WELLINGTON, Jan. 12 (Xinhua) -- An earthquake measuring 4.6 on the Richter scale hit the top of New Zealand's South Island on Monday morning but caused no casualties or damages.

    New Zealand's Institute of Geological and Nuclear Science (GNS Science) said the earthquake occurred at 4:50 a.m. local time (1550 GMT Sunday) and was centered about 40 km south of Nelson at a depth of 100 km.

    It would have been felt in the north of the South Island.