TOURNAI (BE)
Quarry blast8 December 2021
- Magnitude
- 1.4ML
- Depth
- –
- Belgian time
- 13:00:072021-12-08
- UTC
- 12:00:072021-12-08
Main parameters
| Date and time | 2021-12-08 12:00:07 UTC 2021-12-08 13:00:07 Belgian time |
|---|---|
| Magnitude | ML 1.4 |
| Epicentral coordinates | 50.604° N, 3.553° E Uncertainty ± 7.0 km |
| Event ID | ROB 14965 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-12-10 09:52:33 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
- 23.7 – 129.1km
- Mean velocity, P wave
- 6.4km/s
- Mean velocity, S wave
- 3.7km/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: 8 measurements, root-mean-square deviation 0.43 s. S wave: 4 measurements, root-mean-square deviation 1.40 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)10 stations | |||||
| LESLessines | 23.7 | 60 | 12:00:12.54+4.62 s | 12:00:15.94+8.02 s | 3.40 |
| SKQSteenkerque | 37.7 | 82 | 12:00:14.37+6.45 s | 12:00:20.13+12.21 s | 5.76 |
| BRQBracquegnies | 43.6 | 108 | 12:00:15.61+7.69 s | – | – |
| RQRRonquières | 47.6 | 89 | 12:00:15.98+8.06 s | – | – |
| SNFSeneffe | 52.9 | 101 | 12:00:16.77+8.85 s | 12:00:24.85+16.93 s | 8.08 |
| TGATangissart | 68.6 | 90 | 12:00:19.41+11.49 s | 12:00:25.50+17.58 s | 6.09 |
| DOUDourbes | 93.3 | 127 | 12:00:24.24+16.32 s | – | – |
| GESGesves | 111.6 | 102 | 12:00:26.89+18.97 s | – | – |
| CLAClavier | 125.8 | 99 | 12:00:29.21+21.29 s | – | – |
| RCHRochefort | 129.1 | 112 | 12:00:30.28+22.36 s | – | – |