LENS (BE)
Quarry blast18 March 2021
- Magnitude
- 1.4ML
- Depth
- 5.0km ± 4.3
- Belgian time
- 14:03:202021-03-18
- UTC
- 13:03:202021-03-18
Main parameters
| Date and time | 2021-03-18 13:03:20 UTC 2021-03-18 14:03:20 Belgian time |
|---|---|
| Magnitude | ML 1.4 |
| Epicentral coordinates | 50.583° N, 3.953° E Uncertainty ± 3.1 km |
| Depth of hypocenter | 5.0 ± 4.3 km |
| Event ID | ROB 12800 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-03-19 18:16:47 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
- 11.6 – 141.3km
- Mean velocity, P wave
- 5.5km/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. Hypocenter at a depth of 5.0 km. P wave: 8 measurements, root-mean-square deviation 0.39 s. S wave: 4 measurements, root-mean-square deviation 0.45 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 | |||||
| SKQSteenkerque | 11.6 | 51 | 13:03:22.38+2.33 s | 13:03:23.79+3.74 s | 1.41 |
| BRQBracquegnies | 17.2 | 131 | 13:03:22.05+2.00 s | – | – |
| RQRRonquières | 19.4 | 82 | 13:03:23.20+3.15 s | – | – |
| SNFSeneffe | 24.8 | 109 | 13:03:24.02+3.97 s | – | – |
| TGATangissart | 40.3 | 86 | 13:03:26.53+6.48 s | – | – |
| MRDMaredsous | 65.8 | 118 | 13:03:31.36+11.31 s | 13:03:38.70+18.65 s | 7.34 |
| DOUDourbes | 71.0 | 140 | 13:03:32.89+12.84 s | 13:03:41.27+21.22 s | 8.38 |
| GESGesves | 83.4 | 105 | 13:03:34.88+14.83 s | 13:03:44.73+24.68 s | 9.85 |
| Dutch seismic network (KNMI)1 station | |||||
| HGNHeimansgroeve | 141.3 | 81 | 13:03:43.95+23.90 s | 13:04:01.40+41.35 s | 17.45 |