A digger scraping damaged tarseal from River Road in Richmond. A portaloo sits on the side of the road. The photographer comments, "Road repairs. River Rd, Richmond, looking west".
Damage to River Road in Richmond. The river bank has slumped towards the river, opening up a large crack along the side of the road. The photographer comments, "Lateral spreading in River Rd".
Silt-laden water flows into the Avon River. The photographer comments, "Corner River Rd, Banks Ave, Dallington Tce. Dirty water from Dudley Creek meets the Avon".
A digger scraping damaged tarseal from River Road in Richmond. The photographer comments, "Road repairs".
A man photographs large cracks in River Road where the road has slumped towards the river. The photographer comments, "Cracking in River Rd. The Banks Ave/Dallington Tce end of our block is impassable".
Roading machinery parked on the side of River Road. The road is under repair, but has not yet been resealed. The photographer comments, "Looking east to Banks Ave-Dallington Tce. River Rd nearly ready for re-sealing. Over the next year, the road subsided and was repaired 3 or 4 times".
Residents walk along River Road past large cracks where the road has slumped towards the river. The photographer comments, "Lateral spreading cracks in River Rd; the land left of the crack moved towards the river. The Banks Ave/Dallington Tce end of our block is impassable".
A pile of tarseal scraped from the damaged River Road sits in front of a house. The photographer comments, "Road repairs and abandoned houses".
A Treetech Specialist Treecare Ltd truck on River Road in Richmond. The photographer comments, "Treetech did a lot of work making trees and power lines safe".
A pile of gravel and tarseal in front of a house in Richmond during repairs to River Road. The photographer comments, "Our house was becoming progressively more shattered with each aftershock".
A pile of gravel and tarseal in front of a house in Richmond. The photographer comments, "River Rd repairs. We weren't living in our house, we'd moved out after the September 2010 shake".
A portaloo sits outside a house on River Road. The road is under repair, and the tarmac has been removed leaving a gravel surface. The photographer comments, "Our old house was given a portaloo; I'm not sure why".
Damage to River Road in Richmond. The road is badly cracked and buckled, and is partly blocked off with road cones and warning tape. In the background is a truck carrying more road cones and signs. The photographer comments, "Major slumps and cracks along River Rd. Near 381 River Rd, looking towards the Banks Ave - Dallington Terrace corner".
Damage to River Road in Richmond. The road is badly cracked and has slumped towards the river. Road cones and warning tape block off the road to vehicles. The photographer comments, "The end of River Rd, at the corner of Banks Ave-McBratneys Rd-Dallington Tce. Morons in 4WDs kept wanting to drive through here".
We examined the stratigraphy of alluvial fans formed at the steep range front of the Southern Alps at Te Taho, on the north bank of the Whataroa River in central West Coast, South Island, New Zealand. The range front coincides with the Alpine Fault, an Australian-Pacific plate boundary fault, which produces regular earthquakes. Our study of range front fans revealed aggradation at 100- to 300-year intervals. Radiocarbon ages and soil residence times (SRTs) estimated by a quantitative profile development index allowed us to elucidate the characteristics of four episodes of aggradation since 1000 CE. We postulate a repeating mode of fan behaviour (fan response cycle [FRC]) linked to earthquake cycles via earthquake-triggered landslides. FRCs are characterised by short response time (aggradation followed by incision) and a long phase when channels are entrenched and fan surfaces are stable (persistence time). Currently, the Te Taho and Whataroa River fans are in the latter phase. The four episodes of fan building we determined from an OxCal sequence model correlate to Alpine Fault earthquakes (or other subsidiary events) and support prior landscape evolution studies indicating ≥M7.5 earthquakes as the main driver of episodic sedimentation. Our findings are consistent with other historic non-earthquake events on the West Coast but indicate faster responses than other earthquake sites in New Zealand and elsewhere where rainfall and stream gradients (the basis for stream power) are lower. Judging from the thickness of fan deposits and the short response times, we conclude that pastoral farming (current land-use) on the fans and probably across much of the Whataroa River fan would be impossible for several decades after a major earthquake. The sustainability of regional tourism and agriculture is at risk, more so because of the vulnerability of the single through road in the region (State Highway 6).