LESSINES (BE)
Quarry blast5 July 2021
- Magnitude
- 1.8ML
- Depth
- –
- Belgian time
- 12:39:432021-07-05
- UTC
- 10:39:432021-07-05
Main parameters
| Date and time | 2021-07-05 10:39:43 UTC 2021-07-05 12:39:43 Belgian time |
|---|---|
| Magnitude | ML 1.8 |
| Epicentral coordinates | 50.732° N, 3.845° E Uncertainty ± 3.5 km |
| Event ID | ROB 13870 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-07-06 17:06:02 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
- 12
- Epicentral distance
- 2.4 – 153.7km
- Mean velocity, P wave
- 5.6km/s
- Mean velocity, S wave
- 3.3km/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 0.28 s. S wave: 5 measurements, root-mean-square deviation 0.56 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)11 stations | |||||
| LESLessines | 2.4 | 183 | 10:39:43.83+0.49 s | – | – |
| SKQSteenkerque | 19.0 | 119 | 10:39:46.42+3.08 s | 10:39:48.92+5.58 s | 2.50 |
| RQRRonquières | 30.3 | 117 | 10:39:48.16+4.82 s | – | – |
| BRQBracquegnies | 34.7 | 143 | 10:39:49.22+5.88 s | – | – |
| SNFSeneffe | 39.7 | 128 | 10:39:49.98+6.64 s | – | – |
| TGATangissart | 49.9 | 106 | 10:39:51.37+8.03 s | 10:39:56.74+13.40 s | 5.37 |
| DOUDourbes | 88.7 | 143 | 10:39:59.07+15.73 s | 10:40:09.67+26.33 s | 10.60 |
| CLAClavier | 109.0 | 108 | 10:40:02.03+18.69 s | 10:40:15.50+32.16 s | 13.47 |
| RCHRochefort | 117.3 | 123 | 10:40:03.95+20.61 s | 10:40:18.46+35.12 s | 14.51 |
| MEMHMembach | 153.7 | 94 | 10:40:09.41+26.07 s | 10:40:28.51+45.17 s | 19.10 |
| MEMSMembach | 153.7 | 94 | 10:40:09.41+26.07 s | – | – |
| Dutch seismic network (KNMI)1 station | |||||
| HGNHeimansgroeve | 147.3 | 88 | 10:40:08.42+25.08 s | – | – |