NAMUR (BE)
Quarry blast20 July 2021
- Magnitude
- 1.5ML
- Depth
- –
- Belgian time
- 13:41:002021-07-20
- UTC
- 11:41:002021-07-20
Main parameters
| Date and time | 2021-07-20 11:41:00 UTC 2021-07-20 13:41:00 Belgian time |
|---|---|
| Magnitude | ML 1.5 |
| Epicentral coordinates | 50.503° N, 4.970° E Uncertainty ± 4.2 km |
| Event ID | ROB 14020 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-07-26 12:03:28 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
- 26.6 – 92.7km
- Mean velocity, P wave
- 5.8km/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: 5 measurements, root-mean-square deviation 0.38 s. S wave: 4 measurements, root-mean-square deviation 0.43 s.
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)5 stations | |||||
| MRDMaredsous | 26.6 | 213 | 11:41:04.69+4.18 s | 11:41:09.21+8.70 s | 4.52 |
| RCHRochefort | 42.8 | 155 | 11:41:07.69+7.18 s | 11:41:13.26+12.75 s | 5.57 |
| DOUDourbes | 52.7 | 211 | 11:41:10.08+9.57 s | 11:41:15.86+15.35 s | 5.78 |
| SKQSteenkerque | 65.1 | 285 | 11:41:11.35+10.84 s | 11:41:19.89+19.38 s | 8.54 |
| KLBKalborn | 92.7 | 118 | 11:41:16.92+16.41 s | – | – |