LESSINES (BE)
Quarry blast21 August 2020
- Magnitude
- 2.1ML
- Depth
- –
- Belgian time
- 11:40:172020-08-21
- UTC
- 09:40:172020-08-21
Main parameters
| Date and time | 2020-08-21 09:40:17 UTC 2020-08-21 11:40:17 Belgian time |
|---|---|
| Magnitude | ML 2.1 |
| Epicentral coordinates | 50.718° N, 3.851° E Uncertainty ± 2.7 km |
| Event ID | ROB 10725 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2020-08-21 13:25:46 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
- 10
- Epicentral distance
- 0.9 – 174.6km
- Mean velocity, P wave
- 5.4km/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: 7 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)9 stations | |||||
| LESLessines | 0.9 | 217 | 09:40:18.00+0.06 s | 09:40:18.28+0.34 s | 0.28 |
| SKQSteenkerque | 17.9 | 115 | 09:40:20.72+2.78 s | – | – |
| RQRRonquières | 29.2 | 115 | 09:40:22.58+4.64 s | – | – |
| BRQBracquegnies | 33.2 | 142 | 09:40:23.86+5.92 s | – | – |
| DOUDourbes | 87.2 | 142 | 09:40:33.19+15.25 s | – | – |
| GESGesves | 95.1 | 112 | 09:40:35.96+18.02 s | – | – |
| RCHRochefort | 116.1 | 122 | 09:40:38.72+20.78 s | 09:40:52.65+34.71 s | 13.93 |
| MEMHMembach | 153.1 | 94 | 09:40:43.62+25.68 s | 09:41:02.68+44.74 s | 19.06 |
| KLBKalborn | 174.6 | 112 | 09:40:47.34+29.40 s | 09:41:07.95+50.01 s | 20.61 |
| Dutch seismic network (KNMI)1 station | |||||
| HGNHeimansgroeve | 147.0 | 87 | 09:40:42.45+24.51 s | 09:41:01.02+43.08 s | 18.57 |