LESSINES (BE)
Quarry blast17 November 2021
- Magnitude
- 1.5ML
- Depth
- –
- Belgian time
- 12:40:102021-11-17
- UTC
- 11:40:102021-11-17
Main parameters
| Date and time | 2021-11-17 11:40:10 UTC 2021-11-17 12:40:10 Belgian time |
|---|---|
| Magnitude | ML 1.5 |
| Epicentral coordinates | 50.714° N, 3.863° E Uncertainty ± 4.2 km |
| Event ID | ROB 14780 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-11-18 10:48:56 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
- 1.4 – 146.1km
- Mean velocity, P wave
- 5.5km/s
- Mean velocity, S wave
- 3.2km/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 0.21 s. S wave: 5 measurements, root-mean-square deviation 0.34 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)8 stations | |||||
| LESLessines | 1.4 | 257 | 11:40:11.25+0.26 s | – | – |
| SKQSteenkerque | 17.0 | 115 | 11:40:13.87+2.88 s | 11:40:16.24+5.25 s | 2.37 |
| RQRRonquières | 28.3 | 115 | 11:40:15.75+4.76 s | – | – |
| BRQBracquegnies | 32.3 | 143 | 11:40:16.84+5.85 s | – | – |
| SNFSeneffe | 37.4 | 127 | 11:40:17.42+6.43 s | 11:40:22.18+11.19 s | 4.76 |
| TGATangissart | 48.2 | 104 | 11:40:19.11+8.12 s | 11:40:24.93+13.94 s | 5.82 |
| DOUDourbes | 86.3 | 143 | 11:40:26.51+15.52 s | 11:40:37.17+26.18 s | 10.66 |
| RCHRochefort | 115.2 | 122 | 11:40:31.87+20.88 s | 11:40:46.48+35.49 s | 14.61 |
| Dutch seismic network (KNMI)1 station | |||||
| HGNHeimansgroeve | 146.1 | 87 | 11:40:36.16+25.17 s | 11:40:54.23+43.24 s | 18.07 |