. Military Space News .




.
NUKEWARS
Satellite imagery detects thermal "uplift" signal of underground nuclear tests
by Staff Writers
Corvallis OR (SPX) Jan 12, 2012

File image.

A new analysis of satellite data from the late 1990s documents for the first time the "uplift" of ground above a site of underground nuclear testing, providing researchers a potential new tool for analyzing the strength of detonation.

The study has just been published in Geophysical Research Letters.

Lead author Paul Vincent, a geophysicist at Oregon State University, cautions that the findings won't lead to dramatic new ability to detect secret nuclear explosions because of the time lag between the test and the uplift signature, as well as geophysical requirements of the underlying terrain. However, he said, it does "provide another forensic tool for evaluation, especially for the potential explosive yield estimates."

"In the past, satellites have been used to look at surface subsidence as a signal for nuclear testing," said Vincent, an associate professor in OSU's College of Earth, Ocean, and Atmospheric Sciences.

"This is the first time uplift of the ground has correlated to a nuclear test site. The conditions have to be just right and this won't work in every location.

"But it is rather interesting," he added. "It took four years for the source of the uplift signal - a thermal groundwater plume - to reach the surface."

The focus of the study was Lop Nor, a nuclear testing site in China where three tests were conducted - May 21, 1992; May 15, 1995; and Aug. 17, 1995. Vincent and his colleagues analyzed interferometric synthetic aperture radar (InSAR) images from 1996-99 and detected a change in the surface beginning four years after the tests.

Though the uplift was less than two inches, it corresponds to known surface locations above past tests within the Lop Nor test site.

From past studies, the researchers knew that heat from underground detonation of nuclear devices propagates slowly toward the surface. At most sites - including the Nevada National Security Site - that heat signal dissipates laterally when it reaches the water table, which is usually deep beneath the surface.

At Lop Nor, however, the water table is only about three meters below the surface, and the heated groundwater plume took four years to reach that high, lifting the ground above the detonation site slightly - but enough to be detected through InSAR images.

Lop Nor also is characterized by a hard granite subsurface, which helps pipe the heated water vertically and prevents the subsidence frequently found at other testing sites.

A past study by Vincent, published in 2003, first shed light on how subsidence can manifest itself in different ways - from the force of the explosion creating a crater, to more subtle effects of "chimneying," in which the blast opens up a chimney of sorts and draws material downward, creating a dimple at the ground surface.

Before joining the OSU faculty in 2007, Vincent spent several years as a physicist at the Lawrence Livermore National Laboratory.

Vincent said the analysis of nuclear explosions has become a specialized field. Seismology technology can provide an initial estimate of the energy of the explosion, but that data is only good if the seismic waves accurately reflect coupling to the connecting ground in a natural way, he explained. Efforts are sometimes made to "decouple" the explosive device from the ground by creating specializing testing chambers that can give off a false signal, potentially masking the true power of a test.

"Subsidence data combined with seismic data have helped narrow the margin of error in estimating the explosive yield," Vincent noted, "and now there is the potential to use test-related thermal expansion as another forensic tool."

Co-authors on the paper with Vincent include Sean Buckley of the Jet Propulsion Laboratory, Dochul Yang, the University of Texas-Austin, and Steve Carle, of Lawrence Livermore National Laboratory.

Related Links
Oregon State University
Learn about nuclear weapons doctrine and defense at SpaceWar.com
Learn about missile defense at SpaceWar.com
All about missiles at SpaceWar.com
Learn about the Superpowers of the 21st Century at SpaceWar.com




.
.
Get Our Free Newsletters Via Email
...
Buy Advertising Editorial Enquiries






.

. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle



NUKEWARS
Cabin -- with nuclear missile silo -- for sale
New York (AFP) Jan 4, 2012
For sale: one idyllic wooden cottage - with nuclear missile silo attached. The upstate New York property, listed by Sotheby's for $1.76 million, looks like a typical weekend chalet in the forested Adirondack Mountains. At least, that's what's above ground. But punch in a keypad code to open the door, head down some steep stairs and you enter another world. First comes the old underg ... read more


NUKEWARS
Missile Defense "National Team" Awarded C2BMC Contract

US hopes for missile shield accord this year: report

U.S. companies key to gulf missile shield

Raytheon Awarded contract for New Missile Defense Interceptor

NUKEWARS
Raytheon Receives Contract for Patriot Missile Upgrades

Briton loses US extradition fight over Iran missile claims

Helsinki green-lights Patriot missile shipment to SKorea

Missile shipment leaves Finland for South Korea

NUKEWARS
Australia buys portable UAV landing mat

US drone strike kills four militants: Pakistan officials

US drone attack kills four militants in Pakistan

Raven Industries completes Vista Research Acquisition

NUKEWARS
Raytheon's Navy Multiband Terminal Tests With On-Orbit AEHF Satellite

Northrop Grumman And ITT Exelis Team For Army Vehicular Radio

Lockheed Martin Ships First Mobile User Objective System Satellite To Cape For Launch

Satellite Tracking Specialist, Track24, wins Canadian Government Contract

NUKEWARS
Lockheed Martin F-35 Program Exceeds 2011 Flight Test Goals

Raytheon and Thales Australia Deliver Next Generation Desktop to Australia's DoD

US Army Testing Demonstrates Readiness of Raytheon's MAINGATE Radio

Raytheon Awarded Contract for US Air Force Field Service Support

NUKEWARS
Bulgaria, Israel sign training, arms industry deals

China bids farewell to pandas bound for France

US to withdraw about 7,000 troops from Europe: Panetta

IAI clinches $1 billion India arms deal

NUKEWARS
India, China resume border talks in Delhi

Commentary: Asian Finlandization?

Outside View: Two-legged stools don't work

Commentary: Pravda redux

NUKEWARS
Rheinmetall demonstrates laser weapons

LockMart Directed Energy Leader Receives Purdue's Outstanding Aerospace Engineer Award


.

The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement