PELENET Update
January 1998
(by Cecily Wolfe)
The PELENET seismic network has been in operation since December 1996 and we expect it will run at least through May 1998.  The network consists of 4 stations installed and maintained by the Department of Terrestrial Magnetism (DTM) at the Carnegie Institution of Washington.  The seismographs are serviced every 3 months to download data and keep the equipment functional.

The goal of the experiment is to use waves from distant ("teleseismic") earthquakes to image upper mantle structure along the Hawaiian swell using various techniques in seismology.  We hope this information will help us understand the geological processes that generate the Hawaiian Island Chain.  The DTM scientific group consists of Cecily Wolfe (now at Woods Hole Oceanographic Institution), Sean Solomon, Paul Silver; and at Northwestern University, Ray Russo and Emile Okal.  The network was installed by Adriana and Randy Kuehnel of DTM.

The network is operated with the generous help of the many kind people and institutions that aided us in siting these instruments.  Below is a description of the station sites:

Station "big2" is located on the island of Hawaii at South Point.  The seismometer and other instrumentation are buried in the ground, with power supplied by solar panels and batteries.

Station "kauh" is on AMFAC Sugar land near Kilohana Crater.  The equipment is buried in the ground, with power supplied by solar panels and batteries.

Station "mauh" is located at the Mees Solar Observatory on top of Haleakala volcano on Maui.

Station "molh" is sited at Molokai Hospital on the island of Molokai.  The seismometer is located in a small closet and is powered by electric power.

All of the above stations perform well.  We are interested in earthquake waveforms in two period bands, periods of 1-2 seconds (for P-waves) and periods of 10-75 seconds (for S-waves and surface waves).  The "kauh" station is the quietest, being sited inland from the ocean (waves generate seismic noise) and away from cultural noise (e.g, automobiles, machinery).  The "mauh" station shows likely wind- and weather-generated noise on top of Haleakala.  The "molh" site is surprisingly good, despite being located near the hospital's air conditioning equipment.  The "big2" site is proving to be much quieter than our first site on the Big Island, which had been much closer to the shoreline and near crashing waves.  Timing for the seismographs is kept in sync by GPS clocks.