Magnitudes and related topics relevant to hazard input

Domenico Di Giacomo
International Seismological Centre, Thatcham (UK)

One of the most important activity in seismology is to characterize the earthquake source. In doing so, seismologists usually compute hypocentre locations, estimate magnitudes and various source parameters with the intent of assessing the potential impact of earthquakes in a given area. In turn, earthquake source parameters are often used as input for hazard studies at different scales and for investigating patterns of the seismicity of the Earth. In this contribution I intend to provide an overview of the evolution of standard seismological practice since instrumental recording began at the beginning of the last century, and discuss recent developments in terms of earthquake catalogues, magnitude related problems and associated source characteristics that are essential input for improved seismic hazard studies.