(S (S (NP (BASENP (NNP Antarctica) (POS 's)) (BASENP (JJS biggest) (NN earthquake))) (VP (VBD was) (NP (BASENP (DT a) (NN magnitude) (NN 8.1)) (SBAR (WHNP (WDT which)) (S (VP (VP (VBD occurred) (PP (IN on) (NP (BASENP (NNP March) (NN 25)) (COMMA ,) (BASENP (NN 1998))))) (PP (IN near) (NP (BASENP (DT the) (NNP Balleny) (NNPS Islands)) (PP (IN of) (BASENP (NNP Antarctica))))))))))) (PERIOD .))