AMW6.4earthquakeoccurredinL'Aquila,centralItalyat1:32:42(UTC),April6,2009.WequicklyobtainedthemomenttensorsolutionoftheearthquakebyinvertingthePwaveformsofbroadbandrecordingsfromtheglobalseismographicnetwork(GSN)stationsusingthequicktechniqueofmomenttensorinversion,andfurtherinferredthatthenodalplaneofstrike132°,dip53°andrake-103°istheseismogenicfault.