New Zealand Volcanic Activity

New Zealand is pretty much just a giant volcano. I say that because in total there are 345 volcano's as reported by the Smithsonian Institution National Museum of Natural History Global Volcanism Program. There are so many in the area because of the type of plate boundary New Zealand lies on, which is a convergent subduction plate as I have stated in previous blog posts. Keep in mind the majority of these volcano's are not active and are submerged underwater, but even on the islands, there are quite a few. The Active and potentially active volcano's are permanently monitored 24/7; using techniques in geodesy, seismology, chemistry, and remote sensing. There are early volcanic unrest monitor systems in place that monitor seismic activity and early gas release. Another helpful tool used is volcanic hazard maps that show the vulnerability of areas to lava flows, pyroclastic flows, and ash fall, which would look something like the picture provided. On top of that, there is a lot of community outreach and crowd sourcing to notify those in danger.  Also, eruption scenarios are held for risk assessment and preparedness. 

Sources: 

https://www.gns.cri.nz/Home/Our-Science/Natural-Hazards/Volcanoes

http://volcano.si.edu/database/search_volcano_results.cfm

New Zealand's Seismology

      New Zealand is on the intersection where the subduction between the Indo-Australian plate and Pacific plate occur which makes for frequent seismic activity. Just the other day there was an earthquake 96 km off the coast recorded at a 5.0 magnitude. A single earthquake does not accurately represent the seismic activity common in the region. Since the early 1900’s, there have been 15 other M7.5+ earthquakes, making the Indo-Australian plate one of the most seismically active in the world. When scaling back and looking at the total amount of earthquakes it becomes clear the majority have a relatively small magnitude; with more shallow seismic activity occurring compared to deeper activity. The following maps show the past ten years of shallow and deep earthquakes.

              

       However, this is not to say that New Zealand is less susceptible to large-scale events. On November 14, 2016, a recorded 7.8 was felt throughout the entire country and is described as one of the largest, most complex earthquakes ever recorded with modern technology. What made it complicated and unusual was the fact it traveled through 12 major crustal faults. It was the most powerful seismic event occurring in New Zealand in over 150 years which “resulted in surface slip of more than 10 m along multiple faults, several of which were previously unmapped or considered inactive, despite New Zealand having one of the most accurate and comprehensive maps of active faulting worldwide” (Hamling et al. 1). Because earthquakes are a frequent part of life for any of those living in the country, New Zealand has taken many proactive measures to ensure preparedness. The below map shows the location of seismographs the country has for early detection and prediction. The country has also passed legislation requiring buildings to be up to code a structurally sound to survive frequent seismic activity as well as offering numerous websites that inform and prepare the population for earthquakes, eruptions, and tsunamis.

Works Cited 

“Building (Specified Systems, Change the Use, and Earthquake-prone Buildings) Regulations 2005.” Parliamentary counsel office, http://www.legislation.govt.nz/regulation/public/2005/0032/latest/DLM313976.html?search=ts_regulation_building_resel&p=1. Accessed 6 September 2018.

Hamling, Ian J, et al. "Complex Multifault Rupture during the 2016 Mw 7.8 Kaikōura Earthquake, New Zealand." Science (New York, N.Y.), vol. 356, no. 6334, 14 Apr. 2017. EBSCOhost, doi:10.1126/science.aam7194. 

“Seismicity in New Zealand.” Branz, http://www.seismicresilience.org.nz/topics/seismic-science-and-site-influences/seismicity-in-new-zealand/. Accessed 6 September 2018.

Seismological Society of America. "Seismologists offer detailed look at New Zealand's Kaikoura earthquake." ScienceDaily. ScienceDaily, 12 April 2017. <www.sciencedaily.com/releases/2017/04/170412111125.htm>. Accessed 6 September 2018.