## CERI at The University of Memphis, TN

Date: April 14, 1999

### Location, Contact, and Address:

Cooperative New Madrid Seismic Network recorded at University of Memphis, Memphis, TN, and at Saint Louis University, St Louis, MO

Mitch Withers (withers@ceri.memphis.edu) 901-678-4940
Bob Herrmann (rbh@eas.slu.edu) 314-977-3120

3904 Central Ave, Memphis, TN 38152

### Network Characteristics:

84 Analog stations, mostly short-period, three component, covering the New Madrid Seismic Zone in southwest Missouri, eastern Arkansas, and western Tennessee

We are in the process of replacing `eqacquire` with `earthworm`. These two systems are running in parallel at Memphis. We will have at least 3 independent remote processing sites that are able to transfer pick messages via tcp links over ISDN telephone to a central site in Memphis that will then pull waveforms from the wave tanks at the remote sites as appropriate. In addition to the central site at CERI, we currently to have two of the three remote sites operating `earthworm` v3.9.

Analog data are digitized by National Instruments PCI-MIO-16E-4 a2d and we use a single AMUX64T mux (the remote nodes are equipped with dual muxes). We have installed an SMBI backplane to the mux to facilitate wiring, guid, and clock, and to reduce noise. The a2d is installed on a pentium running NT Server 4.0.

11- continuous 16-bit DST (Digital Seismic Telemetry) stations (6 channels each) in Guralp Compressed Format are being folded into the processing. 8 stations are installed.

This web page was stolen from the USGS Menlo Park, and hacked (thanks Lynn).

## Standard Earthworm Modules Currently in Use

### V3.9

### Waveform Data Acquisition & Conversion:

- adsend - digitize waveforms. Production version runs on a Pentium/NT computer, digitizing 64 channels. (remote nodes have 128 channels).
- scream2ew -Listen for Guralp Compressed Format packets broadcast by `SCREAM!`, convert to tbuf, and put on WAVE_RING.
- ringtocoax -broadcast data from the WAVE_RING onto LAN.

  The rest runs on a SUN Ultra-5.

  - coaxtoring -move broadcast waveform data from LAN onto WAVE ring
  - pick_ew -pick P-arrivals from multiplexed data, output to pick ring
  - binder -Carl's associator
  - eqprelim, eqbuf, eqcoda, eqverify -filter, quality check, and output rapid pick associations
  - eqproc, eqbuf, eqcoda, eqverify -filter, quality check, and output final pick associations
  - hypo_mgr, hypoinv -manage and produce standard USGS hypocenter locations
  - carltrig -generate type triglist messages based on Carl Johnson's venerable subnet trigger algorithm.
  - arc2trig -convert hypo arc messages to type triglist.
  - um_report -listens for hyp2000arc messages, then performs a system call to tpage (Tom's free pager software). This is a home-grown module.
  - trig2disk -listens for type triglist messages, queries wave_serverV for data, and writes associated waveforms to disk in ah_xdr format.
  - heli1 -queries wave_serverV every 10 minutes (configurable) to construct psuedo-helicorder gif images of continuous data, and construct associated html documents. Viewable via the CERI seismic networks web server. We're actually running the non-worm version created by Pete Lombard (TYP).
  - export_generic -ships hyp2000arc messages to Golden.
  - import_generic _import USNSN tbuf packets from Golden.
  - various copystatus, etc SOH monitors and restart mechanisms. And certainly something or other that I forgot.

  ### Auxiliary Tasks & Data Exchange:

- wave_serverV - maintain a circular buffer of waveform data and send data from requested channels and time intervals to a client over a socket. Current configuration is about 3 days for 45 channels on an externally mounted FW-SCSI.
- vdl -send triggered waveform data to USNSN

### Programs/modules under development:

- degain -We plan to develop a module that uses a fourth gain channel for each short-period analog station to account for gain-ranged isis instrumentation.
- trig2gif -Create gif images of triggered waveforms on the fly to facilitate remote trigger review under reduced bandwidth connections.

### Our Additional Goals:

- Write better documentation of what we have.
- Reduce reliance on ISDN telephone or otherwise reduce ongoing communications costs.
- Develop non-coda based algorithm to quickly discriminate response level for a given automatically located earthquake.
- PhaseII to complete the loop and make earthworm a complete network processing system and allow RDBMS interface.
- Anxiously look forward to Quanterra to EW so we can incorporate SLU BB network.

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