Small Town News

Seismic Monitoring Station installed rural Park River

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EarthScope makes its way to Walsh County

Thursday, Aug. 12, a Seismic Monitoring Station was installed on the Paul and Delaine Peoples farm, rural Park River. It will remain on the Peoples land for two years.

According to Delaine, a team of students from UND came by to assess the area two years ago, as it was the next optimal place on the grid.

Incorporated Research Institutions for Seismology (IRIS) contracted with UND and under the direction of Dr. William D. Gosnold, Professor of Geophysics and Chair of the Department of Geology and Geological Engineering, the students researched and identified possible sites.

This station is just one of hundreds making its way across the United States (west coast to east coast)' as a part of the Transportable Array under the USArray, the seismic component of the EarthScope, a project funded by the National Science Foundation.

The stations are placed roughly 70 km apart in each direction.

The Transportable Array is "leap-frogging across the U.S. over a 10-year period," stated Perle Dorr, Public Outreach Manager of IRIS. "It's been a very fun project to participate in." Out of the 36 Transportable Array stations installed in North Dakota, one will remain behind in Maddock for the duration of the project.

"It's exciting that we have a station going to be left behind in the state," said Fred Anderson, a geologist with the N. D. Geological Survey (NDGS), According to the NDGS, the Maddock facility is one of about 100 broadband seismic monitoring stations scattered across the U.S. that currently make up the USArray Reference Network.

According to IRIS, the Reference Network is composed of permanent stations at roughly 300 km spacing across the U.S. and includes 39 Earth Scope funded permanent stations.

According to Anderson, before the EarthScope project, there were no seismometers in the state and this project is a milestone for North Dakota.

He hopes to be able to collect and analyze the data over the next two years and preserve it for future generations to study as well.

Anderson was on-scene during the installation to observe, learn and report.

Contracted through IRIS, employees of Honeywell Technology Solutions, Inc. handle the installation part of the stations after the constructing portion is finished.

Construction crews prep the area by digging a hole 80-inches down and

approximately 45-inches in diameter.

They proceed to fill the bottom of the hole with one ton of cement to create a vault that they line with rubber liner and reinforce with 42-inch PVC pipe.

A trench is also dug between the vault and the solar panel assembly.

Ken Oliver, Senior Field Engineer, and Charlie Lurton, Electronic Technician, both of Honeywell, were responsible for the set up on the Peoples farm.

According to Lurton, the vault will house a seismometer, a small pump to pump out. any water, a permanent true north and true south mark, a data logger, two batteries, and a vault interface controller.

The interface controller consists of a solar charge controller, a micro-barometer, a thermometer, and a conventional cell phone.

The seismometer is placed at the bottom of the vault and coupled to the ground by 150-pounds of pure, clean sand in a small tube.

The sand also assists in stabilizing the temperature and stopping airflow around the sensor.

The vault is insulated in the middle and on the top with large foam pieces and topped with a reinforced lid that is then covered with 1.5-2-feet of earth to also assist in stabilizing the temperature and stopping airflow.

Approximately twenty feet from the vault is the solar panel assembly. It is a metal pipe that holds the solar panels, a GPS antenna, and a cell phone antenna. A pair of 80-watt solar panels were affixed to the pipe and calibrated to the shortest day of the year for the maximum output of energy. The panels continuously charge the batteries that power the station.

"I took this job to see the United States 42 miles at a time," said Lurton, 62, with a smile. Between Oliver and Lurton, they have installed seismic equipment on all continents and in every ocean on the planet.

"They do a fantastic job of documenting what they do," commented Anderson in regards to the installation of the seismic stations.

The data collected by the seismic sensor will be transmitted via cell phone to the World Wide Web at 40-samples per second, 24-hours a day, 7-days a week.

The information recorded by Transportable Array stations is freely available to anyone worldwide. The public can easily view data from recent earthquakes at any current Transportable Array station via the Web using the USArray Station Monitor at http://usarray.seis.sc.edu.

"If anyone thinks they have experienced an earthquake, call the NDGS," adds Anderson. "That's what we are here for." About Transportable Array According to USArray, http://www.usarray.org, the Transportable Array is a network of 400 high-quality broadband seismographs that are being placed in temporary sites across the conterminous United States from west to east, and Alaska, in a regular grid pattern. With station spacing of about 70 km, Transportable Array data are extremely useful for mapping the

structure of Earth's interior. After a residence time of two years, each instrument is picked up and moved to the next carefully selected location on the eastern edge of the array. When completed, nearly 2000 locations will have been occupied during this program. All Transportable Array systems were acquired with funds provided by the National Science Foundation. In August 2007, the first 400-station footprint was established from north to south along the westernmost quarter of the United States.

Each of the Transportable Array stations consists of a three-component broadband seismometer with associated signal processing, power, and communications equipment. In the early phase of the experiment, significant effort was devoted to the design of the temporary vaults to house the instruments, which resulted in a configuration that provides both high-quality data and a data return of greater than 90%. Data from each station are continuously transmitted to the Array Network Facility at the University of California, San Diego, where initial operational and quality checks are performed, and then sent to the IRIS Data Management Center in Seattle, where all data and associated metadata are archived.

About USArray

USArray is a 15-year program to place a dense network of permanent and portable seismographs across the continental United States. The seismographs record local, regional, and distant

(teleseismic) earthquakes.

USArray consists of four interrelated parts: Transportable Array, Flexible Array, Reference Network, and Magnetotelluric Array. USArray is the seismic component of EarthScope, http://www.earthscope.org, and is a program implemented by IRIS, http://www.iris.edu.



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© 2011 Walsh County Press Park River, North Dakota. All Rights Reserved. This content, including derivations, may not be stored or distributed in any manner, disseminated, published, broadcast, rewritten or reproduced without express, written consent from DAS.

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