DATE=5/21/98
TYPE=BACKGROUND REPORT
NUMBER=5-40456
TITLE=DETECTING NUKES
BYLINE=JIM RANDLE
DATELINE=PENTAGON 
CONTENT=
VOICED AT:

INTRO:  INDIA'S RECENT NUCLEAR TESTS HAVE FOCUSED NEW ATTENTION 
ON THE SCIENCE AND TECHNIQUE OF DETECTING UNDERGROUND NUCLEAR 
BLASTS.  A NEW GLOBAL MONITORING NETWORK IS NEARING COMPLETION, 
WHILE SCIENTISTS ARE SEEKING MORE EFFICIENT WAYS OF DETECTING 
TESTS.  BUT V-O-A'S JIM RANDLE REPORTS, THE FUNDAMENTALS OF 
REPORTING EVENTS THAT ARE LITERALLY EARTHSHAKING WILL  NOT  
CHANGE MUCH ANYTIME SOON. 

TEXT:       /// SFX:  BIG NUCLEAR EXPLOSION ///

THE TREMENDOUS ENERGY RELEASED BY A NUCLEAR EXPLOSION SHAKES THE 
EARTH.  EVEN STANDING SEVERAL KILOMETERS AWAY, IT IS EASY TO FEEL
THE EARTHQUAKE-LIKE BUMP AS THE EARTH MOVES.  

/// OPT  ///  THIS PARTICULAR SOUND IS FROM AN ABOVE GROUND 
AMERICAN NUCLEAR TEST CONDUCTED DECADES AGO.  ALL RECENT NUCLEAR 
TESTS, INCLUDING THOSE IN INDIA, WERE CONDUCTED UNDERGROUND TO 
KEEP RADIATION FROM SPREADING INTO THE ATMOSPHERE.  /// END OPT 
///

UNIVERSITY OF ARIZONA SEISMOLOGIST TERRY WALLACE HAS BEEN 
TRACKING SUCH EVENTS FOR 25 YEARS.  HE SAYS A ONE KILOTON  
NUCLEAR TEST SHAKES THE EARTH ABOUT THE SAME AS AN EARTHQUAKE 
MEASURING 4-POINT-ONE ON THE RICHTER SCALE.  A ONE KILOTON WEAPON
PUTS OUT THE SAME ENERGY AS A BLAST MADE BY ONE THOUSAND TONS OF 
T-N-T (A POWERFUL CHEMICAL EXPLOSIVE).

PROFESSOR WALLACE SAYS SCIENTISTS CAN TELL THE DIFFERENCE  
BETWEEN A NUCLEAR TEST AND AN EARTHQUAKE, BECAUSE AN EARTHQUAKE'S
ENERGY COMES FROM A WIDER AREA.

                      /// WALLACE ACT  ////

         AN EARTHQUAKE OCCURS ON A FAULT, AND A FAULT IS SPREAD 
         OUT ALONG A LONG LINEAR SEGMENT.  IT'S A BREAK IN THE 
         ROCK, AND THAT BREAK HAS SOME LENGTH, MAYBE A KILOMETER 
         OR TWO KILOMETERS.  BUT AN EXPLOSION RELEASES ALL ITS 
         ENERGY AT A TINY LITTLE POINT, AND BLOWS UP AND AT THAT 
         POINT AND PUSHES OUT.

                         /// END ACT ///

PROFESSOR WALLACE SAYS MEASURING HOW DEEP IN THE EARTH A SEISMIC 
EVENT TAKES PLACE IS A SECOND CLUE ABOUT ITS ORIGIN.  MAN-MADE 
EXPLOSIONS ARE PLACED IN HOLES THAT MAY BE A FEW HUNDRED METERS, 
OR PERHAPS A KILOMETER, DEEP.  EARTHQUAKES GENERALLY OCCUR MUCH 
DEEPER.  

