International Data Centre Page 1
The DPRK 2013 underground test and Chebarkul meteorite:
joint interpretation of seismic, ...
International Data Centre Page 2
Outline
1. The 2013 DPRK underground test
• Seismic wavefield. Cross comparison
• Seismoa...
International Data Centre Page 3
Seismic waves: cross comparison
2013 vs. 2009 : KSRS and USRK
2009
2013
2009
2013
International Data Centre Page 4
Seismic waves: cross correlation relative location
Final location is based on reciprocal ...
International Data Centre Page 5
DPRK 2013: LR
Ms(IDC)=3.9
USRK
KSRS
TLY
Z
H1
H2
Z
H1
H2
Z
H1
H2
International Data Centre Page 6
DPRK 2013: LR
Ms(IDC)=3.9
OBN
BVAR
AKTO
SPITS
LQ?
Z
H1
H2
International Data Centre Page 7
Epicentral seismoacoustic waves:
total energy
R
u(0)
r
u(r)
P(r) = ρCu(r)
u(r) = Ar-n
n>1...
International Data Centre Page 8
Local seismoacoustic waves
seismic vs. infrasound waveforms
Infrasound channel measures p...
International Data Centre Page 9
Chebarkul meteorite: source and energy
Ek = mV2/2 Ek = 1.62 · 1016 J
m0 = 108 kg 1 kt = 4...
International Data Centre Page 10
Chebarkul meteorite: source and energy
Flight time ~20 s; Flight distance ~350 km
Flight...
International Data Centre Page 11
Chebarkul meteorite: source and energy
V(1km) = 2500 m/s
m(1km) = 3,700 tons
Ek(1km) = 2...
International Data Centre Page 12
Chebarkul meteorite: seismic source
h
RP2/P1
r
(P2-P1)/P1 < 0.1 (high altitude explosion...
International Data Centre Page 13
Chebarkul meteorite: seismic observations,
Pn, ML=2.4; (ML(REB)=2.2)
Z
ARU N
E
Z
AKTO H1...
International Data Centre Page 14
Chebarkul meteorite: seismic observations
Pn and LgNot the impact!
International Data Centre Page 15
Chebarkul meteorite: seismic observations
No LR associated in the REB!
ARU
AKTO
BVAR
KUR...
International Data Centre Page 16
Chebarkul meteorite: seismic observations,
LR: offline estimation
# STA Phase Delta, deg...
International Data Centre Page 17
Chebarkul meteorite: seismic observations,
LR
1. Ms(IDC) = 3.95
2. ML (REB)=2.2
3. IDC r...
International Data Centre Page 18
Chebarkul meteorite: seismic observations,
LQ
ARU
AKTO
BVAR
KURK
OBN
AAK
MKAR
KBZ
International Data Centre Page 19
Chebarkul meteorite: seismic observations,
LQ
NRIK
SPITS
International Data Centre Page 20
Atmospheric test: seismic observations,
LQ
E-W
Z
time
LQ
LR
Δ =3660 km
1 min
From: Pasec...
International Data Centre Page 21
Location
Pn : 55.06 º N, 60.92º E, Smax=23.5 km, Smin =15.3 km
LR/LQ : 54.81º N, 62.23º ...
International Data Centre Page 22
Chulym meteorite, 1984
26.02.1984, 13:40:00
57.5º N, 85.1º E
mLg = 3.39
Ek ~10 kt
(From:...
International Data Centre Page 23
Local acoustoseismic wave
ARU Z
ARU N
ARU E
Station ARU: acoustoseismic wave 15 min afte...
International Data Centre Page 24
Conclusions
• Infrasound signal from a relatively small underground explosion can be
mea...
