 East Marginal Way. The instrument was in a small (8' by 10') wood-framed shed. The recording station was closed and the accelerograph was moved to the Seattle Federal Office Bldg in June 1953 (does the Seattle Army Base still exist?)

 

The '65 event was recorded at 5 NSMP stations: 1) on the ground floor of the 11-story, reinforced concrete State Office Bldg in Portland; 2) the crest station on the concrete Ross Dam; 3) in the sub-basement of the 9-story, steel-frame Federal Office Bldg in Seattle; 4) in the basement of the 10-story, concrete and steel County-City Bldg in Tacoma; and 5), at the Highway Test Lab in Olympia.

 

As I mentioned, the Olympia station still exists. The accelerograph at the State Office bldg in Portland was relocated in 1970. Seattle City Light recently took over responsibility for maintaining instrumentation at Ross Dam (which I understand was recently upgraded to Etna's, no comm.). And both the old Federal Office bldg in Seattle and the Tacoma County-City Bldg were on the list of structures recommended by the USGS Puget Sound Region Instrumentation Advisory Committee (Bruce Olsen, Chair), as priority candidates for extensive new seismic instrumentation (see USGS Open-File Report 89-374)