Frogs detects chinas earth quake

On 5th Chinese people in chishuwan province detected 1000's of frogs crossing the roads without any fear (see the pictures), the wondered why. On Monday, 12th of May, central China region recorded a catastrophic 7.8-magnitude quake. More than 10000 people dead. Chinas earth quake detection centers couldn't even issue a warning. This was observed in the case of tsunami also, some animals recorded showing strange behaviors hours before the catastrophe. Someone should do a research on frogs to find out how they detected the earth quake, could be really helpful in the future. Can animals detect natural disasters? no need to answer that question, lets find out how?