LESSINES (BE)
Quarry blast22 January 2021
- Magnitude
- 1.8ML
- Depth
- –
- Belgian time
- 11:40:342021-01-22
- UTC
- 10:40:342021-01-22
Main parameters
| Date and time | 2021-01-22 10:40:34 UTC 2021-01-22 11:40:34 Belgian time |
|---|---|
| Magnitude | ML 1.8 |
| Epicentral coordinates | 50.705° N, 3.859° E Uncertainty ± 1.7 km |
| Event ID | ROB 11965 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-01-23 18:37:50 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
- 1.3 – 173.5km
- Mean velocity, P wave
- 5.6km/s
- Mean velocity, S wave
- 3.4km/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: 10 measurements, root-mean-square deviation 0.42 s. S wave: 6 measurements, root-mean-square deviation 0.11 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 | 1.3 | 299 | 10:40:34.22+0.07 s | 10:40:34.44+0.29 s | 0.22 |
| SKQSteenkerque | 16.8 | 112 | 10:40:36.87+2.72 s | 10:40:39.06+4.91 s | 2.19 |
| RQRRonquières | 28.1 | 113 | 10:40:38.80+4.65 s | – | – |
| BRQBracquegnies | 31.7 | 142 | 10:40:39.93+5.78 s | – | – |
| BOUBougnies | 35.7 | 170 | 10:40:40.39+6.24 s | – | – |
| UCCBUccle | 36.8 | 74 | 10:40:40.87+6.72 s | – | – |
| DOUDourbes | 85.7 | 142 | 10:40:49.58+15.43 s | 10:40:59.36+25.21 s | 9.78 |
| GESGesves | 94.0 | 112 | 10:40:51.59+17.44 s | 10:41:01.96+27.81 s | 10.37 |
| CLAClavier | 107.1 | 107 | 10:40:53.19+19.04 s | 10:41:06.05+31.90 s | 12.86 |
| RCHRochefort | 114.9 | 122 | 10:40:53.60+19.45 s | 10:41:08.32+34.17 s | 14.72 |
| MEMHMembach | 152.5 | 93 | 10:40:59.89+25.74 s | 10:41:19.08+44.93 s | 19.19 |
| KLBKalborn | 173.5 | 112 | 10:41:02.99+28.84 s | 10:41:23.66+49.51 s | 20.67 |
| Dutch seismic network (KNMI)1 station | |||||
| HGNHeimansgroeve | 146.5 | 87 | 10:40:59.02+24.87 s | – | – |