TOURNAI (BE)
Quarry blast1 December 2021
- Magnitude
- 1.4ML
- Depth
- –
- Belgian time
- 13:00:192021-12-01
- UTC
- 12:00:192021-12-01
Main parameters
| Date and time | 2021-12-01 12:00:19 UTC 2021-12-01 13:00:19 Belgian time |
|---|---|
| Magnitude | ML 1.4 |
| Epicentral coordinates | 50.637° N, 3.365° E Uncertainty ± 6.7 km |
| Event ID | ROB 14920 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-12-06 13:52:03 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
- 9
- Epicentral distance
- 34.8 – 125.3km
- Mean velocity, P wave
- 6.5km/s
- Mean velocity, S wave
- 3.8km/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 0.35 s. S wave: 4 measurements, root-mean-square deviation 0.21 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)9 stations | |||||
| LESLessines | 34.8 | 76 | 12:00:26.08+6.75 s | 12:00:29.94+10.61 s | 3.86 |
| SKQSteenkerque | 50.6 | 88 | 12:00:28.22+8.89 s | 12:00:34.47+15.14 s | 6.25 |
| BRQBracquegnies | 57.3 | 107 | 12:00:29.47+10.14 s | – | – |
| RQRRonquières | 60.9 | 93 | 12:00:29.82+10.49 s | – | – |
| SNFSeneffe | 66.6 | 102 | 12:00:30.73+11.40 s | 12:00:38.41+19.08 s | 7.68 |
| UCCBUccle | 72.5 | 75 | 12:00:31.67+12.34 s | – | – |
| OSTBOostende | 73.3 | 336 | 12:00:32.85+13.52 s | 12:00:39.92+20.59 s | 7.07 |
| TGATangissart | 81.9 | 92 | 12:00:33.19+13.86 s | – | – |
| GESGesves | 125.3 | 102 | 12:00:40.50+21.17 s | – | – |