Iceland geology · Volcano and earthquake activity in Iceland
Iceland is a tiny Nordic country located in the North Atlantic. The country is spread over an area of 103,000 sq.km. Iceland’s capital is Reykjavik.
The history of settlement in Iceland dates back to 874 AD. The first person to settle in the country was a Norwegian chieftain, Ingólfr Arnarson.
In the following centuries, many Norwegians and some Scandinavians settled in the country. These settlers brought with them slaves of Gaelic origin. Iceland is the birthplace of one of the world’s oldest functioning legislative assemblies, the Althing.
The Althing governed the country until the 13th century when Iceland acceded to Norwegian rule. In 1523, Iceland came under Danish rule. The country got its independence in 1918. Though the Althing was suspended from 1799-1845, it is still the oldest running parliament in the world.
Until the 20th century, Iceland’s economy was heavily dependent on fishing and agriculture. The industrialization of fishing proved vastly beneficial for the economy, and Iceland became one of the richest and the most developed economies in the world.
In 1994, Iceland became a part of the European Union Area. The move helped diversify the economy into different sectors, such as manufacturing, finance, and biotechnology. Today, Iceland is one of the most peaceful and developed nations in the world.
Iceland is known for its breathtaking natural beauty. The tiny Nordic country is blessed with scenic landscapes. Iceland is nicknamed the land of fire and ice. It is one of the few countries in the world where you can find both volcanoes and snow-covered landscapes.
Iceland has one of the most geologically active landscapes in the world. Iceland is highly prone to earthquakes. It is estimated that the country’s national monitoring seismic network, on an average, detects around 500 earthquakes every week, which means that there were almost 70 earthquakes in Iceland today.
Thankfully, most earthquakes that hit the country are small tremors.
Most earthquakes in the country occur along the South Icelandic Seismic Zone and active volcano zones. Earthquakes in the country can be broadly classified into two categories- earthquakes caused due to volcanic eruptions and quakes caused due to the tension released by the movement of tectonic plates.
Earthquake monitoring mechanism in the country
Over the years, Iceland has invested heavily in building a sophisticated earthquake monitoring system. The country has developed capabilities to use data to monitor earthquakes and volcanoes.
Live earthquake monitor
Many government bodies and private players have developed live earthquake monitors. These monitors are designed to provide warnings related to seismic activities so that appropriate steps can be taken to mitigate losses. These systems provide and collect data related to live earthquakes.
The Icelandic Meteorological Office manages a sophisticated network of seismographs that cover the active zones in the country. Portable seismographs are used to record important information related to crustal processes.
The moment an earthquake hits a region, the system pinpoints the region on the Iceland earthquake map.
Icelandic Strong-motion Array or ICCERAY includes 14 strong-motion stations scattered throughout South Iceland Seismic Zone. Each strong-motion station utilizes a seismograph. Most units are located in basements of residential buildings in the town center of Hveragerdi.
Thanks to these systems, the country’s capability to track and monitor Iceland earthquakes and volcanoes has drastically improved. Once the system detects seismic activity in a region, news agencies in the country provide Iceland earthquake latest news.
The Icelandic weather page includes a map that shows earthquakes that have hit the country in the last 48 hours.
Iceland geology – Volcano and earthquake activity in Iceland
It is believed that a series of volcanic eruptions resulted in the formation of Iceland around 24 million years ago.
Many experts believe Iceland to be the volcano & earthquake center of the world, and for good reasons.
Thanks to Iceland’s unique location (the country represents the largest portion of the Mid-Atlantic Ridge and is located above a hotbed), the country has witnessed several volcanic eruptions and earthquakes since its formation.
It is estimated that around 33% of all the magma that has erupted on earth for the last 10,000 years came up in the country. A volcano erupts every four years in the country.
A major volcanic eruption in the history of the country was the 2010 eruptions of Eyjafjallajökull. Though the eruption did not cause any loss to life, it had an adverse impact on the air traffic across western and northern Europe.
