@article{fdi:010053105,
  title = {{SCARDEC} : a new technique for the rapid determination of seismic moment magnitude, focal mechanism and source time functions for large earthquakes using body-wave deconvolution},
  author = {{V}all{\'e}e, {M}artin and {C}harlety, {J}. and {F}erreira, {A}. {M}. {G}. and {D}elouis, {B}. and {V}ergoz, {J}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}ccurate and fast magnitude determination for large, shallow earthquakes is of key importance for post-seismic response and tsumami alert purposes. {W}hen no local real-time data are available, which is today the case for most subduction earthquakes, the first information comes from teleseismic body waves. {S}tandard body-wave methods give accurate magnitudes for earthquakes up to {M}-w = 7-7.5. {F}or larger earthquakes, the analysis is more complex, because of the non-validity of the point-source approximation and of the interaction between direct and surface-reflected phases. {T}he latter effect acts as a strong high-pass filter, which complicates the magnitude determination. {W}e here propose an automated deconvolutive approach, which does not impose any simplifying assumptions about the rupture process, thus being well adapted to large earthquakes. {W}e first determine the source duration based on the length of the high frequency (1-3 {H}z) signal content. {T}he deconvolution of synthetic double-couple point source signals-depending on the four earthquake parameters strike, dip, rake and depth-from the windowed real data body-wave signals (including {P}, {P}c{P}, {PP}, {SH} and {S}c{S} waves) gives the apparent source time function ({STF}). {W}e search the optimal combination of these four parameters that respects the physical features of any {STF}: causality, positivity and stability of the seismic moment at all stations. {O}nce this combination is retrieved, the integration of the {STF}s gives directly the moment magnitude. {W}e apply this new approach, referred as the {SCARDEC} method, to most of the major subduction earthquakes in the period 1990-2010. {M}agnitude differences between the {G}lobal {C}entroid {M}oment {T}ensor ({CMT}) and the {SCARDEC} method may reach 0.2, but values are found consistent if we take into account that the {G}lobal {CMT} solutions for large, shallow earthquakes suffer from a known trade-off between dip and seismic moment. {W}e show by modelling long-period surface waves of these events that the source parameters retrieved using the {SCARDEC} method explain the observed surface waves as well as the {G}lobal {CMT} parameters, thus confirming the existing trade-off. {F}or some well-instrumented earthquakes, our results are also supported by independent studies based on local geodetic or strong motion data. {T}his study is mainly focused on moment determination. {H}owever, the {SCARDEC} method also informs us about the focal mechanism and source depth, and can be a starting point to study systematically the complexity of the {STF}.},
  keywords = {{I}nverse theory ; {E}arthquake source observations ; {B}ody waves ; {S}urface ; waves and free oscillations ; {W}ave propagation ; {S}ubduction zone processes},
  booktitle = {},
  journal = {{G}eophysical {J}ournal {I}nternational},
  volume = {184},
  numero = {1},
  pages = {338--358},
  ISSN = {0956-540{X}},
  year = {2011},
  DOI = {10.1111/j.1365-246{X}.2010.04836.x},
  URL = {https://www.documentation.ird.fr/hor/fdi:010053105},
}