Magnitude assessment of northwestern european earthquakes

Ambraseys, N. N.

doi:10.1002/eqe.4290130305

Cited by 32 publications

(10 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

Section: Discussionmentioning

confidence: 99%

“…Significant regional differences in the M,/ML relationship are to be expected, as shown by the differences between those for New Zealand, Californian and European earthquakes, apparently because of regional differences in M,, ML and mean focal depths. 6, From the mean orthogonal relationship between M , and ML for the New Zealand data, it was found that M , = M , at magnitude 6-06. This was quite similar to the M , = ML at 5.76 found for Californian data, but very different from the European value.…”

Section: Maximum Distance At Which Surface Waves Reportedmentioning

confidence: 97%

See 1 more Smart Citation

Magnitude reassessment of New Zealand earthquakes

Dowrick

1991

Earthq Engng Struct Dyn

View full text Add to dashboard Cite

SUMMARYThe surface-wave magnitudes of a selection of New Zealand earthquakes have been determined on a consistent basis using the 'Prague formula' and station corrections. The earthquakes range in magnitude from about 5 to 7.8, covering the instrumental period . Magnitudes for many of the earlier events had not been properly determined previously; and some significant discrepancies from the traditional magnitudes were found.The use of European station data (160" < D < 175") is important to New Zealand because of its geographical isolation. These distant data were found to ghe consistently slightly higher M, than closer stations, but could be used without bias through the station correction procedure. The relationship between M , and ML was found for 31 'shallow' New Zealand events and much of the scatter was explained as a function of depth. Significant differences in M J M , expressions from Europe and California were also found.The limited New Zealand data for M , and M , related well to Californian and global relationships with M,.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Maximum Distance At Which Surface Waves Reportedmentioning

confidence: 97%

Magnitude reassessment of New Zealand earthquakes

Dowrick

1991

Earthq Engng Struct Dyn

View full text Add to dashboard Cite

show abstract

“…The unknowns are C 1 and C 2 as part of the source term, b as part of the geometrical spreading term and c as part of the intrinsic attenuation term. Such formulation has already been used to develop intensity attenuation models and to compute magnitudes and depths of past earthquakes around the world (Ambraseys 1985;Levret et al 1994;Cecic et al 1996;Musson 1996;Bakun and Wentworth 1997;Hinzen and Oemish 2001;Bakun 2006;Bakun and Scotti 2006;Beauval et al 2010;Gasperini et al 2010;Musson and Cecic 2012;Gomez-Capera et al 2015).…”

Section: Intensity Prediction Equations (Ipes)mentioning

confidence: 99%

The French seismic CATalogue (FCAT-17)

Manchuel¹,

Traversa²,

Baumont³

et al. 2017

Bull Earthquake Eng

View full text Add to dashboard Cite

In regions that undergo low deformation rates, as is the case for metropolitan France (i.e. the part of France in Europe), the use of historical seismicity, in addition to instrumental data, is necessary when dealing with seismic hazard assessment. This paper presents the strategy adopted to develop a parametric earthquake catalogue using moment magnitude M w , as the reference magnitude scale to cover both instrumental and historical periods for metropolitan France. Work performed within the framework of the SiHex (SIsmicité de l'HEXagone) (Cara et al. Bull Soc Géol Fr 186:3-19, 2015. doi:10.2113 and SIGMA (SeIsmic Ground Motion Assessment; EDF-CEA-AREVA-ENEL) projects, respectively on instrumental and historical earthquakes, have been combined to produce the French seismic CATalogue, version 2017 (FCAT-17). The SiHex catalogue is composed of *40,000 natural earthquakes, for which the hypocentral location and M w magnitude are given. In the frame of the SIGMA research program, an integrated study has been realized on historical seismicity from intensity prediction equations (IPE) calibration in M w detailed in Baumont et al. (submitted) companion paper to their application to earthquakes of the SISFRANCE macroseismic database (BRGM, EDF, IRSN), through a dedicated strategy developed by Traversa et al. (Bull Earthq Eng, 2017. doi:10. 1007/s10518-017-0178-7) companion paper, to compute their M w magnitude and depth. Macroseismic data and epicentral location and intensity used both in IPE calibration and inversion process, are those of SISFRANCE without any revision. The inversion process allows the main macroseismic field specificities reported by SISFRANCE to be taken into 123Bull Earthquake Eng DOI 10.1007/s10518-017-0236-1 account with an exploration tree approach. It also allows capturing the epistemic uncertainties associated with macroseismic data and to IPEs selection. For events that exhibit a poorly constrained macroseismic field (mainly old, cross border or off-shore earthquakes), joint inversion of M w and depth is not possible, and depth needs to be fixed to calculate M w . Regional a priori depths have been defined for this purpose based on analysis of earthquakes with a well constrained macroseismic field where joint inversion of M w and depth is possible. As a result, 27% of SISFRANCE earthquake seismological parameters have been jointly inverted and for the other 73% M w has been calculated assuming a priori depths. The FCAT-17 catalogue is composed of the SIGMA historical parametric catalogue (magnitude range between 3.5 up to 7.0), covering from AD463 to 1965, and of the SiHex instrumental one, extending from 1965 to 2009. Historical part of the catalogue results from an automatic inversion of SISFRANCE data. A quality index is estimated for each historical earthquake according to the way the events are processed. All magnitudes are given in M w which makes this catalogue directly usable as an input for probabilistic or deterministic seismic hazard studies. Uncertainties on magnitude...

show abstract

“…Of these, 170 are 20th-century events for which surface-wave magnitudes were calculated using instrumental data. 54 The basic information used in this study to derive intensity-attenuation and magnitude-intensity relationships consists of 74 maps with three isoseismals and 40 maps with four isoseismals. Of the remaining, 19 maps have five, and 24 maps have only two isoseismals.…”

Section: The Datamentioning

confidence: 99%

Intensity‐attenuation and magnitude‐intensity relationships for northwest european earthquakes

Ambraseys

1985

Earthq Engng Struct Dyn

View full text Add to dashboard Cite

SUMMARYThis study shows that, for Northwest Europe, an intraplate region of subdued seismicity, a comparatively simple attenuation model is adequate to predict quite accurately the fall-off of intensity with distance. The analysis shows that focal depths determined from macroseismic data are confined in the upper 25 km, and that shallow shocks attenuate far more rapidly than deeper events. There is no evidence for a regional variation of the absorption coefficient, which, together with the coefficient of geometric spreading, is a function ofdepth. Also, the intensity factor b, which is usually taken to be equal to 3, is a variable and a function of the energy absorption at the epicentre. It is shown that magnitudes can be predicted accurately by use of one or preferably by more isoseismal radii calibrated against re-assessed instrumental magnitudes.

show abstract

Magnitude assessment of northwestern european earthquakes

Cited by 32 publications

References 14 publications

Magnitude reassessment of New Zealand earthquakes

Magnitude reassessment of New Zealand earthquakes

The French seismic CATalogue (FCAT-17)

Intensity‐attenuation and magnitude‐intensity relationships for northwest european earthquakes

Contact Info

Product

Resources

About