PROBLEMS OF GEOCOSMOS

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Appendix. Data and Methods
There were processed data from 5 seismic arrays ASAR, FINES, KURK, PDAR and YKA that
registered Chinese explosions dated June 8, 1996, May 15 and August 17, 2005 [Waldhauser et al., 2004],
and four source arrays incorporating vertical records of stations BRVK, COL, KEV, LON that recorded 29,
13, 10 and 23 Semipalatinsk explosions accordingly (Fig.1). The source arrays incorporate same instrument
records and comply with plane wave approximation in terms of their aperture (Fig. A1). The configurations
and Array Response Functions (ARF) for the resulting source arrays obtained from integrating vertical
components of three-component records are given in Fig. A1. The presented ARFs are estimated as slowness
diagrams calculated for “white noise” with Gaussian amplitude distribution supplied to all channels of the
array. The calculated ARF for source arrays recorded by BRVK, COL and LON show excellent
characteristics, and the source array recoded at KEV features no “side lobes” for the actual azimuth to
station.
Before main processing, all data were visually inspected for presence of glitches, abnormal locally
dominating amplitudes or zero traces that frequently result in false arrivals on the sum trace or other output
plots. Additionally, to adjust for slightly different magnitude of events incorporated into a source array (5.9 <
mb < 6.1), scaling factors normalizing to P or cross-correlated PcP waveforms in the array were applied to
individual traces. The effective scaling factors varied between 0.85 and 1.2. Array records were then
bandpass filtered using a Butterworth three-pole zero-phase octave filter with one of the following octaves 1
– 2 Hz, 1.4 – 2.8 Hz, 2 – 4 Hz, 2.4 – 4.8 Hz, 2.8 – 5.6 Hz. The information on dominating oscillation in a
predefined time window was obtained from the slowness diagram calculated in two-dimensional cartesian
system of slowness vectors Sx and Sy, where beam power in the predefined time window was defined as
r.m.s. amplitude with linear beams. Except for paths #1and #2 (see Table 1), where slowness diagrams were
calculated with bounds –0.2 to 0.2 s/km due to low velocity of first arrival, all the diagrams were estimated
between –0.1 and 0.1 s/km using an increment of 0.0008 s/km for both slowness components. Slowness
diagrams were evaluated both in the “absolute time” mode and P-relative which meant aligning of array
traces on the first arrival of a P wave by means of a cross-correlation technique prior to stacking and
application of f-k analysis. Such P-relative slowness diagrams provide better accuracy, as they are
independent of UNE’s origin times and possible errors of station clocks. We then chart a coda decay curve
which is essentially a set of slowness diagrams’ maxima calculated in a sliding window:
⎪⎧
t+ τ n
2
⎤ ⎪⎫
2
−1
⎡ −1
F ( t)
= max⎨τ
∫ ⎢n
∑ f ( t'−kri
) ⎥ dt'⎬
,
k ⎣ i=
1 ⎦
⎪⎩
τ
where f(t-kri) – seismogram at array receiver “i”, n – number of receivers in the array, k – wave vector, ri –
radius vector to the receiver, τ - predefined time window in seconds. Figure A2 shows coda decay curves
estimated in the frequency band 2 – 4 Hz using 1 second sliding window. To track slowness and azimuth of
arriving coda oscillations in time, we compose a movie whose frames are successive slowness diagrams.
Fig. A1. Configurations and Array Response Functions for source arrays formed out of Semipalatinsk explosions recorded at stations
BRVK, COL, KEV and LON (from top to bottom accordingly). Dates of explosions are given in the dd.mm.yyyy format. Reference
points’ coordinates in configuration maps from top to bottom are: (49.942° N; 78.871° E), (49.924° N; 78.820° E), (49.916° N;
78.807° E) and (49.923° N; 78.838° E):
426
⎪⎭