Since 2016, Waikato Regional Councils’s excellent coastal flooding simulator has shown present and potential future flooding due to sea level rise around the Coromandel Peninsula. Next month the coastline of the Hauraki Plains between Kaiaua and Kopu will be added to the simulator allowing more accurate assessment of coastal flood risk. Many people will be shocked at the potential extent of coastal flooding due to sea level riseRead More »
Brazil’s Worst Environmental Disaster and over 300 Dead
For the second time in three years, a mine tailings dam in Brazil holding millions of tons of mud and sludge has collapsed cascading its toxic contents into local towns, killing scores of people and devastating the local environment. The Waihi and nearby Waitekauri mining companies say their tailings dam are safe but might they too collapse in a large earthquake?Read More »
In an earlier blog, I questioned whether the tailings dams at Waihi are earthquake safe
I have now received the latest reports on hazard/earthquake risk for all tailings dams. The reports are perfunctory and/or rely on obsolete research. Waikato Regional Council has failed to properly regulate these critical structures. The reports have strengthened my opinion that a fully independent reassessment of seismic safety is urgently required.Read More »
The two tailings dams near Waihi are some of the largest structures in the country.
Should either of these dams fail in an earthquake, we could be facing potentially New Zealand’s worst ever environmental disaster, and loss of life and livelihoods on a significant scale.
Therefore it is perfectly reasonable to ask the question – would these structures withstand a large earthquake? The question is even more pertinent because –
- the Kaikoura quake unleashed thousands of huge landslides
- a new GNS Science report on the nearby Kerepehi fault suggests a 7.4 magnitude earthquake is possible near Waihi, and also estimates that the interval between large quakes is 1000 years rather than 6000-8000 years as previously assumed.
- the catastrophic failure of a tailings dam in Brazil in 2015 was due in part to a very small 2.6Mw quake acting as a triggering mechanism for the dam collapse
In my first post I noted that Thames Coromandel Council/Civil Defence had failed to take heed of a May 2016 GNS Science which documented a potentially greater earthquake risk to Thames from the Kerepehi fault.
Well it gets worse. An earlier GNS Science report of February 2014 has also gone unheeded by TCDC and Waikato Regional Council. This 2014 report suggests that even greater levels of damage to parts of the Thames Coromandel District could result from an earthquake in the offshore part of the fault in the Firth of Thames. Read More »