SCEC 2010 Annual Report- PBIC

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2010 SCEC Annual Report: SCEC Portable Broadband Instrument Center PI: Jamison H. Steidl Earth Research Institute, University of California, Santa Barbara

Background: The PBIC was established in 1991 by Prof. Ralph Archuleta through funding from SCEC

to provide a "pool" of digital seismic recording equipment for use in post earthquake response and on individual PI driven research experiments within southern California. The PBIC is currently managed at the Earth Research Institute (ERI) by Dr. Jamison Steidl with support from undergraduate student laboratory assistants from the department of geological sciences and electrical and computer engineering.

The ability for SCEC to respond rapidly to a major southern California earthquake with the deployment of seismographs in the near-source region was a catalyst for the creation of the PBIC and is a critical asset of SCEC earthquake research community. This has been highlighted recently by the successful deployment of PBIC equipment in the 2010 El Mayor–Cucapah earthquake as well as the 2008 shakeout experiments along the southern San Andreas. Other PBIC successful RAMP deployments occurred in conjunction with the 2004 Parkfield and 2003 San Simeon earthquakes, as well as the four major earthquake sequences in the previous decade (1992 M6.1 Joshua Tree and M7.3 Landers, 1994 M6.7 Northridge, and 1999 M7.1 Hector Mine). The ability to conduct individual PI driven research experiments in between these major earthquake sequences using PBIC equipment is another very important asset. One of the main goals of the PBIC is to facilitate research in the earthquake community by providing readily accessible seismic monitoring stations for deployment in the southern California region.

The current data recorders maintained by the PBIC are primarily Refraction Technology (RefTek) 16- and 24-bit data loggers that record to 1 Gb SCSI hard drives (or larger) in field enclosures. Sensors consist of high output velocity transducers to record weak motion and force balance accelerometers designed to stay on-scale (up to +/- 2G) for the strong ground motion expected from very large earthquakes. A broad dynamic range of recording is obtained by pairing both types of sensors with a single 6-channel recorder. The PBIC also operates intermediate period sensors that provide increased frequency bandwidth to allow better investigation of deep basins and crustal structure from regional and global seismicity.

In addition to these older style stand-alone stations, two newer stations with real-time telemetry capabilities are also now part of the PBIC inventory. These consist of Kinemetrics Q330 6-channel 24-bit data loggers and 8Gb Marmot field processors. Real-time data communications is typically handled via VPN broadband cellular modem technology that has the capability of streaming 6 channels of data at 200 samples per second. Two new Kinemetrics FBA ES-T (Episensors) tri-axial accelerometers are also available for deployment with these data acquisition systems, as well as the traditional L4C-3D three-component weak motion PBIC sensors.

2010 PBIC Highlights

Acquisition of DOE equipment to augment the current PBIC equipment pool In late 2009, DOE representatives informed UCSB that they would be making RefTek 72A

equipment available via the Energy-Related Laboratory Equipment (ERLE) grant program. UCSB completed the application in early 2010 and a pallet of equipment was eventually

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delivered to UCSB that contained RefTek data acquisition systems (DAS) similar to what the PBIC already maintains in its current inventory. While some of this equipment was not functional, many of the systems are currently running in the lab at UCSB and are working well. These additional DAS’s will; help ensure that the PBIC has working equipment when the next “Big One” strikes. This equipment will provide spare parts no longer available through RefTek who has stopped supporting the 72A series, and enable the PBIC to continue to support the instruments until an equipment upgrade proposal is funded, hopefully through SCEC4. The cost for this equipment was just the price of shipping the pallet from Nevada to UCSB.

Deployment of PBIC stations during the El-Mayor Cucapah earthquake RAMP Immediately following the El-Mayor Cucapah earthquake the PBIC began prepping

stations for deployment. The L4C weak motion sensors were deployed on a UC Riverside project at the time of the earthquake, and these were retrieved by the UCR group and re-deployed with newer UCR RT130 dataloggers along the northern end of the rupture zone. In addition, the two PBIC Q330/Marmot stations were deployed in continuous mode, and one of the older RefTek 72A systems in triggered mode in the same region. All of this effort was done in collaboration with the USGS strong motion program that was deploying K2 dataloggers in the same region just north of the border (Figure 1).

