TOURNAI (BE)
Quarry blast8 December 2021
- Magnitude
- 1.4ML
- Depth
- –
- Belgian time
- 12:36:092021-12-08
- UTC
- 11:36:092021-12-08
Main parameters
| Date and time | 2021-12-08 11:36:09 UTC 2021-12-08 12:36:09 Belgian time |
|---|---|
| Magnitude | ML 1.4 |
| Epicentral coordinates | 50.670° N, 3.443° E Uncertainty ± 7.0 km |
| Event ID | ROB 14960 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-12-10 09:52:21 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
- 28.6 – 199.9km
- Mean velocity, P wave
- 5.7km/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: 4 measurements, root-mean-square deviation 0.73 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.
Station measurements
P- and S-wave arrivals and ground displacement measured at each station. Click a column heading to change the order.
| km | ° | UTC | UTC | s | |
|---|---|---|---|---|---|
| Belgian seismic network (Royal Observatory of Belgium)7 stations | |||||
| LESLessines | 28.6 | 81 | 11:36:14.57+5.41 s | 11:36:18.23+9.07 s | 3.66 |
| SKQSteenkerque | 45.1 | 93 | 11:36:16.61+7.45 s | 11:36:22.39+13.23 s | 5.78 |
| MRDMaredsous | 102.5 | 113 | 11:36:28.19+19.03 s | – | – |
| DOUDourbes | 103.9 | 128 | 11:36:26.57+17.41 s | 11:36:39.67+30.51 s | 13.10 |
| CLAClavier | 134.7 | 101 | 11:36:31.53+22.37 s | 11:36:49.70+40.54 s | 18.17 |
| RCHRochefort | 139.1 | 114 | 11:36:32.52+23.36 s | 11:36:49.09+39.93 s | 16.57 |
| KLBKalborn | 199.9 | 107 | 11:36:40.73+31.57 s | 11:37:01.24+52.08 s | 20.51 |