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).
Note the innovative use of hay bales on the left side of the image.
Christchurch CBD New Zealand 31 August 2011
Christchurch CBD New Zealand 31 August 2011
Christchurch CBD New Zealand 31 August 2011
Christchurch CBD New Zealand 31 August 2011
Christchurch CBD New Zealand 31 August 2011
Christchurch CBD New Zealand 31 August 2011
Christchurch CBD New Zealand 31 August 2011
Christchurch CBD New Zealand 31 August 2011
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Canterbury Earthquake 04/09/10 Christchurch New Zealand
Part the First Movember is upon us once again, and to celebrate Undershaved Overgrown Archaeology brings to you a brief history of facial hair in Aotearoa. Movember is all about men’s health, and we’ve previously covered health in the blog … Continue reading →
An article from the Media Studies Journal of Aotearoa New Zealand Volume 14, Number 1. The article is titled, "Heroic Radio: a study of radio responses in the immediate aftermath of the September 2010 Earthquake in Christchurch, New Zealand". It was written by Ruth Zanker.
Christchurch CBD New Zealand 31 August 2011
Canterbury Earthquake 04/09/10 Christchurch New Zealand
A PDF copy of pages 300-301 of the book Christchurch: The Transitional City Pt IV. The pages document the transitional project 'Coffee Zone Mini Park'. Photos with permission from Greening the Rubble