TOURNAI (BE)

Quarry blast16 April 2021

Magnitude
1.2ML
Depth
–
Belgian time
11:00:172021-04-16
UTC
09:00:172021-04-16

Main parameters

Date and time2021-04-16 09:00:17 UTC
2021-04-16 11:00:17 Belgian time
MagnitudeML 1.2
Epicentral coordinates50.652° N, 3.575° E
Uncertainty ± 1.9 km
Event IDROB 13160

Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-04-16 13:28:22 Belgian time

Location map

  • Epicentre
  • Station that recorded the event

Arrival times at the stations

Each station first records the P wave, the fastest, then the S wave. The farther a station is from the epicentre, the later the waves reach it and the wider the gap between the two.

Stations
10
Epicentral distance
35.7 – 129.8km
Mean velocity, P wave
5.5km/s
  • P wave
  • S wave
  • Curve fitted to the measurements
Notes and method

Curves: travel time of a direct wave in a homogeneous medium. The velocity of each wave and an origin-time shift, common to both, are fitted to the measurements by least squares. Depth not determined: hypocenter placed at the surface for the calculation. P wave: 9 measurements, root-mean-square deviation 0.49 s.

Stations farther than 120 km are left out of the fit: the first waves to reach them have travelled beneath the crust, through the mantle, where they propagate faster.

Table of measurements

Station measurements

P- and S-wave arrivals and ground displacement measured at each station. Click a column heading to change the order.

km°UTCUTCs
Belgian seismic network (Royal Observatory of Belgium)10 stations
SKQSteenkerque35.79009:00:23.96+6.82 s––
BOUBougnies39.313809:00:24.25+7.11 s––
BRQBracquegnies44.111509:00:25.06+7.92 s––
RQRRonquières46.39609:00:25.45+8.31 s––
SNFSeneffe52.610709:00:26.41+9.27 s––
UCCBUccle57.77309:00:27.41+10.27 s09:00:34.83+17.69 s7.42
OSTBOostende79.032609:00:30.64+13.50 s––
DOUDourbes95.413009:00:33.62+16.48 s09:00:44.33+27.19 s10.71
GESGesves111.310509:00:38.15+21.01 s09:00:48.73+31.59 s10.58
RCHRochefort129.811509:00:40.06+22.92 s––
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