Acoustics experts to sound off in Waikiki
A prototype acoustical surveillance system developed by University of Hawaii-Manoa researcher Milton Garces to warn airplanes of dangers in volcanic zones will be described at an international acoustical meeting here tomorrow through Saturday.
Garces' paper will be among more than 1,600 presented at the fourth joint meeting of the Acoustical Society of America and Acoustical Society of Japan at the Sheraton Waikiki and Royal Hawaiian hotels.
Acoustics is the science of sound.
Garces' acoustical system, known as ASHE, was tested in January by a research team in Ecuador, which has many active volcanoes.
The system detected infrasound -- sound waves too low-pitched for the human ear to detect -- associated with explosions, seismic activity and flows of debris, according to a brief abstract of his paper.
"ASHE detected distinctly different infrasound signals for potentially dangerous ash-rich eruptions (July and August 2006) and a less risky eruption (May 2006) that injected very little ash in the atmosphere," Garces wrote.
He said the results suggest infrasonic monitoring can provide valuable eruption information that could improve early-warning systems for aviation safety.
More than 200 aircraft have encountered volcanic ash in the past 20 years, his paper said. There were no catastrophes, but engine power was lost in seven cases. "Yet major limitations exist with current methods of detecting ash at high altitudes," he said in his paper.
"After eruptions, large swaths of airspace are often closed for unnecessarily long periods of time, causing increased costs and delays."
Among other papers:
» Hiroaki Shimokawa of Tohoku University's Graduate School of Medicine in Japan will present a new medical acoustics application suggesting sound waves might provide a noninvasive means to restore blood flow in patients with coronary artery disease.
» Neb Duric of the Karmanos Cancer Institute in Detroit will describe a three-way ultrasound device to examine beast tissue, eliminating radiation and breast compression and reducing false positive findings involved with X-ray mammography.
» Acoustical consultant David Lubman will present a detailed study of the 1,100-year-old Great Ball Court at Chichen Itza in Mexico explaining its acoustical features. Visitors 460 feet apart can hear each other whisper via a "whispering gallery" between two temples, according to his abstract.
"A profound set of echoes is heard between the playing field's two massive parallel walls, about 270 feet long, 28 feet high and 119 feet apart."
The language of humpback whales, noise hazards from power tools, the influence of native languages on sound perception, cocktail party noises and the mysteries of animal vocalizations are among other topics of the papers.
