How to get as many local strong ground motion data as possible is one of the important issues in earthquake disaster investigation.In this paper we studied two cases in the May 12

2008

Wenchuan earthquake

exploring the possibility of recovering strong ground motion parameters from public monitor- ing video which were deployed for security purposes.We used the video of the Ningqiang No.1 Middle School

Hanzhong

Shaanxi Province

and estimated that the felt local strong ground motion lasted 80～100 s.The ground motion started with weak motion

increased gradually

with the peak value appeared at about 40 s.We used the video of a bank in Dujiangyan

Sichuan Province

and estimated that the local ground motion acceleration was at least 0.14 g.