Intensity attenuation in the Campania region, Southern Italy

M. B. Sørensen (1) , D. Stromeyer (1) , G. Grünthal (1)

1 Seismic Hazard and Risk Dynamics [GFZ Potsdam]

Ground motion prediction equations (GMPE) in terms of macroseismic intensity are a prerequisite for intensity-based shake maps and seismic hazard assessment and have the advantage of direct relation to earthquake damage and good data availability also for historical events. In this study, we derive GMPE for macroseismic intensity for the Campania region in southern Italy. This region is highly exposed to the seismic hazard related to the high seismicity with moderate- to large-magnitude earthquakes in the Appenninic belt. The relations are based on physical considerations and are easy to implement for the user. The uncertainties in earthquake source parameters are accounted for through a Monte Carlo approach and results are compared to those obtained through a standard regression scheme. One relation takes into account the finite dimensions of the fault plane and describes the site intensity as a function of Joyner–Boore distance. Additionally, a relation describing the intensity as a function of epicentral distance is derived for implementation in cases where the dimensions of the fault plane are unknown. The relations are based on an extensive dataset of macroseismic intensities for large earthquakes in the Campania region and are valid in the magnitude range = 6.3–7.0 for shallow crustal earthquakes. Results indicate that the uncertainties in earthquake source parameters are negligible in comparison to the spread in the intensity data. The GMPE provide a good overall fit to historical earthquakes in the region and can provide the intensities for a future earthquake within 1 intensity unit.

Mots clés: Campania region; Intensity data points; Earthquake early warning; Seismic hazard; Macroseismic intensity; Attenuation; Ground motion prediction

M. B. Sørensen, D. Stromeyer, G. Grünthal. Intensity attenuation in the Campania region, Southern Italy. Journal of Seismology, 2009, 14 (2), pp.209-223. ⟨10.1007/s10950-009-9162-2⟩. ⟨hal-00535494⟩