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Acoustic and seismic effects of the 2013 Chelyabinsk meteorite as measured by the International Monitoring System and interpreted by the International Dat Centre

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Two events crucial for monitoring of nuclear explosions under the CTBT occurred on February 12 and 15 and attracted attention of the mass media and scientists. Seismic waves from the underground event and infrasound waves from the meteorite are of extreme interest as well as various processes of energy conversion at the free surface. Infrasound station I45(RU) collocated with seismic array USRK recorded the epicentral I-phase generated by the DPRK 2013 event and the seismoacoustic wave emitted beneath the station. The shock wave from the Chebarkul meteorite generated a regular I-phase recorded by many IMS infrasound stations and a series of seismic phases likely associated with impact and acoustoseismic conversion. Due to the altitude of the peak energy release, the air-coupled ground rolls with a group velocity of 3.5 km/s were generated. A similar pattern was observed after the 1984 r.Chulym (Siberia) bolide. We estimate the energy of both sources and discuss possible mechanisms of acoustic/seismic wave generation and conversion.

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Acoustic and seismic effects of the 2013 Chelyabinsk meteorite as measured by the International Monitoring System and interpreted by the International Dat Centre

  1. 1. International Data Centre Page 1 The DPRK 2013 underground test and Chebarkul meteorite: joint interpretation of seismic, infrasound, acoustoseismic, and seismoacoustic waves Kitov, I., D. Bobrov, M. Rozhkov, and K. Sitnikov International Data Centre Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization Provisional Technical Secretariat Vienna International Centre P.O. Box 1200 A-1400 Vienna AUSTRIA ivan.kitov@ctbto.org
  2. 2. International Data Centre Page 2 Outline 1. The 2013 DPRK underground test • Seismic wavefield. Cross comparison • Seismoacoustic effect in the epicentral zone • Local seismoacoustic wave 2. Chebarkul meteorite • Source function • Peak energy release. Acoustic (low-amplitude shock) wave • Infrasound source vs. seismic source • Acoustoseismic waves: Pn, Lg, LR, LQ • Comparison with atmospheric nuclear tests: Love and Rayleigh waves • Comparison with the 1987 Chulym meteorite.
  3. 3. International Data Centre Page 3 Seismic waves: cross comparison 2013 vs. 2009 : KSRS and USRK 2009 2013 2009 2013
  4. 4. International Data Centre Page 4 Seismic waves: cross correlation relative location Final location is based on reciprocal cross- correlation when the estimate is based on mutual master-slave permutation. Distance between events is 590 meters for 4 stations, and 570 meters for 22 stations. X and Y distances are 470 and 360 meters for 4 stations, and 400 and 410 meters for 22 stations. 2009 2013 2009 2013 2006 4 regional arrays 22 IMS arrays Joint relative location Initial master event is DPRK-2009, primary slave is DPRK-2013, and secondary slave is DPRK-2006 .
  5. 5. International Data Centre Page 5 DPRK 2013: LR Ms(IDC)=3.9 USRK KSRS TLY Z H1 H2 Z H1 H2 Z H1 H2
  6. 6. International Data Centre Page 6 DPRK 2013: LR Ms(IDC)=3.9 OBN BVAR AKTO SPITS LQ? Z H1 H2
  7. 7. International Data Centre Page 7 Epicentral seismoacoustic waves: total energy R u(0) r u(r) P(r) = ρCu(r) u(r) = Ar-n n>1 u(r) = v(R) h/R ρ - air density C – sound speed u(r) – vertical velocityv(R) v(R) = Bh-1/4 Y1/3/R Ei/Es ~ 10-4 ; Ei – infrasound energy, Es - seismic energy Ei ~ 10-3 kt h P(0) V(R) – radial velocity; Y – yield; B - constant
