LESSINES (BE)
Quarry blast4 October 2021
- Magnitude
- 1.4ML
- Depth
- –
- Belgian time
- 14:48:232021-10-04
- UTC
- 12:48:232021-10-04
Main parameters
| Date and time | 2021-10-04 12:48:23 UTC 2021-10-04 14:48:23 Belgian time |
|---|---|
| Magnitude | ML 1.4 |
| Epicentral coordinates | 50.713° N, 3.845° E Uncertainty ± 6.6 km |
| Event ID | ROB 14570 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-10-05 10:47:34 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
- 13
- Epicentral distance
- 0.3 – 162.2km
- Mean velocity, P wave
- 5.4km/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: 9 measurements, root-mean-square deviation 0.43 s. S wave: 5 measurements, root-mean-square deviation 0.37 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)12 stations | |||||
| LESLessines | 0.3 | 208 | 12:48:23.32−0.16 s | 12:48:23.79+0.31 s | 0.47 |
| SKQSteenkerque | 18.1 | 113 | 12:48:26.01+2.53 s | 12:48:28.37+4.89 s | 2.36 |
| RQRRonquières | 29.4 | 114 | 12:48:27.67+4.19 s | – | – |
| BRQBracquegnies | 33.0 | 141 | 12:48:29.02+5.54 s | – | – |
| SNFSeneffe | 38.4 | 126 | 12:48:29.44+5.96 s | 12:48:34.92+11.44 s | 5.48 |
| DOUDourbes | 87.0 | 142 | 12:48:38.81+15.33 s | – | – |
| GESGesves | 95.3 | 112 | 12:48:41.27+17.79 s | 12:48:52.46+28.98 s | 11.19 |
| CLAClavier | 108.3 | 107 | 12:48:43.06+19.58 s | 12:48:56.77+33.29 s | 13.71 |
| RCHRochefort | 116.2 | 122 | 12:48:44.05+20.57 s | – | – |
| MEMHMembach | 153.5 | 93 | 12:48:49.19+25.71 s | – | – |
| MEMSMembach | 153.5 | 93 | 12:48:49.23+25.75 s | – | – |
| TNLTernell | 162.2 | 94 | 12:48:50.34+26.86 s | – | – |
| Dutch seismic network (KNMI)1 station | |||||
| HGNHeimansgroeve | 147.4 | 87 | 12:48:48.16+24.68 s | – | – |