Why Earthquake often happens in NEW ZEALAND ?

New Zealand is located in a region that is highly prone to seismic activities. The country is situated at the boundary of the Pacific and Australian tectonic plates, which makes it highly susceptible to earthquakes. New Zealand has experienced several major earthquakes in the past, which have caused significant damage and loss of life. In this article, we will explore why earthquakes often happen in New Zealand.

Geological makeup:

To understand why earthquakes often happen in New Zealand, it’s important to understand the country’s geological makeup. New Zealand is situated on the Ring of Fire, which is a region that is highly prone to seismic activities. The country is located at the boundary of the Pacific and Australian tectonic plates, which are constantly moving and grinding against each other. This movement causes a lot of pressure and tension to build up, which can lead to earthquakes.

In addition to being situated on the Ring of Fire, New Zealand also has several active faults that run through the country. These faults are cracks in the Earth’s crust where the two tectonic plates meet, and they can cause earthquakes when they move. Some of the most active faults in New Zealand include the Alpine Fault, the Hikurangi subduction zone, and the Wellington Fault.

Frequency and Magnitude of Earthquakes:

New Zealand experiences a large number of earthquakes each year due to its position on the Ring of Fire and the presence of active faults. According to the Geonet website, New Zealand experiences over 20,000 earthquakes each year, with around 200 of them being strong enough to be felt by people. While most of these earthquakes are small and mild, the country has had its fair share of major and deadly earthquakes.

One of the most significant earthquakes in New Zealand’s recent history was the Christchurch earthquake of 2011. This earthquake had a magnitude of 6.3 and caused the deaths of 185 people. It also caused significant damage to infrastructure and buildings in the city. Another significant earthquake in New Zealand’s history was the Napier earthquake of 1931, which had a magnitude of 7.8 and caused the deaths of 256 people.

Risk Mitigation:

Given the high frequency and magnitude of earthquakes in New Zealand, it’s crucial for the country to have robust risk mitigation strategies in place. The New Zealand government has several initiatives in place to help mitigate the impact of earthquakes, such as building codes that ensure new buildings are earthquake-resistant.

The government also has a nationwide earthquake early warning system in place, which gives people and businesses vital seconds to prepare for an earthquake. In addition, the country has a strong emergency management system that is activated in the event of an earthquake.

Earthquakes often happen in New Zealand due to its position on the Ring of Fire and the            presence of active faults. While the country experiences a large number of earthquakes each year, the government has several risk mitigation strategies in place to reduce the impact of earthquakes. While it’s impossible to predict when the next major earthquake will occur in New Zealand, it’s   important that the country remains vigilant and prepared to deal with the aftermath of any earthquake that does occur.

The Alpine Fault: The Alpine Fault is one of the most significant faults in New Zealand. This fault runs for over 600 km through the South Island and moves at a rate of around 30 mm per year. The last major earthquake on this fault occurred in 1717, and it’s estimated that the fault ruptures approximately once every 300 years. Scientists predict that the next massive earthquake on the Alpine Fault could have a magnitude of around 8.0.

Subduction zone: The Hikurangi subduction zone is another significant geological feature that contributes to the frequency of earthquakes in New Zealand. This subduction zone is where the Pacific Plate is forced beneath the Australian Plate, and it runs along the east coast of New Zealand’s North Island. The Hikurangi subduction zone has the potential to produce large-scale earthquakes and tsunamis, as seen in the Kaikoura earthquake of 2016.

Human activity: While natural geological factors are the primary cause of earthquakes in New Zealand, human activity can also contribute to seismic activity. For example, the construction of large dams and reservoirs can cause earthquakes due to the weight of the water, and oil and gas drilling can trigger earthquakes by altering the pressure within the Earth’s crust.

Tsunamis: Earthquakes in the ocean can trigger tsunamis, which are waves that can cause significant destruction when they reach the coast. New Zealand is situated in an area that is prone to tsunamis, and the country has experienced several devastating tsunamis in the past, including the 2004 Indian Ocean tsunami and the 1960 Chilean tsunami.

Plate Tectonics: Earthquakes are principally caused by the movement of Earth’s tectonic plates, and New Zealand is situated at the boundary of the Pacific and Australian plates. The boundary where these two plates meet is known as a subduction zone, which is a region where the denser and heavier oceanic plate is forced beneath the lighter continental plate. This process is known as subduction and creates enormous amounts of pressure between the two plates, which builds up over time. When that pressure is released suddenly, it is in the form of an earthquake.

