Can sound help us detect 'earthquakes' on Venus?

April 23, 2015
Seismic waves radiating from a Venus quake propagate as Rayleigh waves in the Venus surface layers and generate infrasonic waves traveling upwards through the dense Venus atmosphere. These low frequency sound waves can be detected by a balloon (upper left) floating within the Venus clouds at an altitude of 55 km where temperatures are similar to those on the Earth's surface. As the infrasonic waves penetrate the clouds and enter the upper atmosphere they produce thermal variations and molecular excitations. These signals can be viewed from space by infrared imaging sensors as an expanding pattern of concentric circles by on the orbiting spacecraft (upper right). Credit: Keck Institute for Space Studies (KISS)

Detecting an "earthquake" on Venus would seem to be an impossible task. The planet's surface is a hostile zone of crushing pressure and scorching temperatures—about 874 degrees F, hot enough to melt lead—that would destroy any of the normal instruments used to gauge seismic activity. But conditions in Venus' atmosphere are much more hospitable, and it is here that researchers hope to deploy an array of balloons or satellites that could detect Venusian seismic activity—using sound.

These kinds of low frequency or infrasonic , much lower than an audible voice, are already measured on Earth. The rumbling or "hum" can be generated by sources as diverse as volcanoes, earthquakes, ocean storms and meteor air blasts. In recent years, says Los Alamos National Laboratory researcher Stephen Arrowsmith, infrasonic observations have undergone a renaissance of sorts, especially as a relatively inexpensive way to monitor atmospheric nuclear weapons tests. But last year, a team of experts convened by the Keck Institute for Space Studies began thinking of ways to use infrasonic observations to get a better look at the geological dynamics of Venus.

At about 50-60 kilometers above Venus' surface, the temperature and pressure conditions are much more like those on Earth, albeit with a denser atmosphere. This dense atmosphere helps translate any seismic waves into infrasonic waves that can be detected with instruments floating above the planet's surface, says Jim Cutts, a Jet Propulsion Laboratory researcher who participated in the Keck conference. Infrasonic waves can be "felt" as either fluctuations in pressure, or as light emissions called airglow, or electron disruptions in Venus' upper atmosphere.

Arrowsmith and colleagues say that barometric pressure changes might be detected with a series of balloons in the Venus cloud layer at 55 kilometers above the surface, such as those launched by the Soviet Union in Venus' atmosphere in the 1980s. In a second talk, Philippe Lognonné and colleagues discuss a complementary way to analyze the planet's infrasonic waves, using orbiting satellites to detect airglow. In both cases, the first goal will be determine what the noise-to-signal ratio might be for these two techniques. The researchers want to know if the instruments onboard a balloon or satellite will be sensitive enough to detect and identify a seismic signal in the midst of other infrasonic waves, and how large of a seismic event might be detected by these observations.

If these techniques can help scientists get a better sense of on the planet, it could tell them more about the history and current state of Venus' interior, the researchers say. Venus' inner evolution would be especially interesting to compare with Earth's, to discover more about the diversity of planet formation and why certain features—such as tectonic plates and a dynamo mechanism in the core—exist on Earth but not on Venus.

James Cutts, Stephen Arrowsmith and Philippe Lognonné will present their findings on April 23 at the annual meeting of the Seismological Society of America.

Explore further: Source of Earth's ringing? French team views ocean waves

Related Stories

Source of Earth's ringing? French team views ocean waves

April 20, 2015

Three researchers in France have authored "How ocean waves rock the Earth: Two mechanisms explain microseisms with periods 3 to 300 s," published in Geophysical Research Letters, a journal of the American Geophysical Union ...

Learn about Venus, the hothouse planet near Earth

February 23, 2015

Venus was once considered a twin to Earth, as it's roughly the same size and is relatively close to our planet. But once astronomers looked at it seriously in the past half-century or so, a lot of contrasts emerged. The biggest ...

NASA considers possibilities for manned mission to Venus

December 18, 2014

(Phys.org) —NASA's Systems Analysis and Concepts Directorate has issued a report outlining a possible way for humans to visit Venus, rather than Mars—by hovering in the atmosphere instead of landing on the surface. The ...

Venus, if you will, as seen in radar with the GBT

March 9, 2015

From earthbound optical telescopes, the surface of Venus is shrouded beneath thick clouds made mostly of carbon dioxide. To penetrate this veil, probes like NASA's Magellan spacecraft use radar to reveal remarkable features ...

Recommended for you

A black hole in a low mass X-ray binary

April 24, 2017

A globular cluster is a roughly spherical ensemble of stars (as many as several million) that are gravitationally bound together, and typically located in the outer regions of galaxies. Low mass X-ray binary stars (LMXBs) ...

Detecting life in the ultra-dry Atacama Desert

April 21, 2017

Few places are as hostile to life as Chile's Atacama Desert. It's the driest non-polar desert on Earth, and only the hardiest microbes survive there. Its rocky landscape has lain undisturbed for eons, exposed to extreme temperatures ...

New look at 2004's martian hole-in-one site

April 21, 2017

A new observation from NASA's Mars Reconnaissance Orbiter (MRO) captures the landing platform that the rover Opportunity left behind in Eagle Crater more than 13 years and 27 miles (or 44 kilometers) ago.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.