Taipei  - A Taiwan satellite recorded a sharp drop in ionospheric density above China's Sichuan Province before Monday's killer earthquake, verifying previous records that seismic activities affect ionospheric density, a newspaper said Friday.

The China Times said that Taiwan's Formosa-3 satellite recorded that in the six to 15 days before the May 12 earthquake in Sichuan, the ionospheric density in the atmosphere about 1,000 square kilometres around Wenchuan, epicentre of the quake, was 1.2 million electrically charged particles.

On May 11, the eve of the quake, the ionospheric density over Sichuan had dropped by half to 600,000 charged particles.

Formosa-3 was launched by the Taiwan National Space Organization in 2006.

Since then, Formosa-3 has recorded ionospheric density after 63 earthquakes measuring magnitude 5 or above on the Richter scale, revealing a sharp drop in ionosphere density in 70 per cent of these cases.

An earthquake measuring 7.9 on the Richter scale hit Sichuan County, south-east China, at 2:30 pm on May 12.

The quake has killed more than 20,000 people and destroyed 500,000 homes. (dpa)