Joint interpretation of infrasound, acoustic, and seismic waves from meteorites: Chelyabinsk bolide and other events

International Data Centre Page 1
Joint interpretation
of infrasound, acoustic, and seismic waves from
meteorites: Chelyabinsk bolide and other
events
I. Kitov, M. Rozhkov, D. Bobrov, and V. Ovtchinnikov
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
Institute of Geosphere Dynamics,
Russian Academy of Science,
Moscow
Mikhail.Rozhkov@ctbto.org

Outline
• Sources of signals
• Peak energy release. Acoustic (low-amplitude shock) wave
• Infrasound source vs. seismic source
• Seismic waves: Pn, Lg
• Acousto-seismic waves: LR, LQ
• Comparison with atmospheric nuclear tests: Love and Rayleigh waves
• Comparison with the 1987 Chulym and 2002 Vitim meteorites

International Data Centre
Source and energy
(discussed at AGU-2013)
Ek = mV2/2
m0 = 1.3 · 107 kg V0 = 1.9 ·104 m/s
Ek = 2.35 · 1016 J
Yield(1 kt TNT = 4.18 · 1012 J) = 560 kt
Flight time ~20 s; Flight distance ~350 km
Height of entry into atmosphere ~90 km
Peak light emission ~ between 35 km and 25 km
Peak shock wave ~ between 35 km and 20 km

Seismic source
(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
Shock wave

Source shape and evolution
Simplistic model
Real case evolution
Olga P. Popova et al.
Chelyabinsk Airburst,
Damage Assessment,
Meteorite Recovery, and
Characterization
Science 342, 1069 (2013)

Seismic observations: Pn

Location. SSSC- Source Specific Station Corrections
Pn : 55.06 º N, 60.92º E. Ellipse: Smaj=23.5 km, Smin =15.3 km
MKAR AKTO ARU
KURK BVAR

Seismic observations: Lg

Seismic observations:
Lg waves magnitude estimation
5 stations: ARU, AKTO, BVAR, KURK, and MKAR
Station A, nm log(A) Δ, deg 0.83*log(Δ)
Q=400, V=3.5,
f=0.5 Hz mLg
ARU 116 2.064 1.9 0.231 0.001 3.11
AKTO 39 1.591 5 0.580 0.004 2.98
BVAR 17.5 1.243 5.9 0.640 0.004 2.70
KURK 17.3 1.238 11.5 0.880 0.008 2.94
MKAR 12.2 1.086 15.8 0.995 0.012 2.90
mLg = log(A) + 0.81+ 0.83log(Δ) + γ(Δ-0.09)0.434 ; Nuttly, 1986
mLg = 2.93 ± 0.15

Seismic observations: LR
ARU
AKTO
BVAR
KURK
AAK
OBN
MKAR
KBZ

Seismic observations: LR
magnitude 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 IMS stations
(also detected at ARU,
AKTO, and KURK)
Ms(IDC) = 3.95 ± 0.06
Ms(IDC)max = 4.35 (ZALV
and MKAR)
Ms(IDC)min =3.20 (OBN)
Ms > Ms(DPRK2013)=3.9
Δmax= 74º !

Seismic observations, LQ
NRIK
SPITS

Atmospheric nuclear 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)

Location
Pn : 55.06 º N, 60.92º E, Smaj=23.5, Smin=15.3
LR/LQ : 54.81º N, 62.23º E, Smaj=2.5 km, Smin =1.6 km (no modelling error)
I : 53.52º N, 66.59º E, Smaj=376 km, Smin=197 km
REB : 54.06º N, 61.80º E, Smaj=51 km, Smin=13 km
Disintegrated
meteorite
impact zone.
Expected
trajectory:
yellow line

International Data Centre Page 15International Data Centre Page 15
Trajectories published
by Universidad de
Antioquia
http://urania.udea.edu.co/sitios
/facom/research/chelyabinsk-
meteoroid.php?#
Location

