Taiwan is still suffering from strong aftershocks after Tuesday's 6.4 magnitude earthquake, which killed at least seven people.
On Wednesday, a strong 5.7 magnitude quake jolted the same spot as Tuesday's tremor, which was about 20 kilometers northeast of Hualien.
The second quake came as rescuers in the city are still desperately trying to search for dozens of people trapped inside buildings that are tilting or have already collapsed.
Details on how much damage Wednesday's tremor has added were not immediately available.