Northern Central Europe is a slowly deforming, low-strain intraplate area. Nevertheless, there is evidence for neotectonic fault activity, as well as for historic and recent earthquakes. The current knowledge is that the tectonic activity is mainly concentrated at major WNW-ESE striking lithospheric structures, from north to south, the Sorgenfrei-Tornquist Zone, the southern and northern margins of the Ringkøbing Fyn high and at individual faults like the Osning thrust or the Harz boundary fault, with some recent earthquake activity in between, possibly at the Thor suture. The Ringkøbing-Fyn high is a region of thicker crust separating the northern from the southern Permian basin. The Sorgenfrei-Tornquist Zone, the Osning thrust and the Harz boundary fault are located at the northern and southern margin of the Central European Basin System, respectively and these are the two areas, where the Late Cretaceous inversion phase that is characteristic of northern Central Europe, had a very pronounced effect. The faults in these areas have in common that they penetrate large parts of the crust, partly down to the Moho. Therefore, they represent stress-sensitive, first-order lithospheric features, where past, present, and potentially future seismic events are manifested. Repeated reactivation of these structures might have caused large-scale fatigue processes that can have weakened the faults and made them prone to stress release and neotectonic movements and enhance the potential for a reactivation due to stress field changes induced by glacial isostatic adjustment (GIA). This has implications for the seismic hazard assessment of northern Central Europe.

Assessing seismic hazard in tectonically active intraplate regions with slow slip rates (<0.1 mm/yr) is particularly challenging, especially when such regions are densely populated and extensively anthropogenically modified. Fault activity often remains undetected due to long recurrence intervals, limited surface expressions, and widespread anthropogenic overprinting. The Lower Rhine Graben (LRG), part of the European Cenozoic Rift System, exemplifies these conditions. In addition to its current low to moderate seismicity, the LRG region has experienced damaging historical earthquakes (e.g., Düren 1756, M_L 6.4; Roermond 1992, M_L 5.9), underscoring its seismic potential.

In this context, we conducted five paleoseismic investigations within the LRG to access direct geological records of past surface-rupturing events and fault kinematics. We focused on its most seismically active and structurally segmented subregions: the Roer Valley Graben and the Erft Block. The investigated fault segments include the Feldbiss Fault, Sandgewand Fault, Birkesdorfer Fault, Rurrand Fault, and the Louise Sprung.

All sites provide evidence of Late Pleistocene to Holocene surface-rupturing events, with single-event displacements of up to 70 cm and estimated magnitudes up to M 6.3. The faults are characterized by steeply dipping planes (70 – 80°), pure dip-slip kinematics, low slip rates (< 0.03 mm/yr), and show indications of hydraulic activity. At the Rurrand Fault and Louise Sprung, we observed induced aseismic creep linked to groundwater extraction, highlighting the need to distinguish natural from anthropogenic deformation.

Our results demonstrate the seismic potential of these faults and underline the importance of integrating paleoseismic data into regional seismic hazard assessments.

The imposing Romanesque cathedral of Speyer (Upper Rhine Graben, Germany) was built as thr burial site of German emperors, consecrated in AD 1061. However, mere two decades later it was almost completely rebuilt, a very unusual step in the history of any church. We put forward the hypothesis that the cathedral was severely damaged by an earthquake making re-building necessary. We describe construction history, identify features of earthquke-induced damage, and describe engineering solutions to make the new building more resistant to seismic shaking. An intensity IX-X is assigned based on archeoseismological evidence. The AD 1080 earthquake, recorded in Mainz (ESI-2007 = VII-VIII), some 80 km to the north, was probably the culprit. We suggest to relocate the epicentre from the proximity of Mainz southward, towards Speyer, with an M6.5 magnitude. ShakeMap analysis supports lower intensity for Mainz and higher intensity for Speyer. Worms cathedral, located halfway between Mainz and Speyer, bears evidence for destructive earthquake with severely tilted walls, which necessitated the rebuilding of collapsed vaults. Damage to the choir and apsis are very similar to those of Speyer. Start of the construction is known to be some time before 1132-37 AD. Whether this was the same earthquake which damaged Speyer, needs further considerations. Archaeoseismology provides information about past earthquakes which lack proper historical documentation.

Carora is located in western Venezuela on the edge of the Carora Basin, on Quaternary sediments over Cretaceous and Tertiary rocks in a region with intermediate seismicity. Carora has experienced medium seismic damage (MCS= VII), such as in the M6.9 El Tocuyo earthquake (1950). Some potential seismic sources affecting Carora are Burbusay fault and the Mesa de Aregue fault, this one 20 km to the north.

Geophysical data obtained in Carora include ambient noise measurements which were analyzed using Rayleigh wave ellipticity curve inversion. Three seismic microzones were defined based on results from ReMi (Refraction Microtremor) and topographic analysis for Vs30 and depth determination (H) to a seismic basement with Vs > 1200 m/s. Microzone 1 corresponds to formations with Vs30 > 400 m/s (a Class C site) and H < 80 m. Microzone 2 comprises sediments with Vs30 of 200-400 m/s (a Class D site) and H < 110 m, and microzone 3 comprises sediments with Vs30 of 200-400 m/s (a Class D site) and H of 110-230 m.

Probabilistic Seismic Hazard Assessment (PHSA) was conducted based on the geographic location, Vs30, and basement depths. Faults and sectors of intermediate seismicity within a 2º radius (222 km) of the center of Carora were considered. Three NGA-2013-2014 attenuation relationships were used to calculate rock and site spectral responses at 21 structural periods, for 4 seismic return periods. Then site spectra were smoothed for engineering purpose. Results lead to specified spectra limited by 85% of building code values.

The Wiechert earthquake station in Göttingen is the oldest existing seismograph station in the world, recording earthquakes continuously since 1903. In 2003, the broadband seismometer station GTTG was installed as part of the German Regional Seismic Network (GRSN) in close vicinity of the old instruments.

An analysis of the recordings of regional earthquakes showed a strong amplification of the horizontal signals around 3 Hz. This finding indicates that softer surficial layers overlie the harder seismic bedrock at the site. In order to investigate and quantify this site effect in more detail, different geophysical measurements were performed.

Using 20 three-component sensors, H/V and Rayleigh wave ellipticity curves were obtained for each single sensor. Analyzing 2.5 hours of passive seismic array data, dispersion curves for Love and Rayleigh waves were retrieved.

The Mintrop ball, a steel sphere of about 4 tons, was dropped three times from a height of about 14 m to perform an active seismic experiment. Analyzing the signals as a refraction seismic measurement, a P-wave velocity of about 700 m/s was determined for the uppermost 12 m. Analyzing the array signals of the drops by appropriate methods, dispersion and ellipticity curves were also obtained.

The active and passive dispersion curves are in good agreement. An inversion of the measured curves indicates that a strong velocity contrast at a depth of about 55 m, where the S-wave velocity increases from about 600 to almost 2000 m/s, can explain the amplification peak at 3 Hz.