Trajectory by BS2013-IAU and
YC2013-NASA, and Universidad
de Antioquia
Location

Chulym meteorite, 1984
26.02.1984, 13:40:00
57.5º N, 85.1º E
Ek ~10 kt
mLg = 3.39
Yield = 0.33kt
(From: Ovchinnikov and Pasechnik, Meteoritika 47,1988)

Vitim bolide, 2002
Expected Pn/Pg and Lg arrivals.
No LR/LQ arrivals to be expected
due to sensor’s limited frequency range.
Infrasound arrivals
at NLYR 3C station
24.09.2002, 16:48:56
57.91º N, 112.90º E
Ek ~2.4 kt
(Adushkin, et al, 2004)
mLg = N/A
Yield = N/A
Data: a courtesy of Baykal Regional Seismic Network, Russian Academy of Sciences

Comparing Chulym, 1984, Chebarkul, 2013, and DPRK 2013
nuclear test
Mag Chulym Chelyabinsk Effect from
ML Not measured 2.4 Hitting the ground
MLg 3.31 2.93 Hitting the ground
Ms Not measured 3.95 Shock wave
What could we say about Chelyabinsk event if we would have only seismic observations?
“UNE case”:
• UNE manifestations at regional seismic stations: Pn, Lg and LR waves.
• Pn and LR locations give different coordinates and can’t be associated as a single source.
Comparing ML with the one determined by IDC from the DPRK-2013 event (ML(IDC)=4.5).
• The DPRK-2013 yield was around 10kt.
• The explosion yield is proportional to the signal amplitude measured when estimating a magnitude.
• From the magnitude measurements we can see that the Chel is almost 100 times smaller (2 magnitude
units).
• The approximate yield of the explosion generating same body waves as Chel is 0.1 kt.

nuclear test
Mag Chulym Chelyabinsk Effect from
ML Not measured 2.4 Hitting the ground
MLg 3.31 2.93 Hitting the ground
Ms Not measured 3.95 Shock wave
If Chel were an atmospheric nuke.
• ATM test phenomena: prominent surface waves (Rayleigh and Love waves).
• UNE: a ratio R of energy transmitted to LR waves to total explosion energy is:
RUNE=ELR/EUNE = 10-6
RAIR= 4*10-8 for Air Nuclear Test
DPRK-2013: Ms = 3.9
• Chel event Ms = 3.95
DPRK-2013 was an underground explosion, Chel was an air explosion, so the equivalent yield of
this meteor explosion must be 25 times higher than the DPRK-2013 test:
Ru/Ra = 25.
So the yield of the air explosion which would generate such waves must be 250Kt.

nuclear test
MLg discussion
• We estimated MLg=2.93 for Chelyabinsk event.
• To generate waves with such magnitude, UNE with the yield Y=0.2 kt must be conducted (according to
Nuttly magnitude scale).
• Though the numbers for Pn and Lg magnitudes are different (0.1kt and 0.2kt), the yields estimated
according to these magnitudes are really close taking into account uncertainties of M to Y conversion
for Lg based measurements.
• Estimation of a kinetic energy corresponding to such explosion gives the mass of the space body
remainder which has hit the ground between 1 and 100 t (the range is due to uncertain meteor velocity,
etc.).
• Different mechanisms of wave generation (Pn and LR) in Chel and Chul cases produce difference in
energy release as respectively 0.5 and 50:
 MLg1 – MLg2 = 3.31 – 2.93 = 0.38 which corresponds approx. to yield ratio of 2.5 (2).
 The meteorite energy estimated by us as ~500kt. Ovchinnikov and Pasechnik (1988) estimated
Chulym meteor yield as 10 kT, so the shock wave energy ratio for these two events is 50.

Conclusions
• Just a small part of the meteorite hit the surface as debris.
• There were at least three sources separated in space and time:
(1) infrasound, (2) LR and LQ, and (3) Pn, Sn, and Lg waves.
• These three sources are located along the meteorite
trajectory.
• Lesson learned: atmospheric nuclear tests are excluded from
CTBT seismic monitoring according to IDC rules (no LR
associated for large Ms-mb differences, no LR associated
without mb).

Thank You!

Joint interpretation of infrasound, acoustic, and seismic waves from meteorites: Chelyabinsk bolide and other events

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