LESSINES (BE)
Quarry blast9 June 2021
- Magnitude
- 1.7ML
- Depth
- –
- Belgian time
- 12:40:072021-06-09
- UTC
- 10:40:072021-06-09
Main parameters
| Date and time | 2021-06-09 10:40:07 UTC 2021-06-09 12:40:07 Belgian time |
|---|---|
| Magnitude | ML 1.7 |
| Epicentral coordinates | 50.703° N, 3.880° E Uncertainty ± 11.5 km |
| Event ID | ROB 13625 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-06-10 00:20:52 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
- 8
- Epicentral distance
- 15.4 – 151.0km
- Mean velocity, P wave
- 5.5km/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: 6 measurements, root-mean-square deviation 0.42 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 | |||||
| SKQSteenkerque | 15.4 | 113 | 10:40:10.15+2.53 s | 10:40:12.77+5.15 s | 2.62 |
| RQRRonquières | 26.7 | 114 | 10:40:12.13+4.51 s | – | – |
| BRQBracquegnies | 30.6 | 144 | 10:40:13.29+5.67 s | – | – |
| SNFSeneffe | 35.7 | 127 | 10:40:12.85+5.23 s | – | – |
| DOUDourbes | 84.6 | 143 | 10:40:22.84+15.22 s | 10:40:32.69+25.07 s | 9.85 |
| GESGesves | 92.6 | 112 | 10:40:24.04+16.42 s | 10:40:35.12+27.50 s | 11.08 |
| MEMHMembach | 151.0 | 93 | 10:40:33.04+25.42 s | 10:40:52.41+44.79 s | 19.37 |
| Dutch seismic network (KNMI)1 station | |||||
| HGNHeimansgroeve | 145.0 | 87 | 10:40:32.32+24.70 s | 10:40:50.04+42.42 s | 17.72 |