Contour mapping of seismic areas by numerical filtering and geological implications

A method is described that makes possible the identification of the independent seismic units of a given area (Caputo and Postpischl, 1973 b). The seismic information is treated as a bidimensional signal disturbed by a certain background noise. The filtering of this noise makes it possible to delineate the seismic areas objectively. An indirect check on the method was made by estimating with respect to the various regions identified the a and /J parameters of the law Ny = a e~Py which gives the number of earthquakes with magnitude (intensity) greater than or equal to y

Le conoscenze attuali dei movimenti del suolo nell'area italiana. Proposte per un coordinamento delle ricerche in atto in considerazione delle nuove strumentazioni e tecniche operative.

The significance of monitoring crustal deformations related to variousgeophysical phenomena is pointed out; both classical geodetic methodsand modern spatial techniques are reviewed. The analysis of thestate of the art in Italy is carried out with particular concern to surveysin seismic and volcanic areas

Palaeoseismicity from karst sediments: the “Grotta del Cervo” cave case study (Central Italy)

Karst speleothems can be used for tectonic and palaeoseismic analyses; in particular, stalagmites can be treated as the records of a natural pendulum. Samples of stalagmites from the “Grotta del Cervo” and the “Grotta a Male” caves (Central Italy) have been dated using 14C and U/Th radiometric methods. The present paper shows the limits and validity of such methods for dating strong earthquakes of the past. In particular, radiometric 14C dating shows that the youngest general stalagmitic collapse observed inside the “Grotta del Cervo” cave must be related to the December 1456 earthquake of Central Italy