  8. 8. International Data Centre Page 8 Local seismoacoustic waves seismic vs. infrasound waveforms Infrasound channel measures particle velocity I45RU USRK USRK I45RU
  9. 9. International Data Centre Page 9 Chebarkul meteorite: source and energy Ek = mV2/2 Ek = 1.62 · 1016 J m0 = 108 kg 1 kt = 4.18 · 1012 J V0 = 1.8 ·104 m/s W = 380 kt Dynamic traction: Pdyn = ρ(h)CDV2 Aerodynamic deceleration dV/dt = - ρ CDV2 /m(t) Dissipation of kinetic energy dE = 0.5V2dm + mVdV Ablation dm/dt = 0.413AΓρV3/Hvap Luminous flux F = -(τV2/8πZ2)dm/dt Energy release history Total energy
  10. 10. International Data Centre Page 10 Chebarkul meteorite: source and energy Flight time ~20 s; Flight distance ~350 km Flight height change ~90 km Height of peak light emission ~ between 30 km and 20 km Duration of peak emission ~ 3 s Length of peak emission ~ 35 km Average energy release per km 380kt/350km =1.1 kt/km (1.1 t/m) Peak energy release ~6 kt/km or 200 kt in total 0 20 40 60 80 100 0 100 200 300 400 500 600 700 height,km dV/dt, m/s·s 0 20 40 60 80 100 0 0.2 0.4 0.6 0.8 1 height,km ρ/ρ0 Peak light emission Normalized Air Density Acceleration
  11. 11. International Data Centre Page 11 Chebarkul meteorite: source and energy V(1km) = 2500 m/s m(1km) = 3,700 tons Ek(1km) = 27 kt E30 to 20 = 150 kt0 20 40 60 80 100 1.E+10 1.E+11 1.E+12 1.E+13 1.E+14 1.E+15 height,km dE/dt, J/s 0.5*V*V*dm m*V*dV 30 km 20 km 0 20 40 60 80 100 0 0.2 0.4 0.6 0.8 1 height,km dE/dt 0 20 40 60 80 100 120 0100200300400 height,km Distance, km P Shock wave Normalized energy release
  12. 12. International Data Centre Page 12 Chebarkul meteorite: seismic source h RP2/P1 r (P2-P1)/P1 < 0.1 (high altitude explosion) P1 - surface atmospheric pressure; P 2 – shock wave pressure ΔP(r,t)/P1 = (ΔP(R0)/P1 )max(1-ta/L+)exp(-ta/L+) ΔP = P2-P1 ; R0 – radius of peak overpressure; t – time; a – sound speed near the surface; L+ - the length of shock wave impact t0 t1 t2 Acousto- seismic source region P2/P1Shock wave Source shape and evolution Nuclear test t1-t0 ~70 sec Δ~100 km Shock wave
  13. 13. International Data Centre Page 13 Chebarkul meteorite: seismic observations, Pn, ML=2.4; (ML(REB)=2.2) Z ARU N E Z AKTO H1 H2 BVAR KURK MKAR
  14. 14. International Data Centre Page 14 Chebarkul meteorite: seismic observations Pn and LgNot the impact!
  15. 15. International Data Centre Page 15 Chebarkul meteorite: seismic observations No LR associated in the REB! ARU AKTO BVAR KURK AAK OBN MKAR KBZ
  16. 16. International Data Centre Page 16 Chebarkul meteorite: seismic observations, LR: offline estimation # STA Phase Delta, deg Ms Ms res 1 BVAR LR 5.22 4.21 0.25 2 ZALV LR 13.53 4.35 0.39 3 AAK LR 14.17 4.11 0.15 4 OBN LR 14.65 3.20 -0.76 5 MKAR LR 14.91 4.35 0.39 6 KVAR LR 16.05 3.91 -0.05 7 KBZ LR 16.12 4.02 0.06 8 GNI LR 18.05 3.94 -0.02 9 NRIK LR 19.33 4.07 0.11 10 AKASG LR 20.07 4.06 0.11 11 FINES LR 20.23 3.23 -0.73 12 BRTR LR 23.79 3.72 -0.24 13 MLR LR 24.47 4.18 0.22 14 HFS LR 26.33 4.02 0.07 15 NOA LR 27.41 3.96 0.00 16 VRAC LR 28.05 4.00 0.05 17 SPITS LR 28.88 3.75 -0.21 18 GERES LR 29.95 4.21 0.26 19 EIL LR 31.17 3.87 -0.09 20 DAVOX LR 33.22 4.28 0.32 21 JMIC LR 34.09 3.71 -0.24 22 BORG LR 40.55 3.91 -0.05 23 CMAR LR 45.55 3.79 -0.17 24 KSRS LR 47.21 4.23 0.27 25 BBB LR 73.81 3.87 -0.09 25 stations (+ARU, AKTO, and KURK) Ms(IDC)max = 4.35 (ZALV and MKAR) Ms(IDC)min =3.20 (OBN) Ms(IDC)ave =3.95 (±0.06) Ms(met) > Ms(DPRK2013) Δmax= 74º !
