Abstract: 

The May 12, 2008 Wenchuan, China Earthquake was one of the most severe natural disasters in the recent history of China. The earthquake resulted in about 90,000 fatalities, 370,000 injuries, 4.8 million homeless individuals, and $100 billion in direct economic losses.   While much of the attention has focused on the enormous loss of life and poor structural performance, there are other important aspects that have broad implications:

1. The earthquake sequence was a rare event with apparent recurrence interval estimated in the range of 2000-10,000 years (Burchfiel et al., GSA Today, July, 2008).
2. At least two major subparallel reverse faults moved, more or less simultaneously, over a distance of more than 100 km, with the overall zone of faulting in excess of 270 km in length.
3. The causative reverse faults are very steeply dipping, 60 to 70 degrees, and as such represent an as yet undocumented style of faulting in terms of surface rupture characteristics and associated ground motions.  In particular, there is strong evidence for significant short period ground motions on the downthrown side of the fault zone in the Sichuan Basin.
4. The earthquake generated hundreds of large and very large landslides and dozens of landslide dams on a scale that is without recent precedent.

The presentation will focus on observations made during a reconnaissance trip to the epicentral region, including structural performance, style of faulting, landslides, and apparent ground motions.