Die Erdbeben in Kandel/Südpfalz von 1880 und 1903

Re-evaluation of intensity and source parameters of the earthquakes in Kandel/Southern Palatinate in 1880 and 1903.

The earthquakes of 24 January 1880 and 22 March 1903 are the strongest seismic events known for the region of Southern Palatinate (Upper Rhine Graben, Germany). Regarding the increased geothermal activity the re-evaluation of the historic earthquakes is of general interest. The analysis of the historic literature reveals a maximum intensity I0 = V (EMS-98) for the 1880 earthquake and I0 = VI for the event of 1903. Thus, for both seismic events the maximum intensity was overestimated in recent bulletins by one half and one whole grade, respectively. As a consequence, this also led to an overestimation of the magnitudes. The remarkable difference in the radius of perceptibility of both earthquakes (49 km and 30 km, respectively) in combination with the newly assigned intensities allows to estimate the magnitude of the event in 1880 to ML 3.7 (MW 3.3) at a hypocentral depth of 14 km; for the 1903 event a magnitude of ML 3.9 (MW 3.6) results for a shallow source at 2.5 km. The epicentres were approximately 3 km N-NE of Kandel in 1880 and directly at Kandel in 1903.