ANTWERPEN (BE)
Controlled explosion1 July 2018
- Magnitude
- 1.7ML
- Depth
- –
- Belgian time
- 19:00:232018-07-01
- UTC
- 17:00:232018-07-01
Main parameters
| Date and time | 2018-07-01 17:00:23 UTC 2018-07-01 19:00:23 Belgian time |
|---|---|
| Magnitude | ML 1.7 |
| Epicentral coordinates | 51.238° N, 4.423° E Uncertainty ± 5.5 km |
| Event ID | ROB 6830 |
Data source : ROB (Royal Observatory of Belgium)
Last update : 2018-07-05 14:14:50 Belgian time
Location map
- Epicentre
- Station that recorded the event
Macroseismic inquiry
Intensities derived from the answers to the online questionnaire “Did you feel an earthquake?”, grouped by municipality (former municipalities included). The map and the chart give the intensity of each municipality.
- Answers
- 16
- Municipalities
- 1
- Farthest municipality
- 3km · ANTWERPEN
- Countries
- Belgium
- I
- II
- III
- IV
- V
- VI
- VII+
- 3–4
- 5–9
- 10–19
- 20–49
- ≥ 50
- Epicentre
Answers by intensity
| Intensity | Answers | |
|---|---|---|
| I | 1 | |
| II | 0 | |
| III | 7 | |
| IV | 7 | |
| V | 1 | |
| Total | 16 |
Intensity against distance
- Intensity of the municipality (CII)
Warning: the intensities derived from the inquiry are raw, unverified data.
Notes and method
Intensity of a municipality or a cell (CII, Community Internet Intensity) is computed as follows:
- I if no answer reports that the earthquake was felt;
- II–IX computed from 3 answer(s) kept: CII = 3.40 ln(CWS) − 4.38 (Wald et al., 1999), applied to the weighted sum (CWS) of the mean indexes of the answers; at least II if felt, at most IX.
Answers kept (USGS method, as applied by the ROB): reliability of 80 or more, given on the ground floor up to the 4th floor (or unknown floor), without those more than two standard deviations from the mean. The “felt” index is weighted by the answer to “Did others nearby feel it?”.
Distribution by intensity: macroseismic intensity (MI) recorded for each answer.
Cells: 5 or 10 km squares of the Belgian Lambert 72 grid, each answer placed at its geocoded address or at the point it placed on the map, otherwise at the centre of its municipality. The positions of the answers are published only rounded to about 1 km, in “Arrival of the answers”. Grid cell method: Van Noten et al. (2017), Solid Earth 8, 453–477, doi:10.5194/se-8-453-2017.
Depth not determined: distances measured from the epicentre.
Answers read on 2026-11-09 09:53.
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
- 14
- Epicentral distance
- 46.4 – 148.7km
- Mean velocity, P wave
- 5.9km/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: 10 measurements, root-mean-square deviation 0.87 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)14 stations | |||||
| MOLTMol | 46.4 | 93 | 17:00:31.54+8.35 s | – | – |
| SKQSteenkerque | 69.8 | 200 | 17:00:34.52+11.33 s | – | – |
| LESLessines | 71.3 | 215 | 17:00:35.58+12.39 s | – | – |
| RQRRonquières | 71.6 | 191 | 17:00:36.01+12.82 s | – | – |
| OPTOpitter | 86.0 | 99 | 17:00:40.71+17.52 s | – | – |
| BRQBracquegnies | 86.6 | 194 | 17:00:38.46+15.27 s | – | – |
| BOUBougnies | 100.2 | 200 | 17:00:40.75+17.56 s | – | – |
| GESGesves | 105.8 | 153 | 17:00:41.57+18.38 s | – | – |
| MRDMaredsous | 106.9 | 167 | 17:00:41.00+17.81 s | – | – |
| CLAClavier | 110.2 | 145 | 17:00:42.43+19.24 s | – | – |
| DOUDourbes | 127.7 | 174 | 17:00:44.91+21.72 s | – | – |
| MEMSMembach | 131.7 | 121 | 17:00:45.31+22.12 s | – | – |
| MRGMont Rigi | 141.6 | 124 | 17:00:47.22+24.03 s | – | – |
| HOUHouvegnez | 148.7 | 131 | 17:00:47.68+24.49 s | – | – |