Philip Yong & Jiashun Yu, 7 Nov 2008
On Day 4, the NZSEE team travelled north west of Chengdu and headed towards the area of the main Beichuan-Ying Xiu fault, one of three faults associated with the Wenchuan Earthquake.
We passed through the city of Deyang, Mianzhu township to get to the main fault line,
stopping at a number of major landslide sites, quake lakes and landslide dams on the way. Most of the landslide dams that the team have seen were cleared including Yi Ba Dao landslide dam, estimated to be 60m high, formed the second largest quake lake after the earthquake. It posed the biggest risk post-quake due to the population downstream. We also stopped at a massive landslide at the village of Tien Chi, a landslide formed from the quake induced collapse of the jointed rock.
Qing Ping village within 10km of the main fault line suffered the effects of the Wenjiagou landslide. At the village, we had the opportunity to observe behaviour of a number of village houses at various stages of completion, as well as structural damage of a road bridge just outside the village.
We arrived at the main Beichuan-Ying Xiu fault not far from Qing Ping Village, with significant ground deformation, we also observed serious damage to a number of village houses, damage to bridge and power facilities in the area.
At the Pengxian-Guaxian fault, the fault at the western side of the main fault, the entire village and a bridge structure was destroyed. A control gate structure for an irrigation system across the river at the fault site, was observed to have survived the effects of the fault.
The last stop of the day was at Hanwang, a town ship of over 40,000 population, with its main industry being the production of power generating steam turbine. This township suffered severe structural damages to most of its buildings on the flat next to a river, with the town centre now completely sealed off. There are high rise buildings within the site of the steam turbine manufacturing company, located on higher ground, which have survived well.
A selection of photographs are appended.
|A landslide which blocked the river and cleared.||Massive rockslide at Tien Chi village, road cut through slide for access and a small quake lake formed.|
|View of rockslide towards the top of the mountain.||Yi Ba Dao landslide dam, 60m high, formed the second biggest quake.|
|Wenjiangou landslide, burying part of Qing Ping Village||Beichuan – Yin Xiu fault movement.|
|Severely damaged house near to main fault||Bridge outside Qing Ping Village: deck shifted sideway about 300 mm.|
|Pengxian-Guaxian fault, collapsed spans due to failure of some of the piers.||Control gate structure at Penxian-Guaxian fault|
|Hanwang hospital severely damaged.||Hanwang hospital building: damage to longitudinal brick walls|
Philip Yong & Jiashun Yu