NAMUR (BE)

Quarry blast25 August 2020

Magnitude
1.9ML
Depth
–
Belgian time
13:43:342020-08-25
UTC
11:43:342020-08-25

Main parameters

Date and time2020-08-25 11:43:34 UTC
2020-08-25 13:43:34 Belgian time
MagnitudeML 1.9
Epicentral coordinates50.499° N, 4.976° E
Uncertainty ± 2.0 km
Event IDROB 10735

Data source : ROB (Royal Observatory of Belgium)
Last update : 2020-08-26 09:41:42 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
7
Epicentral distance
26.5 – 92.1km
Mean velocity, P wave
6.1km/s
Mean velocity, S wave
3.5km/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: 7 measurements, root-mean-square deviation 0.44 s. S wave: 5 measurements, root-mean-square deviation 0.54 s.

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)6 stations
MRDMaredsous26.521411:43:39.26+4.37 s11:43:44.02+9.13 s4.76
DOUDourbes52.521111:43:43.89+9.00 s11:43:51.05+16.16 s7.16
RQRRonquières54.528311:43:44.51+9.62 s––
SKQSteenkerque65.628511:43:45.83+10.94 s––
MEMHMembach74.38011:43:47.97+13.08 s11:43:57.54+22.65 s9.57
KLBKalborn92.111811:43:51.30+16.41 s11:44:01.42+26.53 s10.12
Dutch seismic network (KNMI)1 station
HGNHeimansgroeve73.76611:43:47.48+12.59 s11:43:56.84+21.95 s9.36
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