Volcanoes: New Zealand is home to several active volcanoes, which are another cause of seismic activity. When a volcano erupts, it can cause earthquakes due to the release of pressure and the movement of magma beneath the Earth’s surface. The Taupo Volcanic Zone in the central North Island is one of the most active volcanic regions in New Zealand and has been responsible for some of the largest volcanic eruptions in the world.

Earthquake Swarms: Earthquake swarms are a series of small earthquakes that occur within a relatively short timeframe. New Zealand experiences earthquake swarms regularly, and scientists believe that they may be a sign that a larger earthquake is about to occur. Earthquake swarms can be caused by several factors, including changes in tectonic plate movements or the sudden release of pressure in an area’s fault system.

Liquefaction: liquefaction is a geological process that occurs during an earthquake. It happens when water-saturated soil is shaken by an earthquake, causing it to behave like a liquid. This can lead to the collapse of building foundations and significant damage to infrastructure. New Zealand has experienced several instances of liquefaction during earthquakes, including in the 2011 Christchurch earthquake.

Indigenous Māori legends: Māori people, who are the indigenous people of New Zealand, have legends that explain the occurrence of earthquakes. According to Māori legend, earthquakes are caused by the struggles of two siblings, Matau and Wakarusa, who are both children of the Earth Mother, Papatūānuku. These siblings are said to be struggling in the realm known as “Te Ao Marama”, which translates to the world of light. The idea behind this legend is that the natural world is made up of interconnected systems, and the human world is a place of harmony with the environment.

While New Zealand is known for being prone to earthquakes due to its geological location, there are still many unknowns and mysteries surrounding these seismic events. 

Slow Slip Events: Scientists have identified a phenomenon known as slow slip events in New Zealand. These events involve the gradual movement of tectonic plates over several weeks or months, rather than the sudden movement that occurs during an earthquake. Slow slip events can cause small earthquakes in the region and may indicate a higher risk of a larger earthquake occurring in the future. However, researchers are still unsure why these slow slip events occur.

Seismic Gaps: Seismic gaps are areas of a fault line that have not experienced significant seismic activity in a long time. These gaps have the potential to generate a large earthquake when they rupture. New Zealand has several areas with seismic gaps, including the Alpine Fault and the southern Hikurangi subduction zone. While scientists can identify these areas, predicting when a large earthquake will occur in these gaps remains a mystery.

Earthquake Lights: Earthquake lights are a rare phenomenon that occurs during some earthquakes. These lights appear in the sky as flickering flames, flashes of light or glowing orbs. No one knows for certain what causes earthquake lights, but there are several theories. Some scientists speculate that the lights are caused when rocks are under intense stress and release electrical charges, while others believe that they are related to the release of gases during an earthquake.

Seismic Holes: Scientists have discovered strange holes in the ground that appear after an earthquake. These holes can be several meters deep and are usually found near the epicenter of an earthquake. The cause of these holes is still unknown, but researchers speculate that they may be related to the release of gas or water during seismic activity.

Long-Range Seismic Signals: Long-range seismic signals are low-frequency vibrations that can be detected thousands of kilometers away from an earthquake. These signals can last for days and may be caused by the Earth’s crust and mantle vibrating in response to the earthquake. While long-range seismic signals can be detected, it remains a mystery why they occur.

While New Zealand is no stranger to earthquakes, there are many mysteries and unknowns surrounding these seismic events. The slow slip events, seismic gaps, earthquake lights, seismic holes, and long-range seismic signals are just some of the mysteries that scientists are still trying to understand. As technology improves, researchers hope to unlock the secrets of earthquakes and find ways to predict and mitigate the damage they can cause. Until then, New Zealanders will continue to live with the ever-present risk of seismic events and hope for the best while being prepared for the worst.

New Zealand is situated in an area prone to earthquakes, which can be attributed to its location at the boundary of the Pacific and Australian tectonic plates. The country’s geology is complex, with active faults, subduction zones, and volcanoes all contributing to its seismic activity. While earthquakes can cause significant damage and loss of life, the New Zealand government has implemented robust risk mitigation strategies to minimize the impact of potential disasters. This includes early warning systems, earthquake-resistant building codes, and emergency management systems. Despite the presence of risks posed by earthquakes, the people of New Zealand remain resilient and prepared to deal with the aftermath of any seismic activity.

Overall, New Zealand’s geology and location make it highly prone to seismic activity, and earthquakes are a frequent occurrence in the country. However, the government’s robust risk mitigation strategies and emergency management system mean that the impact of earthquakes can be reduced, and its citizens can remain as safe as possible.

By . NTEZIYAREMYE RONALD