University of Hawai'i
(808) 956-8856 Telephone
For Immediate Release:
October 19, 1999
Contact: Milton Garces (808) 331-1401
|Comprehensive Nuclear-Test-Ban Treaty monitoring station
to be installed in Kona|
The University of Hawai'i plans to install a facility in Kona for monitoring distant nuclear explosions. This facility will consist of an infrasound array and a laboratory. The Hawai'i array will be an integral part of the 321-station International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The facility has important repercussions for national and international security, and may be utilized for the monitoring of local hazards such as storms, volcanic eruptions and meteorites. In addition, the facility will initiate a new field of research in Hawai'i, and provide new employment and educational opportunities.
"The aim of the CTBT is to encourage nuclear disarmament and promote global collaboration. In addition, the IMS will provide the first truly global, fully integrated geophysical monitoring network, and will use some of the best technology available," says Dr. Milton Garces, principal investigator, who is a resident of Kona.
Infrasonic waves are pressure disturbances, whose frequencies are below the hearing range of the human ear. Large explosions in the atmosphere generate infrasonic signals that may propagate thousands of kilometers, and may be recorded by sensitive pressure sensors called microbarographs. The sensors are devices which, like microphones, passively listen for any incoming signals. An array of these sensors acts as an antenna that permits the identification of the direction of arrival of an infrasonic signal, and thus facilitates the location of its source. Such an array will be deployed in the Kahalu'u forest, in a land parcel with controlled access and ideal environmental conditions.
Wind is the primary source of infrasonic noise. Just as it is difficult to talk during a strong gale, it is also difficult to record infrasonic signals when the winds are strong. Gusts of wind travel as large eddies, and the size of these eddies usually scale with the intensity of the wind. Trees form a natural barrier that breaks up these eddies, and thus reduce infrasonic noise. The ideal site for an infrasound station is a well-forested area with low winds, minimal volcanic hazard, view to the horizon, low slope, some security, and available access. Central Kona is unique in that Mauna Loa, Mauna Kea, and Hualalai block the prevailing trade winds, so that there are effectively no trades in the area. An infrasonic survey performed on June 1999 in Kahalu'u forest demonstrated that the site satisfies the CTBT station requirements, and may have some of the lowest noise levels of the global IMS network. Biological and archaeological surveys of the area have demonstrated that there are no sensitive artifacts, flora, or fauna in the selected site. Construction of infrasound array is scheduled to begin after final approval from the landowner, Bishop Estate, and the Department of Land and Natural Resources.
Infrasonic data recorded by the infrasound array in the Kahalu'u forest will be sent via radio to an Infrasound Laboratory (ISLA) housed within the main compound of the Natural Energy Laboratory of Hawaii Authority (NELHA). The primary aim of the ISLA is to ingest and analyze data from the infrasound array in Kona and other IMS stations in the Central Pacific. The ISLA will provide computational resources, secure communication lines, and maintenance staff and equipment to service infrasound CTBT stations in the North Central Pacific.
A public presentation that will discuss the installation and operation
of CTBT sites in Hawai'i will be given at the NELHA conference room on Oct.
29 at 5:30 p.m.