## Southern California Seismic Network

## (California Institute of Technlogy (Caltech) and

## United States Geological Survey (U.S.G.S) Pasadena Office)

Date: March 9, 1998

### Location, Contact, and Address:

Southern California Seismic Network recorded at Pasadena, California on the Caltech Campus.

Philip Maechling (phil@gps.caltech.edu) 626 395-3801

1200 E. California Blvd. MS 252-21
Pasadena CA 91125

### Network Characteristics:

Analog Network:

~250 Analog stations with 350 seperate channels and approximately 20 low gain channels.
Analog data are digitized and processed by the Caltech/USGS Seismic Processing System (CUSP) .
This system utilizes VAX hardware and the VMS operating system.

Digital Network:

~55 24-bit digital stations with both 3 component broad-band sensors,
and 3 component strong motion sensors.
~25 19-bit digital instruments with 3 component strong motion sensors.

The number of digital data channels recorded continuously exceeds 500 channels due to the
multiple sensors per site, and the various sampling rates at which our dataloggers generate data.

This network is recorded using a Sun Enterprise 4000 running Solaris 2.5.1

Description of Current Earthworm Usage:

We use the Solaris version of Earthworm for association, location, and earthquake information distribution. We've introduced our own broadband picker, to supply picks to Binder, and our own magnitude program for use with Earthworm. This software runs on our operational real-time seismic monitoring system. It supplies information to the Caltech/USGS staff during Southern California earthquakes.

We also have demonstrated waveform and parametric data distribution from the Caltech/USGS CUSP system over to our digital network processing system using Earthworm messaging techniques. We implemented Earthworm style messages and messaging code on the VAX/VMS system and have been able to distribute data from CUSP to our SUN, running our code on CUSP and regular Earthworm code on the Sun.
Standard EarthWorm Modules in current Use:

Earthworm code (v2.0) running on a SUN Enterprise 4000 under Solaris-2.5.1

- binder -Carl's associator
- eqprelim -rapid reporting of binder associations
- hypomgr, hypoinv -manage and produce standard USGS hypocenter locations
- ring2coax, coax2ring, copystatus, statmgr - (control and monitor)
- ad_demux - This routine converts multiplexed earthworm messages to de-multiplexed Earthworm trace messages.

### Associated programs/modules already developed or adapted here:

- startstop-modified startstop so that it does not require a console.
- rtp-Real-time picker. This phase picker was designed to pick our broadband waveforms. We input these picks to binder.
- eqmag - This modules inputs the hypoinverse results, and calculates a magnitude for the the event. We calculate Ml's from our broadband and strong motion data. By combining eqprelim and eqmag, we generate location and magnitude estimates quite rapidly, frequently in less than one minute after the origin time of a southern California earthquake.
- tpagerfeeder -Our digital processing system used already used some Unix paging software (tpage) and pagerfeeder and tpage were contending for the same phone line. So we modified Earthworms pagerfeeder to use tpage.
- rt2udp - This routine runs on a VAX/VMS CUSP system and distributes earthworm style waveform data. Standard Earthworm coax2ring running on a Sun Solaris computer can then read in the Earthworm packets from CUSP and record our analog data on a Sun computer.

### Development Plans:

- Carl_trig - We are interested in integrating a subnet triggering scheme into our digital processing system. We plan to evaluate the Carl_Trig routine as a basis for the triggering declarations.
- ring2mcast - We are interested in earthworm style data distribution using IP Multicast rather than UDP broadcast. We believe that multicast-based Earthworm data distribution will have efficiency advantages.
- ORB server integration and evaluation - We want evaluate the publicly available version of the JSP/Datascope software. Both the data analysis tools, and the ORB server/client software, are of interest to us.
- WaveServer XX - We have a need for a WaveServer type program. We want to evaluate the latest and greatest WaveServer.
- Upgrade to Recent Earthworm - Our Earthworm system has been stable and hasn't required changes for some time. However, Earthworm development has marched on and it now appears that we are behind the state of the Earthworm art. We expect to upgrade to the most recent Earthworm software sometime during 1998.
- Year2000 Evaluation - We are going to turn our system clocks ahead to the year 2000 and see how Earthworm likes it.

### Our Development Directions:

- WavePool/WaveServer - We believe that a WaveServer type application would provide a valuable way to distribute data after a significant earthquake. We would like to be able to send a data request to a Northern California WaveServer and received waveform data immediately over the internet. And we believe we could offer a service such as that if we can find a robust WaveServer type program.
- Database integration - Both our real-time systems and our data center are moving towards use of commercial databases. We believe that the amount of data that will be generated by the TriNet/SCSN project will require high capacity, robust, data storage only available from commercial databases.
- Integration of Digital and Analog Network Data - We would like to process both our analog network data and our digital network data on the same real-time processing system. We are particularly interested in understanding and learning from the seismic systems which current have this capability such as IceWorm and SunWorm systems.

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