TY  - JOUR
A1  - Kübler, Simon
A1  - Friedrich, Anke M.
A1  - Gold, Ryan D.
A1  - Strecker, Manfred
T1  - Historical coseismic surface deformation of fluvial gravel deposits, Schafberg fault, Lower Rhine Graben, Germany
JF  - International journal of earth sciences
N2  - Intraplate earthquakes pose a significant seismic hazard in densely populated rift systems like the Lower Rhine Graben in Central Europe. While the locations of most faults in this region are well known, constraints on their seismogenic potential and earthquake recurrence are limited. In particular, the Holocene deformation history of active faults remains enigmatic. In an exposure excavated across the Schafberg fault in the southwestern Lower Rhine Graben, south of Untermaubach, in the epicentral region of the 1756 Duren earthquake (M (L) 6.2), we mapped a complex deformation zone in Holocene fluvial sediments. We document evidence for at least one paleoearthquake that resulted in vertical surface displacement of 1.2 +/- 0.2 m. The most recent earthquake is constrained to have occurred after 815 AD, and we have modeled three possible earthquake scenarios constraining the timing of the latest event. Coseismic deformation is characterized by vertical offset of sedimentary contacts distributed over a 10-m-wide central damage zone. Faults were identified where they fracture and offset pebbles in the vertically displaced gravel layers and fracture orientation is consistent with the orientation of the Schafberg fault. This study provides the first constraint on the most recent surface-rupturing earthquake on the Schafberg fault. We cannot rule out that this fault acted as the source of the 1756 Duren earthquake. Our study emphasizes the importance of, and the need for, paleoseismic studies in this and other intracontinental regions, in particular on faults with subtle geomorphic expression that would not typically be recognized as being potentially seismically active. Our study documents textural features in unconsolidated sediment that formed in response to coseismic rupturing of the underlying bedrock fault. We suggest that these features, e.g., abundant oriented transgranular fractures in their context, should be added to the list of criteria used to identify a fault as potentially active. Such information would result in an increase of the number of potentially active faults that contribute to seismic hazards of intracontinental regions.
KW  - Paleoseismology
KW  - Intraplate earthquakes
KW  - Earthquake hazards
KW  - Coseismic rupture
KW  - Central Europe
Y1  - 2018
U6  - https://doi.org/10.1007/s00531-017-1510-9
SN  - 1437-3254
SN  - 1437-3262
VL  - 107
IS  - 2
SP  - 571
EP  - 585
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Chen, Yen-Shin
A1  - Weatherill, Graeme
A1  - Pagani, Marco
A1  - Cotton, Fabrice
T1  - A transparent and data-driven global tectonic regionalization model for seismic hazard assessment
JF  - Geophysical journal international
N2  - A key concept that is common to many assumptions inherent within seismic hazard assessment is that of tectonic similarity. This recognizes that certain regions of the globe may display similar geophysical characteristics, such as in the attenuation of seismic waves, the magnitude scaling properties of seismogenic sources or the seismic coupling of the lithosphere. Previous attempts at tectonic regionalization, particularly within a seismic hazard assessment context, have often been based on expert judgements; in most of these cases, the process for delineating tectonic regions is neither reproducible nor consistent from location to location. In this work, the regionalization process is implemented in a scheme that is reproducible, comprehensible from a geophysical rationale, and revisable when new relevant data are published. A spatial classification-scheme is developed based on fuzzy logic, enabling the quantification of concepts that are approximate rather than precise. Using the proposed methodology, we obtain a transparent and data-driven global tectonic regionalization model for seismic hazard applications as well as the subjective probabilities (e.g. degree of being active/degree of being cratonic) that indicate the degree to which a site belongs in a tectonic category.
KW  - Fuzzy logic
KW  - Earthquake hazards
KW  - Seismicity and tectonic
Y1  - 2018
U6  - https://doi.org/10.1093/gji/ggy005
SN  - 0956-540X
SN  - 1365-246X
VL  - 213
IS  - 2
SP  - 1263
EP  - 1280
PB  - Oxford Univ. Press
CY  - Oxford
ER  -