Japan's Meteorological Agency upgraded its assessment of the quake from magnitude 8.8 to 9.0. The quake was actually three very large earthquakes in quick succession, it said Sunday.

The scale of the disaster is huge and its effect on companies and the national economy is difficult to determine.

Several electronics companies have plants in the region and they've been offline since Friday.

Toshiba makes microprocessors and image sensors in the region and its factory has been without power most of the weekend, said Keisuke Ohmori, a spokesman for the Tokyo-based company.

"We don't know when we can resume production," he said.