TOURNAI (BE)

Quarry blast27 January 2020

Magnitude
1.8ML
Depth
9.6km ± 4.9
Belgian time
12:30:532020-01-27
UTC
11:30:532020-01-27

Main parameters

Date and time2020-01-27 11:30:53 UTC
2020-01-27 12:30:53 Belgian time
MagnitudeML 1.8
Epicentral coordinates50.663° N, 3.432° E
Uncertainty ± 3.8 km
Depth of hypocenter9.6 ± 4.9 km
Event IDROB 9185

Data source : ROB (Royal Observatory of Belgium)
Last update : 2020-01-27 12:56:37 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
13
Epicentral distance
29.5 – 185.7km
Mean velocity, P wave
6.0km/s
Mean velocity, S wave
3.4km/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. Hypocenter at a depth of 9.6 km. P wave: 9 measurements, root-mean-square deviation 0.46 s. S wave: 5 measurements, root-mean-square deviation 0.69 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°UTCUTCsnm
Belgian seismic network (Royal Observatory of Belgium)13 stations
LESLessines29.58011:30:59.52+5.66 s11:31:03.50+9.64 s3.9856.7
SKQSteenkerque45.99211:31:01.67+7.81 s11:31:07.07+13.21 s5.40–
BOUBougnies47.513011:31:01.46+7.60 s–––
BRQBracquegnies53.811211:31:02.85+8.99 s–––
RQRRonquières56.59611:31:03.23+9.37 s–––
OSTBOostende72.733211:31:06.90+13.04 s–––
TGATangissart77.49411:31:06.02+12.16 s11:31:15.74+21.88 s9.72–
MRDMaredsous103.011211:31:11.00+17.14 s11:31:25.10+31.24 s14.10–
DOUDourbes104.112711:31:11.28+17.42 s11:31:24.92+31.06 s13.64–
GESGesves121.410411:31:13.54+19.68 s–––
CLAClavier135.310111:31:16.30+22.44 s11:31:34.40+40.54 s18.10–
RCHRochefort139.611311:31:16.37+22.51 s–––
HOUHouvegnez185.710011:31:24.41+30.55 s–––
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