Magnitude M w in metropolitan France
- 118 Downloads
The recent seismicity catalogue of metropolitan France Sismicité Instrumentale de l’Hexagone (SI-Hex) covers the period 1962–2009. It is the outcome of a multipartner project conducted between 2010 and 2013. In this catalogue, moment magnitudes (M w) are mainly determined from short-period velocimetric records, the same records as those used by the Laboratoire de Détection Géophysique (LDG) for issuing local magnitudes (M L) since 1962. Two distinct procedures are used, whether M L-LDG is larger or smaller than 4. For M L-LDG >4, M w is computed by fitting the coda-wave amplitude on the raw records. Station corrections and regional properties of coda-wave attenuation are taken into account in the computations. For M L-LDG ≤4, M w is converted from M L-LDG through linear regression rules. In the smallest magnitude range M L-LDG <3.1, special attention is paid to the non-unity slope of the relation between the local magnitudes and M w. All M w determined during the SI-Hex project is calibrated according to reference M w of recent events. As for some small events, no M L-LDG has been determined; local magnitudes issued by other French networks or LDG duration magnitude (M D) are first converted into M L-LDG before applying the conversion rules. This paper shows how the different sources of information and the different magnitude ranges are combined in order to determine an unbiased set of M w for the whole 38,027 events of the catalogue.
KeywordsEarthquake Magnitude Seismicity Seismic hazard France
The SI-Hex project has been conducted thanks to the contribution of the French Ministry of Ecology, Sustainable Development and Energy (MEDDE), together with CNRS, six universities and CEA (conventions no. 0007147 and no. 2100474508). The coda method for magnitude was developed by Marylin Denieul (Ph-D grant linked to the SIGMA/EDF research program). A large part of the material presented in this paper is extracted from the SI-Hex MEDDE final reports (2013).
- Bakun W (1984) Seismic moments, local magnitudes, and coda-duration magnitudes for earthquakes in Central California. B Seismol Soc Am 74:439–458Google Scholar
- Bethmann F, Deichmann N, Mai PM (2011) Scaling relations of local magnitude versus moment magnitude for sequences of similar earthquakes in Switzerland. B Seismol Soc Am 101:515–534Google Scholar
- Campillo M, Plantet J-L, Bouchon M (1985) Frequency-dependent attenuation in the crust beneath Central France from Lg waves: data analysis and numerical modeling. B Seismol Soc Am 75:1395–1411Google Scholar
- Draper NR, Smith H (1981) Applied regression analysis. John Wiley & Sons, New YorkGoogle Scholar
- Giardini D, Woessner J, Danciu L et al (2013) Seismic Hazard Harmonization in Europe (SHARE): doi: 10.12686/SED-00000001-SHARE
- Perrot J, Arroucau P, Guilbert J, Déverchère J, Mazabraud Y, Rolet J, Mocquet A, Mousseau M, Matias L (2005) Analysis of the Mw 4.3 Lorient earthquake sequence: a multidisciplinary approach to the geodynamics of the Armorican Massif, westernmost France. Geophys J Int 162:935–950. doi: 10.1111/j.1365-246X.2005.02706.x Corrigendum, 163, 1136–1136
- Rautian T G, Khalturin VI (1978) The use of the coda for determination of the earthquake source spectrum. Bull Seism Soc Am 68:923–948Google Scholar
- Rovida A, Camassi R, Gasperini P, Stucchi M (2011) CPTI11, the 2011 version of the parametric catalogue of Italian earthquakes. http://emidius.mi.ingv.it/CPTI. Accessed 14 April 2016
- SI-Hex (2013) Sismicité Instrumental de l’Hexagone 1962–2009, rapport final. http://eost.unistra.fr. Accessed … 2016.