New computer modeling by a team of researchers indicates that most of the low-frequency infrasound comes from an unexpected source: the actual “pumping” of the Earth’s surface. The researchers confirmed their models by studying data from an actual earthquake.
“It's basically like a loudspeaker,” said Stephen Arrowsmith, a researcher with the Geophysics Group at Los Alamos National Laboratory in Santa Fe, N.M., who presents his team’s findings at the 164th meeting of the Acoustical Society of America (ASA), held Oct. 22 – 26 in Kansas City, Missouri. “In much the same way that a subwoofer vibrates air to create deep and thunderous base notes, earthquakes pump and vibrate the atmosphere producing sounds below the threshold of human hearing.”
Infrasound can reveal important details about an earthquake. In particular, it may be used to measure the amount of ground shaking in the immediate region above the source, which would normally require an array of many seismometers to measure. There is therefore potential to use infrasound to assess damage in the immediate aftermath of an earthquake.
To better understand the relationship between earthquakes and infrasound, the researchers used the basic idea that the Earth’s surface above the earthquake pumps the atmosphere like a piston. They were then able to apply the same modeling approach used on loudspeaker dynamics.
The researchers tested their model by comparing its predictions to actual data collected from a magnitude 4.6-earthquake that occurred on January 3, 2011, in Circleville, Utah. The University of Utah maintains seismograph stations across the state supplemented with infrasound sensors, which recorded the infrasound produced during that event. Their predictions were in good agreement with the actual data, suggesting that earthquakes generate most of their sound by pumping the atmosphere like a loudspeaker.
“This was very exciting because it is the first such clear agreement in infrasound predictions from an earthquake,” said Arrowsmith. “Predicting infrasound is complex because winds can distort the signal and our results also suggest we are getting better at correcting for wind effects.”
Until now, seismologists have not understood the relative importance of the simple pumping of the ground versus other mechanisms for generating infrasound.
Additional members of the research team include Relu Burlacu and Kristine Pankow, University of Utah; Brian Stump and Chris Haward, Southern Methodist University; and Richard Stead and Rod Whitaker, Los Alamos National Laboratory.MORE INFORMATION ABOUT THE 164th ASA MEETING
This news release was prepared for the Acoustical Society of America (ASA) by the American Institute of Physics (AIP).ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
Charles E. Blue | Newswise Science News
Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen
Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research