Figure 1: Epicentres of the catalogued earthquakes since 1000 A.C. until 2001 (after Grünthal, 2003). Data base from Grünthal and Wahlström (2003a, b).

The highest earthquake activity shows in the seismic zone of the Rhine area which extends northward up to the Cologne area and from there westward to the Dutch Limburg and to Belgium. A centre of seismicity within the Lower-Rhine region is the Aachen-Dueren area. Within the Mid-Rhine region the Coblenz area shows the highest earthquake activity. Within the Upper-Rhine area there are many centres of higher seismicity: The northern part (Karlsruhe-Mayence) of the Rhine-Graben has concentrations of seismicity at its northern and southern regions (area Rheinstetten-Rastatt). The southern part of the Rhine-Graben shows increased quake activity in the Strasbourg area as well as in its southern part. The quake zone of the Swabian Jura was activated by one of the heaviest earthquakes of Germany on November 16th 1911 with a magnitude of 6.1 and an I0 of VIII. In combination with the two significant disastrous earthquakes of 1943 and 1978 (Figure 2) (I0=VII-VIII) this locally narrow-bounded zone of seismicity released the biggest part of Germany's seismic energy of the 20th century by far.

A northern continuation of this seismic zone is observed up to Tuebingen. Concerning earthquakes, Baden-Württemberg is the most active state of Germany with additional seismic sources in Salgau, southwest Donaueschingen and in the Black Forest. Another quake area is located in Eastern Thuringia and Western Saxony and extends from the swarm quake area ("Vogtländisches Schwarmbebengebiet") to Gera and Leipzig. The heaviest earthquake of this area so far happened on March 3rd 1872 east of Gera with an intensity of VII. The quake swarms (called "Voigtländischen Bebenschwärme") with a recorded number of up to 10.000 quakes in 1903, 1908 and in winter 1985/87 reached maximum magnitudes of ML=4.7 and intensities of VI-VII. A seismic area of minor significance is the seismic zone between Nördlingen and Donauwörth, which produced earthquakes of intensity VII in 1769 and 1915. The rest of Germany is not completely free of seismic activity but shows very little quake activity, like e.g. the quake of Bielefeld in 1612 (Figure 3) that caused only minor damage.

The earthquakes in Germany occur in depths of 5-20km with a focus of seismic energy release in about 10km depth.

Figure 4: The seismicity of the Mediterranean and the northerly adjacent parts of Europe, data after Grünthal and Wahlström (2003, completed).

North of the Mediterranean the West-Alps as well as the southern parts of the East-Alps, including the transition zone to the Dinarides, exhibit a relatively high seismicity. North of the Alps the highest seismicity in continental Europe occurs on German terrain. In northern Europe the Norwegian shelf shows a remarkable earthquake activity. The north-western edge of Figure 5 illustrates the high accumulation of earthquakes along the Mid-Atlantic Ridge that also represents a plate boundary. The figure makes clear how this plate boundary crosses Iceland with an eastward bulge.

Figure 5: Europe's quake activity north of the Mediterranean, completed westwards until the Mid-Atlantic Ridge; after Grünthal and Wahlström (2003).

In Europe the effects of earthquakes can also reach catastrophic dimensions. Table 2 provides a list of the five most catastrophic earthquakes in European history. The Messina earthquake of 1908 is ranked first. A considerable part of the victims and damages of this earthquake as well as of the Lisbon earthquake in 1755 was due to a tsunami caused by the quake, i.e. simplified a water wave caused by an earthquake.