HE SAYS SCIENTISTS CAN ALSO GET USEFUL INFORMATION BY  
DETERMINING IF THE SEISMIC EVENT TOOK PLACE IN A NATION AND PLACE
WHERE NUCLEAR TESTING IS CONSIDERED LIKELY.

TARIQ RAUF OF THE MONTEREY INSTITUTE OF INTERNATIONAL STUDIES 
SAYS SKILLFUL, RELIABLE DETECTION OF NUCLEAR TESTS HELPS DETER 
SUCH EXPLOSIONS, AND IS A KEY PART OF THE COMPREHENSIVE TEST BAN 
TREATY.  MR. RAUF HEADS A GROUP OF SCHOLARS WHO STUDY NUCLEAR 
ISSUES.

HE SAYS A GLOBAL NETWORK OF SEISMIC AND OTHER SENSORS IS NEAR 
COMPLETION, BUT HAS BEEN GIVING USEFUL INFORMATION FOR SOME TIME.
MR. RAUF SAYS SCIENTISTS ARE ALSO USING OTHER WAYS OF DETECTING 
NUCLEAR TESTS TO MAKE SUCH MONITORING MORE COMPLETE AND RELIABLE.

                     ///   RAUF  ACT   /// 

         EVEN THOUGH ONE MAY CONDUCT A TEST UNDERGROUND, THERE 
         ARE CERTAIN RARE GASES THAT ARE CREATED AS A RESULT OF 
         THIS ACTIVITY WHICH EVENTUALLY MAKE THEIR WAY TO THE 
         SURFACE.  AND THESE ARE GASES LIKE ARGON, XENON AND SO 
         ON.  

                         /// END ACT ///

A SCIENTIST AT THE DEPARTMENT OF ENERGY'S PACIFIC NORTHWEST 
NATIONAL LABORATORY (IN RICHLAND, WASHINGTON) SAYS NUCLEAR BLASTS
CHANGE THE MOLECULAR STRUCTURE OF XENON, CREATING RADIOACTIVE 
ISOTOPES OF THE INERT GAS.  SENIOR RESEARCHER TED BOWYER SAYS 
NUCLEAR WEAPONS CREATE A DISTINCTIVE MIX OF ISOTOPES -- A 
SIGNATURE -- UNLIKE ANYTHING CREATED BY NATURE OR LEAKED FROM A 
NUCLEAR POWER PLANT.  

 /// OPT  /// HE HAS COME UP WITH A NEW, FASTER, HIGHLY AUTOMATED
WAY TO SAMPLE LARGE VOLUMES OF AIR AND SORT OUT THE TELLTALE 
XENON FROM A NUCLEAR TEST.  HE USES CHILLED CHARCOAL MADE FROM 
COCONUT, AMONG OTHER THINGS, TO CONCENTRATE THE RARE GAS.  /// 
END OPT  ///   

ANOTHER DETECTION METHOD TRACKS "INFRASOUND," OR THE LOW 
FREQUENCY ACOUSTIC SIGNALS PUT OUT BY AN EXPLOSION.  A FOURTH 
TECHNOLOGY, CALLED HYDRO-ACOUSTIC, LISTENS FOR UNDERWATER TESTS.

MR. RAUF SAYS ALL FOUR TECHNOLOGIES ARE BEING USED IN THE GLOBAL 
MONITORING NETWORK OF HUNDREDS OF STATIONS THAT CURRENTLY REPORT 
DATA TO A PROTOTYPE FACILITY NEAR WASHINGTON.  HE SAYS ONCE THE 
NETWORK IS COMPLETE AND THE COMPREHENSIVE TEST BAN TREATY GOES 
INTO EFFECT, A NEW GLOBAL MONITORING FACILITY WILL BE BUILT IN 
VIENNA (AUSTRIA) AND RUN BY A UNITED NATIONS ORGANIZATION. 
(SIGNED).   

NEB/JR/TMD/MMK

21-May-98 12:58 PM EDT (1658 UTC)
NNNN

Source: Voice of America
.