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Seismograph expression: "The dishes in the cupboards clink and jingle"
Photo:
Fredrik von Erichsen / DPA
There was a slight earthquake near Aachen on Saturday morning.
It was noticed at 7:36 a.m. between Aachen and Roetgen, a municipality on the border with Belgium, wrote the Geological Service of North Rhine-Westphalia on its website.
The strength was reportedly 2.8 on the Richter scale.
The quake occurred at a depth of about ten kilometers.
"The earthquake was clearly felt in the surrounding towns," said the geological service.
There were numerous reports from citizens of Roetgen, Stolberg, Breinig and Aachen.
Building damage is not to be expected in earthquakes of this magnitude, said Klaus Lehmann, head of the state earthquake service.
Such a quake occurs in the Lower Rhine Bay about once a year.
With a tremor with a magnitude of 2.8 you can feel a powerful shock: »So that you feel moved in your bed.
Or the dishes in the cupboards clink and jingle.
Light parts on the table can vibrate and move.
All of that can happen. "
Earthquake strengths
The Richter scale up arrow down
The strength of an earthquake is described using the
Richter scale
and other scales.
The specified value, the
magnitude
, characterizes the released energy.
The maximum
amplitudes
(i.e. the deflections of the needle) that would have been generated by earthquakes 100 km away are determined by
means of
seismographs
.
The
decadic logarithm of
the measured maximum amplitudes gives the magnitude.
Increasing the magnitude by 1 means a 33 times higher energy release - an earthquake with magnitude 5.0 is 33 times as strong as one with magnitude 4.0.
The scale was developed in 1935 by
Charles Francis Richter
and
Beno Gutenberg
at the California Institute of Technology.
Strictly speaking, however, earthquake strengths are now given on the
moment magnitude scale
.
In addition to the energy, it also takes into account the size of the broken rock.
The fracture surface can be calculated from the earthquake measurements of many seismographs.
The Impact Up Arrow Down Arrow
The
typical effects of earthquakes
near the
epicenter
can be roughly
described as follows:
- Strength 1-2: only detectable by instruments
- Strength 3: rarely felt near the epicenter
- Strength 4-5: 30 kilometers around the center noticeable, slight damage
- Strength 6: moderate earthquake, deaths and severe damage in densely populated regions
- Strength 7: strong tremor that can lead to disasters
- Strength 8: large earthquake
Every year around the world, around 50,000 earthquakes with a magnitude of three to four, 800 with a magnitude of five or six and an average of one large earthquake occur.
The strongest earthquake recorded on earth had a magnitude of 9.5 and
occurred in Chile in 1960
.
Germany is in the middle of the Eurasian Plate, plate borders are far away here - and yet the ground keeps shaking.
The reason are breaks and weak zones in the subsurface, which can cause problems.
According to the Federal Office for Civil Protection and Disaster Aid (BBK), the area west of Cologne has a relatively high earthquake hazard by German standards.
The tremors that were registered in April 1992 in the border region between Germany and the Netherlands have shown that tremors can also cause greater damage in this country.
The so-called earthquake in Roermond had a magnitude of 5.9 at that time and caused damage in the three-digit million range.
Icon: The mirror
wit / dpa