  17. 17. International Data Centre Page 17 Chebarkul meteorite: seismic observations, LR 1. Ms(IDC) = 3.95 2. ML (REB)=2.2 3. IDC rule: no LR associated for large Ms-mb differences 4. IDC rule: no LR associated without mb 5. Ignores physics of seismic wave generation 6. Ignores historical observations from atmospheric tests 7. What CTBT monitoring misses? • Accurate hypocenter location of atmospheric tests with LR azimuths and travel times • Altitude estimate from periods of LR and LQ • Size estimate from amplitudes and periods • Fusion of seismic and infrasound wavefield • Interpretation of the event nature (nuclear tests vs. meteorites) A major gap in IDC processing at the development stage
  18. 18. International Data Centre Page 18 Chebarkul meteorite: seismic observations, LQ ARU AKTO BVAR KURK OBN AAK MKAR KBZ
  19. 19. International Data Centre Page 19 Chebarkul meteorite: seismic observations, LQ NRIK SPITS
  20. 20. International Data Centre Page 20 Atmospheric test: seismic observations, LQ E-W Z time LQ LR Δ =3660 km 1 min From: Pasechnik, I.P. (1970). Characteristic of seismic waves from nuclear explosions and earthquakes, Nauka (in Russian)
  21. 21. International Data Centre Page 21 Location Pn : 55.06 º N, 60.92º E, Smax=23.5 km, Smin =15.3 km LR/LQ : 54.81º N, 62.23º E, Smax=2.5 km, Smin =1.6 km (no modelling error) I : 53.52º N, 66.59º E, Smax=376 km, Smin =197 km REB : 54.06º N, 61.80º E, Smax=51 km, Smin =13 km Disintegrated meteorite impact zone
  22. 22. International Data Centre Page 22 Chulym meteorite, 1984 26.02.1984, 13:40:00 57.5º N, 85.1º E mLg = 3.39 Ek ~10 kt (From: Ovchinnikov and Pasechnik, Meteoritika 47,1988)
  23. 23. International Data Centre Page 23 Local acoustoseismic wave ARU Z ARU N ARU E Station ARU: acoustoseismic wave 15 min after Pn Δ(Pn) ~ 200 km; Δ(LR/LQ) ~ 280 km Travel time (Pn) = 10 min Travel time (LR/LQ) = 14 min; No signal Signal stronger than Lg October 20, 1962, t0=09-21-45.6, =50.4227, =77.723, Y=6.7 kt, HOB=635 m NCE (328 km). (By the courtesy of Sokolova I.N., IGR Kazakhstan, T2-P57) ~18 min
  24. 24. International Data Centre Page 24 Conclusions • Infrasound signal from a relatively small underground explosion can be measured at near-regional distances • Local infrasound signal generated by seismic wave can be used for relative calibration of seismic and infrasound sensors • The energy of infrasound and seismic sources associated with a meteorite may differ by a factor of 2 • The impact of the Chebarkul meteorite is unlikely. Debris reached the surface • There were at least three sources different in space and time: infrasound, LR and LQ, and Pn waves. • These three sources are located along the trajectory • Local acoustoseismic waves were measured at seismic station ARU • The IDC has a major hole in joint processing of infrasound and seismic waves from atmospheric explosions. In fact, this type of nuclear tests is practically excluded from seismic monitoring • The IDC misses important information on surface wave magnitude of acoustoseismic events, which can be used for screening

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