Figure 1. El-Mayor Cucapah RAMP deployment. UCR/PBIC sites (blue), UCSB/PBIC sites (brown), USGS K2 sites (green) and aftershock activity overlain a Google Earth image.

Deployment of PBIC real-time stations along the Elsinore Fault zone UCSB/PBIC stations deployed during the El-Mayor Cucapah RAMP were picked up after

only 30 days due to security concerns at the sites where the stations were located, and temperature concerns for the older RefTek 72A system that was using a conventional hard disk. An increase in the aftershock activity in early June following an M5.7 event at the northern end of the mainshock rupture zone prompted another deployment of the two real-time PBIC stations. The first station was deployed at a secure location north-east of Ocotillo, at a private residence, and connected to Caltech/USGS via cellular modem (Station ZY_COON). The second station

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was deployed at a site in Mesa Grande (ZY_MGD) along the Elsinore fault about 90km north-west of the COON site, and connected to the internet through collaboration with the Pala Indian Reservation’s tribal digital network (TDVNet) and the UCSD NSF supported High Performance Wireless Research and Education Network (HPWREN). These stations were selected after consultation with Caltech/USGS in order to increase the station density of the regional network along the Elsinore fault zone. These sites can also be seen in Figure 1.

The two real-time PBIC stations will remain deployed along the Elsinore fault until another project requests them, or the current active rate of seismicity in the region subsides. These stations are continuously providing data to the network, and being used in both earthquake locations and Shake Map applications. The M4.6 earthquake on November 4th, 2010 at the northern-end of the El-Mayor Cucapah is an excellent example of the PBIC stations contributing to these applications through real-time data transmission.

Figure 2. PBIC stations contributing to earthquake locations and Shake Map.

Both station MGD and COON show up on the Shake Map that was created following this earthquake. The COON station was located 13km from this event, only one other station was closer. The COON station is often one of the closest stations to the events that are occurring in this region due to its location right on top of the northern end of the El-Mayor Cucapah aftershock activity. Peak ground motions from this recent M4.6 event were above 10%g at the COON station. The combination of the short-period weak-motion L4C sensor with the strong motion FBA ES-T sensor, both connected to the 24-bit Q330 datalogger, are proving useful to the network in locating events as small as M1.0, and still capable of being on-scale to +/-2g.

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Figure 3. PBIC real-time station COON providing data for the ShakeMap application.

Maintenance of PBIC Equipment As usual, 2010 PBIC activities included the maintenance of all the systems that are now

part of the PBIC inventory of equipment, including the SCEC, DOE, and long-term loan IRIS/PASSCAL equipment. Maintaining a pool of working stations for rapid deployment in the event of a significant earthquake in California remains the first priority of the PBIC. One geology and two geophysics undergraduate majors, and one electrical and computer engineering major currently work in the PBIC lab assisting with the maintenance of the equipment. We now keep a rotating pool of at least 10 stations in the lab, under power and in acquisition mode, on a 24/7 basis. This is in addition to the two projects (12 stations) that are actively deployed.

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Broader Impact: The educational impact of the PBIC is demonstrated by the number of undergraduate and

graduate student participants in field deployments (Figure 4), and in the routine maintenance and operations of the PBIC. Most experiments use undergraduate and graduate students in the deployment and maintenance of the stations, many at UCSB, but also at other institutions within California. Giving the students hands-on experience in how the data is collected is an important part of the education of future geophysicists, especially in a time when data is so readily available via the Internet without any knowledge of what is involved in the data collection process. In addition, the number of women and minority students previously and currently involved in the PBIC program is significant. Outreach to K-12 students has always been an important part of the PBIC program, with the “make your own earthquake” demonstration being a hit year after year with all K-12 age groups.

Figure 4. UCSB and UCR students complete the installation of a PBIC station OYSB following the El-Mayor Cucapah earthquake.