Causes and Measures of Earthquakes in New Zealand

New Zealand is a stunning pacific island country, but there are tens of thousands of earthquakes of varying magnitudes every year. Small earthquakes can make light bulbs swing and even feel unnoticed. The worst earthquakes crack the ground and damage buildings, bridges and other infrastructure. Therefore, it is necessary for New Zealanders to understand the occurrence mechanism of earthquake disaster and learn how to take emergency measures.

Earthquakes are powerful natural forces deep inside the earth, and the causes of earthquakes are closely related to plate tectonics. Plate tectonics is the most important concept in modern geography, which describe the movements of a large number of plates. One of the biggest factors that affect the frequency of large earthquakes is the rate of movement between the plates. Academic circles generally believe that there are seven plates which cover nearly 95% of the world’s surface namely Pacific plate, North American plate, Eurasian plate, African plate, Antarctic plate, Indo-Australian plate and South American plate. The Earth’s seas and land sit on top of these plates. Drifting plates may slowly scrape each other, separate or bump together. Consequently, this can make mountains rise, earthquakes occur and volcanoes erupt.

The main reason for the earthquakes in New Zealand is that it is located at the boundary of both the Australian and Pacific plate tectonic (Tectonic setting of New Zealand, n.d.). These locations are called subduction Zones, where one plate tectonic subducts under another. Subduction Zones are the most common type of fault due to the subduction of the Pacific plate under the Australian plate in New Zealand. In addition, not only do subduction Zones produce large earthquakes, but also such catastrophic earthquakes are responsible for most of the ocean-wide tsunamis, such as the most serious tsunami in Japan in 2011.

The Hikurangi subduction zone is an important factor in the occurrence of major earthquakes in New Zealand. Although the Hikurangi subduction zone is one of the major subduction systems in the world, little is known about the frequency and intensity of the Hikurangi subduction earthquakes. Because New Zealand’s seismic record is only 170 years old, no subduction earthquake greater than magnitude 7.2 has been recorded. The Kaikoura earthquake in November 2016 had a magnitude of 7.82, which was felt in many parts of New Zealand and was one of the most complex earthquakes ever recorded in the world.

Historic records dating from the 1840s show that, on average, New Zealand has several magnitude-6 earthquakes every year, and one magnitude 7 every 10 years, and a magnitude 8 every century (Earthquake, n.d.). New Zealand is high risk for earthquakes, especially in Wellington-Hutt valley segment of the Wellington Fault. A GNS science study estimate the probability that more people could be killed by the resulting tsunami than the earthquake itself and many houses could be at risk from landslides in the hills (Joanna wane, 2019).

Earthquakes sometimes lead to collapse of houses, the destruction of bridges and roads, resulting in a large number of casualties. In order to reduce the potential damage caused by earthquakes, the government must formulate corresponding policies and earthquake emergency plans, and individuals must master the necessary measures to avoid risks.

The government needs to pay attention to the following aspects:

Establish a proper and formal building standard. The standards divide New Zealand into three different sectors as A, B and C, which reflect the degree to be prone to quake. The A zone is the highest risk implement base isolation. The approach involves a lead-rubber bearing system designed by Dr Bill Robinson in the 1970s,which was one of the most innovative developments and unique in the world at that time.(Matthew Wright,2014)The technology, applied to the parliament building of New Zealand and Te Papa museum, is designed to withstand earthquakes of up to magnitude 8.4.The technology has also been used in other countries such as Japan and China, where it is widely used in modern buildings to protect against the dangers of strong earthquakes.

Draw tsunami evacuation maps and publish it on city council as well as Civil Defence website for the convenience of citizens. It is important that publics should be familiar with the escape route. For instance, in Japan,3000 school students in one coastal city survived the disastrous 2011 tsunami because they followed a well- practiced emergency evacuation procedure.

Improve the natural disaster insurance system. In order to reduce the loss of property caused by the earthquake disaster, it is necessary for the public to buy natural disaster insurance including houses, furniture and other property.

Individuals need to make adequate emergency preparations before, during and after an earthquake:

Before an earthquake:

• Develop a household emergency plan.
• Prepare an emergency kit, including food, water and medication.
• Practice drop, cover and hold.
• Make your home safer and secure heavy items of furniture to the floor or wall.

During an earthquake:

• If you are indoors, move no more than a few steps and drop, cover, hold until the shaking stops.
• If you are in an elevator, drop, cover and hold. When the shaking stops, get out at the nearest floor.
• If you are outdoors, move away from buildings, trees and power lines, then drop cover and hold.
• If you are at the beach, move to higher ground immediately in case of a tsunami.
• If you are driving, stop and stay in the car with seatbelt fastened until the shaking stops, then proceed with caution.
• If you are in a mountainous area, be care for falling debris or landslides.

After an earthquake:

• Be careful of aftershocks.
• Listen to local radio and get official rescue information.
• Turn off the power and gas to make sure there is no fire.
• Leave the dangerous building without using the elevator.
• Check yourself for injuries and help others if you can.

Due to the unique geographical location of New Zealand, earthquakes have become a part of people’s lives and are inevitable. Therefore, everyone needs to understand its scientific mechanism and know the earthquake risk. When the earthquake suddenly comes, we cannot calmly deal with unless we have made full emergency preparedness for the tremor.

References

• GNS SCIENCE. (n.d.). Plate Tectonics. Retrieved from https://www.gns.cri.nz
• Joanna Wane. (2019). The worst natural disaster risks facing New Zealand. Retrieved from https://www.noted.co.NZ
• Matthew Wright. (2014). Living on shaky ground. Auckland, New Zealand: Random House New Zealand.
• GET READY GET THRU.(n.d.).Earthquake. Retrieved from https://www.getthru.govt.nz
• Sally Blundell.(2018).Where New Zealand’s next big earthquake is going to strike. Retrieved from https://www.noted.co.NZ