Aizawl, April 20: Mizoram was rocked by an earthquake measuring 4.3 on the richter scale around 1910 hrs yesterday. Dr H Lallenmawia, joint director of Mizorams geology and mining department quoting the seismological observatory reading here, said the epicentre of the quake was about 10 km north of Kolasib, in northern Mizoram near the Assam border.