DEURNE (NL)

Earthquake8 April 2003

Magnitude
2.0ML
Depth
16.0km ± 2.1
Belgian time
19:35:362003-04-08
UTC
17:35:362003-04-08

Main parameters

Magnitude and intensity

Two numbers often confused, with the values of this earthquake and of the Observatory’s catalogue.

Preparing the animation…

1Magnitude: the size of the earthquake

The magnitude (ML 2.0) measures the size of the earthquake at its source, from the amplitude of the waves recorded by seismographs: a single value for the whole earthquake. Since 1985, 83 % of the 3,122 earthquakes with a magnitude in the Observatory’s catalogue have a smaller one.

Animation drawn from the page and the Observatory’s catalogue (tectonic earthquakes since 1985, ML or MW magnitudes); short descriptions of the European Macroseismic Scale EMS-98.

Date and time2003-04-08 17:35:36 UTC
2003-04-08 19:35:36 Belgian time
MagnitudeML 2.0
Epicentral coordinates51.432° N, 5.870° E
Uncertainty ± 1.6 km
Depth of hypocenter16.0 ± 2.1 km
Event IDROB 2289

Data source : ROB (Royal Observatory of Belgium)
Last update : 2009-05-30 18:17:43 Belgian time

Location map

Where and when the earthquake began

The focus, the epicentre and their uncertainties, with this earthquake’s values.

Preparing the animation…

1Focus and epicentre

An earthquake starts at depth, at the focus (or hypocentre): here 16 km below the surface. The point on the surface right above it is the epicentre (51.432° N, 5.870° E), the one the map shows.

Values from the page and the Observatory’s catalogue (tectonic earthquakes since 1985).

  • Epicentre
  • Station that recorded the event

Seismic activity in the area

Known earthquakes around the epicentre, from the catalogue of the Royal Observatory of Belgium.

Within 10 km of the epicentre

One other earthquake in the catalogue, in 1932.

Latest earthquakes before this one

DatePlaceMagnitudeIntensityDistance km
1932-11-23HELMOND-MEYEL (N)––8.1

Largest known earthquakes

DatePlaceMagnitudeIntensityDistance km
2003-04-08This earthquakeML 2.0––

Nearest beyond 10 km

DatePlaceMagnitudeIntensityDistance km
1997-07-26EarthquakeML 2.4–11.2
2025-06-27SOMEREN (NL)ML 1.3–13.3
1992-04-14? SOMEREN (NL)––15.2
2018-09-03HORST AAN DE MAAS (NL)ML 1.8–16.5
2007-05-21VENLO (NL)ML 0.9–18.2
Notes and method

Tectonic and induced earthquakes from the Observatory’s catalogue, suspected ones included; quarry blasts, explosions and other events are not counted. Epicentral distances on the WGS84 ellipsoid.

Municipality: 2025 municipal boundaries (Statbel), applied to every earthquake, including those before the merger of municipalities. For an epicentre outside Belgium, only the circular area is given. Each earthquake’s name is the catalogue’s: it may refer to a place near the epicentre.

Magnitude: the one given on each earthquake’s page (ML preferably, otherwise MW or MS); magnitudes of different types are compared as they are.

The epicentres of historical earthquakes are only known to within a few kilometres, sometimes more: whether they fall in the area is indicative. Small earthquakes have only been recorded as the station network grew: the area’s older earthquakes are mostly the largest ones, and recent activity looks more frequent.

When the area holds fewer than 5 other earthquakes, the nearest ones beyond 10 km are listed too, up to 100 km. Sequences (aftershocks, swarms) take a single row there, that of their largest earthquake: an earthquake joins a sequence if it occurs at most 7 days after the previous one and within 5 km of the first.

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
15
Epicentral distance
63.2 – 171.1km
Mean velocity, P wave
6.1km/s
Mean velocity, S wave
3.6km/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. Hypocenter at a depth of 16.0 km. P wave: 9 measurements, root-mean-square deviation 0.58 s. S wave: 10 measurements, root-mean-square deviation 0.56 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.

Table of measurements

Station measurements

P- and S-wave arrivals and ground displacement measured at each station. Click a column heading to change the order.

km°UTCUTCsnm
Belgian seismic network (Royal Observatory of Belgium)5 stations
EBNEben-Emael71.919117:35:48.21+12.04 s17:35:57.12+20.95 s8.91–
MEMBMembach92.117417:35:51.75+15.58 s17:36:02.94+26.77 s11.19–
HEYHeyd121.519017:35:56.02+19.85 s–––
RCHRochefort149.119817:35:59.69+23.52 s17:36:16.74+40.57 s17.0517.0
KLBKalborn149.117317:36:00.60+24.43 s17:36:18.07+41.90 s17.4715.1
Bensberg seismic network (University of Cologne, Germany)6 stations
KLLKalltalsperre92.716017:35:51.20+15.03 s17:36:03.12+26.95 s11.92–
BNSBensberg105.1119–17:36:06.65+30.48 s––
HOBHohbusch113.811517:35:55.32+19.15 s17:36:08.80+32.63 s13.48–
STBSteinbachtalsperre115.414317:35:55.39+19.22 s17:36:09.25+33.08 s13.86–
HILHillesheim139.0156–17:36:14.71+38.54 s––
BGGBurg Eltz171.114217:36:03.34+27.17 s17:36:21.81+45.64 s18.47–
Dutch seismic network (KNMI)4 stations
VKBValkenburg63.218517:35:47.65+11.48 s17:35:54.34+18.17 s6.69–
CHAChaam67.027717:35:48.87+12.70 s17:35:55.44+19.27 s6.57–
HGNHeimansgroeve74.417717:35:48.89+12.72 s17:35:57.34+21.17 s8.45–
WTSBWinterswijk New87.54717:35:50.08+13.91 s17:35:59.81+23.64 s9.73–
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