TOURNAI (BE)
Quarry blast9 July 2018
- Magnitude
- 1.9ML
- Depth
- –
- Belgian time
- 12:31:362018-07-09
- UTC
- 10:31:362018-07-09
Main parameters
| Date and time | 2018-07-09 10:31:36 UTC 2018-07-09 12:31:36 Belgian time |
|---|---|
| Magnitude | ML 1.9 |
| Epicentral coordinates | 50.612° N, 3.350° E Uncertainty ± 3.8 km |
| Event ID | ROB 6920 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2018-07-11 11:03:58 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
- 11
- Epicentral distance
- 49.0 – 204.4km
- Mean velocity, P wave
- 6.1km/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: 6 measurements, root-mean-square deviation 0.35 s. S wave: 5 measurements, root-mean-square deviation 0.57 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)11 stations | |||||
| BOUBougnies | 49.0 | 120 | 10:31:45.13+8.81 s | 10:31:51.43+15.11 s | 6.30 |
| SKQSteenkerque | 51.8 | 85 | 10:31:44.66+8.34 s | 10:31:51.57+15.25 s | 6.91 |
| BRQBracquegnies | 57.6 | 104 | 10:31:46.04+9.72 s | – | – |
| RQRRonquières | 61.9 | 90 | 10:31:46.40+10.08 s | 10:31:55.35+19.03 s | 8.95 |
| DOUDourbes | 105.6 | 123 | 10:31:54.26+17.94 s | 10:32:07.10+30.78 s | 12.84 |
| MRDMaredsous | 106.4 | 108 | 10:31:53.82+17.50 s | 10:32:08.89+32.57 s | 15.07 |
| GESGesves | 125.8 | 101 | 10:31:57.38+21.06 s | – | – |
| MOLTMol | 139.2 | 61 | 10:32:00.18+23.86 s | – | – |
| OPTOpitter | 170.2 | 70 | 10:32:04.34+28.02 s | – | – |
| HOUHouvegnez | 190.6 | 98 | 10:32:07.95+31.63 s | – | – |
| KLBKalborn | 204.4 | 105 | 10:32:08.97+32.65 s | 10:32:32.94+56.62 s | 23.97 |