VIROINVAL (BE)
Quarry blast20 April 2021
- Magnitude
- 1.4ML
- Depth
- –
- Belgian time
- 12:30:442021-04-20
- UTC
- 10:30:442021-04-20
Main parameters
| Date and time | 2021-04-20 10:30:44 UTC 2021-04-20 12:30:44 Belgian time |
|---|---|
| Magnitude | ML 1.4 |
| Epicentral coordinates | 50.093° N, 4.591° E Uncertainty ± 7.6 km |
| Event ID | ROB 13240 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-04-23 18:02:45 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
- 5
- Epicentral distance
- 0.4 – 121.1km
- Mean velocity, P wave
- 3.0km/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: 4 measurements, root-mean-square deviation 0.52 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)4 stations | |||||
| DOUDourbes | 0.4 | 52 | 10:30:39.69−4.52 s | 10:30:41.63−2.58 s | 1.94 |
| MRDMaredsous | 26.5 | 28 | 10:30:48.34+4.13 s | – | – |
| RCHRochefort | 46.0 | 81 | 10:30:54.02+9.81 s | – | – |
| GESGesves | 48.1 | 47 | 10:30:56.15+11.94 s | – | – |
| Dutch seismic network (KNMI)1 station | |||||
| HGNHeimansgroeve | 121.1 | 51 | 10:31:00.59+16.38 s | 10:31:16.75+32.54 s | 16.16 |