High Performance Wireless Research and Education Network

January 24, 2001

HPWREN Provides Seismologists with Improved Seismic Data Collection and Distribution Methods

Today's seismologists can view activity from the earth's interior as it occurs - enabling scientists from around the world to gain extensive insight into the often elusive patterns of seismic waves. However, current seismic research techniques only allow researchers to look at rather broad datasets, which is not always enough information to determine the exact cause and effect of an earthquake.

Frank Vernon, a researcher at SIO's Institute of Geophysics and Planetary Physics (IGPP), is taking real-time data collection and distribution one step farther with the NSF-funded High Performance Wireless Research and Education Network (HPWREN). Vernon, who currently specializes in the development and testing of improved real-time seismic data, recently teamed with Hans-Werner Braun to create, demonstrate, and evaluate the HPWREN, a prototype network that will allow field scientists to send and receive continuous real-time data from remote research stations.

"HPWREN enables researchers like myself and others to collect and distribute datasets that we wouldn't have access to otherwise," Vernon says.

Frank Vernon uses Antelope for his seismic studies

"For example, current monitoring systems do not have enough station coverage for understanding the detailed three-dimensional fault structure of the San Andreas and San Jacinto faults. HPWREN's availability in hard to reach areas provides us with the ability to do more detailed studies of fault zone structure and seismic wave activity, which in turn will provide seismologists around the world with more accurate data."

Concentrating his research on the San Jacinto fault zone, Vernon will use the HPWREN in conjunction with the ANZA Broadband Seismic Network, a 24-bit broadband real-time telemetry network in southern California.

HPWREN Coupled with ANZA Seismic Network Provides Capabilities to Collect Detailed Data

The ANZA Seismic Network is a 15 station, digitally telemetered broadband array that straddles the San Jacinto fault zone from the Buck Ridge fault in the south to the Hot Springs fault at the north end. Equipment consists of Streckeisen STS-2 seismometers with Reftek 24-bit broadband digitizers linked to the central multiplexing and relay site on Toro Peak in the Santa Rosa mountains.

Current ANZA stations are designated by yellow triangles. Sites which have been tested through the ANZA system during temporary deployments, which can be upgraded to permanent sites, are shown by gold triangles. The yellow line shows the microwave telemetry path between Toro Peak and Mt. Soledad near IGPP in La Jolla. Broadband TERRAscope stations are marked by white squares. Seismicity is marked by red circles scaled by magnitude. The Interstate highways are marked in black and dashed red lines are faults of interest.

Vernon and his colleagues at IGPP make their data broadly available, and hence these field stations are representative of research techniques used by seismologists around the world.

Though the use of networks has already assisted seismologists with furthering their research for many years, there is still much room for growth - particularly in the areas of detailed data collection and distribution as mentioned by Vernon.

"The HPWREN project will play a great role in expanding and improving the ways in which seismic research is conducted," Vernon says. "We will soon be able to set up experiments where the number of sensors are an order of magnitude greater than today."

19th Century Scientists Paved the Way for Today's Seismologists

The modern seismometer was invented approximately one hundred years ago, and until the 1980's it was the preferred way to measure seismic activity. One of the earliest seismometers-excluding the ancient Chinese version-was designed by John Milne. Unfortunately, Milne's device could not equal the scope of his proposed studies. A more involved seismometer appeared in the early 1900's, when E. Weichert and B.B. Golicyn developed seismometers that used, respectively, inverted pendulum and electrodynamic sensors that were able to accurately detect the details of seismic waves. This design was improved upon throughout the 20th century, although little was yet known about what was happening at the source of the seismic wave. By the 1980's, simply measuring the amplitude and time of the wave became an obsolete method by which to study earthquakes. This caused the eventual decline of the early seismometer; and with it the emergence of technology sophisticated enough to allow scientists to accurately view the earth's interior. As antiquated as the seismometer of the 19th and early 20th century may now seem, one should note the strides made by early seismologists and the launching point they provided for today's innovations in the field. 1

The HPWREN project is based on work sponsored by the National Science Foundation and its ANIR division under Grant Number ANI-0087344.

Frank Vernon and Hans-Werner Braun

The UC San Diego interdiscplinary project is led by Hans-Werner Braun, a research scientist at the San Diego Supercomputer Center, and Frank Vernon, a geophysicist at the Scripps Institution of Oceanography. The HPWREN includes backbone nodes on the UC San Diego campus and a number of "hard to reach" areas in San Diego county. The HPWREN not only provides high-speed Internet access to field researchers, but also focuses on network analysis research and the provision of educational opportunities for remote communities, such as rural Native American reservations and schools.

For additional information about HPWREN's geophysics applications, please refer to /news/020905.html and /news/011115.html.

-KMB

References:
¹ Duncan Carr Agnew. IASPEI International Handbook of Earthquake and Engineering Seismology. Chapter One: History of Seismology.

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