The map of earthquake intensity published by CEA after surveying 500,000 km2 of the affected area shows a maximum liedu of XI on the China Seismic Intensity Scale (CSIS), described as "very destructive" on the European Macroseismic Scale (EMS) from which CSIS drew reference. (USGS, using the Modified Mercalli intensity scale (CC), also placed maximum intensity at XI, "very disastrous".) Two south-west-north-east stripes of liedu XI are centered around Yingxiu, Wenchuan (the town closest to the epicenter of the main quake) and Beichuan (the town repeatedly struck by strong aftershocks including one registering MS 6.1 on Aug 1, 2008), both in Sichuan Province, occupying a total of 2,419 km2. The Yingxiu liedu-XI zone is about 66 km long and 20 km wide along Wenchuan–Dujiangyan–Pengzhou; the Beichuan liedu-XI zone is about 82 km long and 15 km wide along An County–Beichuan–Pingwu. The area with liedu X (comparable to X on EMS, "destructive" and X on MM, "disastrous") spans 3,144 km2. The area affected by earthquakes exceeding liedu VI totals 440,442 km2, occupying an oval 936 km long and 596 km wide, spanning three provinces and one autonomous region.
How did the USGS rate the earthquake?
very disastrous