(S (S (NP (BASENP (NNS Seismologists)) (PP (IN at) (BASENP (NNP USGS)))) (VP (VBP have) (VP (VBN indicated) (SBAR (IN that) (S (BASENP (DT this) (NN earthquake)) (VP (VBZ is) (NP (BASENP (DT an) (NN aftershock)) (PP (IN of) (NP (BASENP (DT the) (NN 9.0) (NN earthquake)) (SBAR (WHNP (WDT which)) (S (VP (VBD had) (VP (VP (VP (VBN occurred) (ADVP (BASENP (RB just) (DT a) (JJ few) (NNS hours)) (RBR earlier))) (COMMA ,) (ADJP (NP (BASENP (NN 305) (NN km)) (PRN (LRB -LRB-) (BASENP (NN 190) (NNS miles)) (RRB -RRB-))) (JJ distant))) (COMMA ,) (PP (IN in) (NP (BASENP (DT the) (NNP Indian) (NNP Ocean)) (PP (IN near) (NP (BASENP (NNP Sumatra)) (COMMA ,) (BASENP (NNP Indonesia))))))))))))))))))) (PERIOD .))