The first of the temblors, measuring 4.4 on the open-ended Richter scale, occurred at 1:10 p.m., with the epicenter located 35.5 km southeast of the CWB Chengkung seismic station in Taitung at a depth of 6.2 km under the ocean floor, the seismologists said. The second, measuring 4.1 on the Richter scale, struck at 3:44 p.m., with the epicenter located 12.2 km west of the CWB's Taitung seismic station at a depth of 8.1 km underground, they said.