OVERVIEW / OBJECTIVES

Introduction
The seismology application is divided into 5 sub-sections with overview and objectives listed below (investigators in parentheses). Further details are given in the Seismology sub-sections.

S1. CENS Data Communciations Controller and Network Timing.  The Intel Stargate micro-computer was modified to our application needs. Four working prototypes of the CENS data communications controller (CDCC) box using the Stargate have been constructed and successfully tested.  Parts for 60 have been ordered and a 50 station network is being built. The CENS timing synchronization software has undergone successful tests with the objective the network can operate without access to GPS time, e.g., underground. (Elson, Stubailo, Davis, Estrin, Husker).

S2. Factor Real-time Seismic Monitoring  and Borehole-Strong Motion Array.  During the year the we converted the 72 (USGS) seismometer network in the 17 floor UCLA Factor building to continuous (24 bit) real-time monitoring on the internet. A data base has been set up where channels are recorded at 100 and 500 samples/second on a 1-Tbyte raid array. A paper on Factor was submitted to Engineering Spectra. Factor is now a test- bed for various CENS applications. We received a USGS grant to install a 100 m deep borehole sensor in the UCLA Botanincal Gardens next to the Factor building and 4 ground stations which will expand the test-bed downwards and outwards (Kohler, Davis, Stubailo, Husker, Estrin , Elson).

S3. Broadband Seismic Network - Mexico Experiment. We continue to develop algorithms to model seismic waves and recognized caustics forming in LA basin.  We purchased 50 broadband seismometers that will make up a network controlled by the CENS DCC (see figure). The CDCC is capable of wireless networking from tens of meters to tens of km. We have been invited to join California Institute of Technology and Universidad Nacional Autónoma de México (UNAM )to apply the seismic networking technology to a sesmic array study in Mexico. A proposal was submitted to UCMEXUS.  (Husker, Stubailo, Davis, Elson, Estrin, Harrington, Propst with Clayton from Caltech and Singh, UNAM).

S4. Four Seasons Experiment and Structural Modeling. CENS researchers are collaborating with the NEES researchers on structural analysis and in a shake test of the Four Seasons Building in Sherman Oaks, abuilding that suffered damage in the Northridge earthquake. The shake test experiment involves runing a wireless seismic monitoring array (S5) for structural monitoring alongside the CENS free-field broadband array described in S3.  Structural models of Factor and Four Seasons are being developed to understand building response to earthquakes (Wallace, Taciroglu, Whang, Lei, Skolnik, Elmer). 

S5. Wireless seismic network for Structural Monitoring. A 15-station prototype wireless seismic monitoring array for Factor/Four Seasons has been developed and tested.  It is based on the Crossbow mote technology and will be run side by side with Kinemetrics Q330 digital systems in Factor and Four Seasons for comparison (Ramesh Govindan, Ning Xu, Sumit Rangwala, Krishna Chintalapudi, Deepak Ganesan, Deborah Estrin).