This issue's Bannergram: The seismograms on the cover and inside pages show vertical component records from broadband PASSCAL instruments at four stations of the MOMA experiment (Missouri to Massachusetts Broadband Seismometer Array; co-PI's: Karen Fischer, Michael Wysession, Tim Clarke). The records are from the Tonga earthquake of April 7, 1995 (depth = 31 km, Mw= 7.5). The goals of the experiment are to constrain the seismic character of the core-mantle boundary, the properties and extent of subducting slabs, and the detailed structure of the upper mantle beneath the eastern United States. The azimuth of propagation from the Tonga earthquake is roughly parallel to the strike of the array. Core phase travel-times, amplitudes and shapes should provide new constraints on the structure of the core-mantle boundary beneath the Pacific Ocean.


Earthworm: A Flexible Approach to Seismic Network Processing. The Earthworm system can be thought of as a toolkit of processing modules for integrating regional seismic network data processing.

IDA Update Happy Anniversary, 20 years of Project IDA. IDA operates 27 stations of the Global Seismographic Network, including six new locations since the last IDA Update in the Fall 1994 IRIS Newsletter.

Robert Casey from the IRIS Data Management Center discusses SOD: An Automated Method for Processing Standing Orders at IRIS DMC, a new automated technique for requesting data from the DMC.

MM12 Pleasant Hill, OH - 99 degrees
Tonga Mw=7.5 - April 7, 1995

Controlling Long Period Air Convection Noise In Borehole Installations With Sand. The Albuquerque Seismological Laboratory studied the high noise levels of Teledyne Geotech KS borehole seismometers. They found that the use of sand reduces noise levels.

IRIS and the Federation of Digital Seismographic Networks (FDSN) are pleased to announce the publication of the first FDSN Station Book. Kris Skjellerup at the IRIS DMC is now taking orders.

The NSF Academic Research Infrastructure Program has funded a proposal, "Hawaii-2 Observatory (H20): a deep-ocean geoscience facility re-using the Hawaii-2 telephone cable."

MM07 Corsica, PA - 103 degrees
Tonga Mw=7.5 - April 7, 1995

IRIS 2000 Submitted to NSF IRIS-2000, a proposal for support of IRIS activities over the next 5 years - was submitted to the National Science Foundation in August. Examples from "Section II can be seen on the IRIS Homepage.

The Seventh Annual IRIS Workshop held in June 1995 at Jackson Lake Lodge, Wyoming was a great success.

Announcing 1996 IRIS Workshop June 19-22, 1996, at the Inn at Semi-ah-moo, near Blaine, WA.

MM01 Florence, MA - 108 degrees
Tonga Mx=7.5 - April 7, 1995


High Resolution Imaging Equipment added to PASSCAL Instrument Pool.

New PASSCAL Datasets Available.

Execom News

Employee News

IRIS Home Page

GSN Update


New Members

The IRIS Newsletter is published quarterly by The IRIS Consortium.
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   The Incorporated Research Institutions for Seismology (IRIS) is a 
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