N: auto 0cm" class=MsoNormal>n’,’serif’" lang=EN-US>///nChDivSummary name="EnDivSummary">By analyzing the aftershock data of Tangshan earthquake 1976 with higher category of epicentral location accuracy, a clear distribution pattern of three bands of aftershocks trending NE, NWW, and NW respectively has been identified. The analysis explains that the aftershock bands have revealed the three rupture planes of strong events with magnitude 7.8, 7.1 and 6.9, respectively during the sequence. It indicates that the above pattern is related to the source and NE, NWW, and NW trending fault zones. In summary, the source is located in the cross-area of the three fault zones, and the rupture planes of the three strong events located in the source should be regarded as the locked segments on the three fault zones.namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />