%0 Journal Article
%T A possible seismomagnetic precursor of the El Mayor-Cucapah earthquake (Mw 7.2) of April 4, 2010, Baja California, M¨¦xico
%A Fregoso-Becerra
%A Emilia
%A Garc¨ªa-Abdeslem
%A Juan
%J Geof¨ªsica internacional
%D 2011
%I Universidad Nacional Aut¨®noma de M¨¦xico
%X we describe a possible seismomagnetic precursor to the mw 7.2 earthquake of april 4, 2010, with epicenter nearby the sierras el mayor and cucapah in ne baja california, m¨¦xico, (el mayor-cucapah earthquake). we used total-field magnetic intensity data recorded on a temporal magnetic base station on the roof of the earth sciences division of cicese, in ensenada, baja california, m¨¦xico, and magnetic observatories at tucson, arizona, and fresno, california, usa. these data were recorded at a sampling rate of one minute from march 26 and until april 19, 2010. a comparison of these data let us verify that during the measurement period the three stations recorded similar variations of the geomagnetic field. our analysis is based upon a statistical measure that we call index of magnetic variation, which allows us to detect and quantify anomalous variations of the magnetic field from data of a single station. based upon the magnetic field data, we suggest that the proposed index of magnetic variation identifies a possible seismomagnetic event, which begins 40 minutes before the earthquake and has duration of about 3 hours, as well as anomalous behavior of the geomagnetic field caused by a geomagnetic storm beginning on april 5.
%K index of magnetic variation
%K seismomagnetic effect
%K el mayor-cucapah earthquake
%K baja california
%K m¨¦xico.
%U http://www.scielo.org.mx/scielo.php?script=sci_abstract&pid=S0016-71692011000200007&lng=en&nrm=iso&tlng=en