Land;
and;
Resources;
College,;
China;
West;
Normal;
University,Nanchong;
637002,;
Sichuan,;
China;
Institute;
of;
Mountain;
Hazards;
and;
Environment,;
Chinese;
Academyof;
Sciences,;
Chengdu;
610041,;
Sichuan,;
China;
College;
of;
Architecture;
and;
Environment,;
Sichuan;
University,Chengdu;
610065,;
Sichuan,;
China;