Experts call for action to prevent secondary disasters in Yunnan

Experts have been briefing the media on the reasons for the high number of casualties.

"This is the most serious earthquake in Yunnan since 2000. The hypocenter was shallow with a depth of just 12 kilometers. The population density in the affected areas is about 270 per square kilometer. The houses are basically wood and brick, and are not strong enough to resist the shock." said Chen Hong, deputy Director of Crustal Dynamics Institution, China Earthquake Administraion.

As of 2:00 pm Monday Beijing time, more than 450 aftershocks had been recorded. So far no aftershock of over 5-magnitude quake has been registered. But experts say there is still possibility that a 5-magnitude to 6-magnitude aftershock could strike.

And they warn aftershocks and secondary disasters could cause massive damage if preventative measures are not taken. Continual rain has been hampering rescue work. More rain is forecast in the coming three days, raising the risk of epidemics.