risk. there have been numerous studies that have documented it. there's a historical record of repeated failures on the landslide that have gone all the way across the river. >> we've done everything we could to protect them. we've mitigated the landslide from 2006. there's been warnings and advance notifications of high risk for landslides. we've done everything we could. my heart goes out to all of these individuals. >> officials say they believe a small earthquake 12 days ago may have played a role in causing the disaster. a despair that's growing for family members searching for missing loved ones. more than 100 people are still reported missing and now we're hearing some of the frantic 911 calls made in the moments right after the slide hit. >> there's a mudslide and everythings's gone. the houses are gone. i got people here screaming for help. >> my neighbor's house and their neighbor's house has been completely taken out. it's collapsed on several of them, and they're trapped. >> president obama says that he has signed an emergency