Scaling properties of the spatio–temporal distribution of earthquakes: a multifractal approach applied to a Californian catalogue |
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| Authors: | C Godano P Tosi V Derubeis & P Augliera |
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| Institution: | 1 Osservatorio Vesuviano, Via Manzoni 249, 80123 Napoli, Italy. E-mail:;, Istituto Nazionale di Geofisica, Via di Vignamurata 605, 00143 Roma, Italy. E-mail:;;, GNDT –CNR c/o Universitádi Genova, Dipartimento Scienze della Terra, Viale Benedetto XV 5, 16132 Genova. E-mail: |
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| Abstract: | We study the spatio–temporal scaling properties of the NCSN California catalogue for the period 1975–1995 (about 137 000 events) using a multifractal approach. The study is based on a new method of declustering earthquake catalogues based on looking for independent events. This technique makes use of the properties of the multifractal distribution of the inter-event times. A comparison test between our method and the Gardner and Knopoff (GK hereafter) approach reveals that our method produces a catalogue of independent events (monofractal Poissonian catalogue), while the GK declustered catalogue remains multifractal. The main difference lies in the assumption that the events can be considered to be correlated at large distances. The spatial properties of the declustered catalogue reveal a distribution of epicentres that is more complex than the distribution for the complete catalogue. We suggest that such results are very similar to the scaling properties of fully developed turbulence. |
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| Keywords: | declustering independent events multifractal |
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