NORTH SEA
Controlled explosion30 April 2021
- Magnitude
- 1.8ML
- Depth
- –
- Belgian time
- 11:00:572021-04-30
- UTC
- 09:00:572021-04-30
Main parameters
| Date and time | 2021-04-30 09:00:57 UTC 2021-04-30 11:00:57 Belgian time |
|---|---|
| Magnitude | ML 1.8 |
| Epicentral coordinates | 51.514° N, 3.394° E Uncertainty ± 5.9 km |
| Event ID | ROB 13280 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2021-04-30 16:00:04 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
- 8
- Epicentral distance
- 44.2 – 173.0km
- Mean velocity, P wave
- 6.2km/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 0.16 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 | |||||
| OSTBOostende | 44.2 | 226 | 09:01:05.84+7.90 s | 09:01:11.16+13.22 s | 5.32 |
| UCCBUccle | 104.5 | 139 | 09:01:15.92+17.98 s | – | – |
| SKQSteenkerque | 107.6 | 153 | 09:01:16.07+18.13 s | 09:01:28.95+31.01 s | 12.88 |
| RQRRonquières | 116.6 | 150 | 09:01:17.45+19.51 s | – | – |
| DSLBDessel | 120.5 | 104 | 09:01:18.75+20.81 s | – | – |
| SNFSeneffe | 127.9 | 150 | 09:01:19.62+21.68 s | – | – |
| TGATangissart | 128.4 | 142 | 09:01:19.35+21.41 s | 09:01:34.95+37.01 s | 15.60 |
| GESGesves | 173.0 | 136 | 09:01:26.19+28.25 s | 09:01:46.53+48.59 s | 20.34 |