LESSINES (BE)
Quarry blast4 February 2020
- Magnitude
- 1.9ML
- Depth
- –
- Belgian time
- 12:41:232020-02-04
- UTC
- 11:41:232020-02-04
Main parameters
| Date and time | 2020-02-04 11:41:23 UTC 2020-02-04 12:41:23 Belgian time |
|---|---|
| Magnitude | ML 1.9 |
| Epicentral coordinates | 50.713° N, 3.861° E Uncertainty ± 4.0 km |
| Event ID | ROB 9235 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2020-02-04 14:34:58 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
- 1.3 – 152.4km
- 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: 6 measurements, root-mean-square deviation 0.79 s. S wave: 4 measurements, root-mean-square deviation 0.38 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 | 1.3 | 260 | 11:41:24.17+0.23 s | – | – |
| SKQSteenkerque | 17.1 | 115 | 11:41:26.83+2.89 s | 11:41:29.01+5.07 s | 2.18 |
| DOUDourbes | 86.3 | 142 | 11:41:39.46+15.52 s | 11:41:49.16+25.22 s | 9.70 |
| GESGesves | 94.3 | 112 | 11:41:42.16+18.22 s | 11:41:52.58+28.64 s | 10.42 |
| DSLBDessel | 102.4 | 55 | 11:41:40.97+17.03 s | 11:41:54.34+30.40 s | 13.37 |
| RCHRochefort | 115.2 | 122 | 11:41:44.00+20.06 s | – | – |
| MEMHMembach | 152.4 | 94 | 11:41:49.27+25.33 s | – | – |
| MEMSMembach | 152.4 | 94 | 11:41:49.35+25.41 s | – | – |
| Dutch seismic network (KNMI)1 station | |||||
| HGNHeimansgroeve | 146.3 | 87 | 11:41:48.61+24.67 s | – | – |