Document Details


Title:
OPERATION SUN BEAM, SHOT SMALL BOY, PROJECT OFFICERS REPORT-PROJECT 1.2: CLOSE-IN EARTH MOTION (DELETED)
Author(s):
SWIFT, L M [STANFORD RESEARCH INSTITUTE]; EISLER, J D [STANFORD RESEARCH INSTITUTE]
Subject Terms:
SUNBEAM PROJECT; DOMINIC II OPERATION; SMALL BOY EVENT; SURFACE EXPLOSIONS; SURFACE PROPERTIES; BLAST EFFECTS; MEASURING METHODS
Document Location:
Location - NNSA/NSO Nuclear Testing Archive Address - P.O. Box 98521 City - Las Vegas State - NV Zip - 89193-8521 Phone - (702)794-5106 Fax - (702)862-4240 Email - CIC@NV.DOE.GOV
Document Type:
REPORT
Publication Date:
1965 Mar 25
Declassification Status:
Sanitized
Document Pages:
0068
Accession Number:
NV0051057
Document Number(s):
POR2201EX
Originating Research Org.:
STANFORD RESEARCH INSTITUTE
OpenNet Entry Date:
1994 Aug 26
Description/Abstract:
SURFACE AND SUBSURFACE GROUND MOTION MEASUREMENTS PRODUCED BY A NUCLEA R SURFACE BURST (SHOT SMALL BOY) [ ] WERE ANALY ZED. OBSERVED ACCELERATION AND VELOCITY WAVE FORMS AT 5-FOOT DEPTHS A ND AT RANGES 290 TO 675 FEET FROM GROUND ZERO RESEMBLED IDEALIZED WAVE FORMS CHARACTERISTIC OF THE PLAYA- AND ALLUVIUM- COVERED AREAS AT THE NEVADA TEST SITE. MORE COMPLEX WAVE FORMS CHARACTERIZED THE OUTPUT O F DEEPER GAGES, INDICATING POSSIBLE ARRIVALS OF REFRACTED WAVES. IT W AS NOTED THAT, CONTRARY TO THEORETICAL PREDICTIONS, THE DIFFERENTIAL T IME OF ARRIVAL BETWEEN THE OVERPRESSURE PULSE AT THE SURFACE AND THE A CCELERATION PULSE AT 5-FOOT DEPTH INCREASED SYSTEMATICALLY WITH INCREA SING RANGE FROM GROUND ZERO. THE OBSERVED EFFECT MAY HAVE BEEN CAUSED BY THE COMPACTION OF THE NEAR-SURFACE LAYERS IN THE REGION OF HIGH OV ERPRESSURE AND THE CONSEQUENT INCREASE OF THE NEAR-SURFACE PROPAGATION VELOCITY. THE DATA FOR SHOT PRISCILLA DID NOT SHOW SUCH A SYSTEMATIC TREND. PARTICLE VELOCITY DATA OBTAINED FROM GAGES LOCATED AT SEVERAL DEPTHS IN A DRILL HOLE AT GROUND ZERO INDICATE HIGHER ATTENUATION WIT H DEPTH AND SUBSTANTIALLY LOWER MAGNITUDE OF VELOCITY THAN HAD BEEN PR EDICTED THEORETICALLY. DATA OBTAINED FROM THE ARRAYS OF VERTICAL COMP ONENT VELOCITY GAGES PLACED AT DEPTH INTERVALS IN DRILL HOLES AT 200 A ND 290 FEET FROM GROUND ZERO SUGGEST THAT THE ATTENUATION OF PARTICLE VELOCITY WITH DEPTH LIES BETWEEN THEORETICAL DIVERGENCE LOSSES CORRESP ONDING TO POINT AND LINE SURFACE SOURCES. THE DATA OBTAINED ON SHOT P RISCILLA INDICATE THAT THE ATTENUATION OF PARTICLE VELOCITY WITH DEPTH CORRESPONDS TO THE THEORETICAL DIVERGENCE LOSS FROM A LINE SURFACE SO URCE. THIS BEHAVIOR MAY BE ASCRIBED TO THE GEOMETRY OF THE PRESSURE W AVE FRONT WHICH ACTS AS THE SEISMIC INPUT TO THE EARTH. OBSERVED ANOM ALOUS RESPONSE OF THE HORIZONTAL-RADIAL COMPONENT VELOCITY GAGES AT 5- FOOT DEPTH FOR SMALL BOY, WHICH INDICATED FIRST MOTION TOWARD THE SOUR CE, COULD HAVE BEEN CAUSED EITHER BY A SPURIOUS RESPONSE OF THESE GAGE S TO THE HIGH-AMPLITUDE VERTICAL COMPONENT ACCELERATION OR BY THE SENS ITIVITY OF THESE GAGES TO ANGULAR MOTION. AT GREATER DEPTHS (60 TO 15 0 FEET) THE OBSERVED COMBINATION OF THE VERTICAL AND HORIZONTAL-RADIAL COMPONENTS OF VELOCITY CONFIRMED THEORETICALLY PREDICTED ARRIVAL OF S HEAR WAVES, WHOSE FIRST MOTION IS DOWN AND TOWARD GROUND ZERO. HOWEVE R, THE RATIO OF THE VELOCITY COMPRESSIONAL WAVES TO THAT OF SHEAR WAVE S AS DETERMINED FROM THE TIME OF ARRIVAL OF THESE EVENTS WAS FOUND TO BE LOWER THAN WOULD BE EXPECTED ON THE BASIS OF SIMPLE ELASTIC THEORY.


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