Iceland has four major volcanic zones:
- The East Volcanic Zone
- The West Volcanic Zone
- The North Volcanic Zone
- The Reykjanes Zone, which can be subdivided into the Reykjanes Volcanic Belt and the Reykjanes Ridge
The country has around 130 active and inactive volcanoes. Some major volcanoes in the Nordic country include Askja, Hekla, Katla, Helgafell, Eldfell, Grímsvötn, Grimsnes, Bárðarbunga, Grensdalur, Krafla, and Laki.
Hekla, arguably, is the most well-known volcano in the country. It has erupted 20 times since Iceland became a settlement. Hekla, however, isn’t the most active volcano in the country. That title goes to Grímsvötn that last erupted in 2011.
Two major volcanoes in the country, Katla (located under the Mýrdalsjökull glacier) and Bárðarbunga (located beneath the Vatnajökull glacier) has been particularly active in recent years. Katla erupts every 40-60 years. The volcano last erupted in 1918 and is long overdue for an eruption.
The most common type of eruption in the country is fissure eruptions. These eruptions are responsible for the formation of most crater rows that are scattered throughout Iceland. The longest crater row in the country is the Laki crater, which includes 100 craters along a 25 km long fissure.
Iceland sits on a rift zone, which explains why there are so many earthquakes in the country. On a normal week, there are about 150-400 earthquakes in the country. These quakes measure between ML0.0 and ML2.8 on the Richter Scale. A couple of earthquakes may measure up to ML3.0.
On a quiet week, around 50-100 earthquakes hit the country. Most of these earthquakes do not measure more than ML2.5 on the Richter scale. In a week marked by big seismic activities, this number can easily go up to 2000-5000 earthquakes.
Iceland’s latest earthquake (at the time the article was written) hit the country on 22 October 2019. It measured 1.8 on the Richter Scale. The earthquake originated 4.5 km north of Eldey.
To update your knowledge on the latest earthquakes in the country, Google using simple search terms such as earthquakes in Iceland today.
The largest earthquake to hit the country occurred in 1784. It is believed to have measured 7.1 on the Richter Scale. In 1912, the second-largest earthquake measuring 7 on the Richter Scale hit the country.
Why so many earthquakes in Iceland?
A question to ask here is, why does Iceland have so many earthquakes and volcanoes? To find the answer to this question, we need to take a quick look at Iceland’s location.
The Nordic country is situated at a point between the Eurasian and North American tectonic plates. At this point, the two tectonic plates literally pull apart the North Atlantic Ocean.
Is it possible to predict an earthquake?
To date, mankind hasn’t been successful in developing a system that can predict earthquakes. The best scientists can do is use historical data and information related to plates’ motion to forecast an earthquake.
If someone says that they can predict an earthquake, they are either lying or do not know anything about earthquakes.
Predicting an earthquake involves defining three elements:
- The date and time of the earthquake
- The intensity of the quake
- The location of the earthquake
In the past, many people have tried to predict earthquakes. These predictions were rejected due to these reasons:
Most predictions were not found to be based on scientific evidence. There were many cases of people predicting earthquakes on the basis of the movement of clouds or slugs. Many others associated earthquakes with body pains.
Many predictions are generic statements, such as an M4 earthquake will hit a part of the US in the next 30 days.
They failed to define all the three elements required for earthquake prediction.
Many people (non-scientists) claim to predict earthquakes on the basis of certain events, such as unusual animal behavior, a sudden increase in the amount of radon in the local water, and a swarm of low-intensity earthquakes hitting the area.
Predictors consider these events as a precursor to a major earthquake; however, these events are rarely followed by a quake.
A few decades ago, an earthquake prediction was made in China. The basis of the prediction was a swarm of low-intensity earthquakes and inexplicable changes in animal behavior. As a precautionary measure, people continued to sleep out of their homes for days.
The prediction came true when a major earthquake hit the country. This, however, is an isolated case. Earthquake predictions are usually inaccurate.
Why not so huge earthquakes like California or Japan?
Though Iceland is regularly hit by earthquakes, most quakes in the country do not even measure 3.0 on the Richter scale.
Why are earthquakes in Iceland not as intense as in Japan, Chile, or California? To answer this question, we need to delve deep into the geology of the country.
Most earthquakes occur at the boundaries of crustal plates. This is the point where they (plates) rub against each other.
Iceland is situated at the fissure between Eurasian and North American plates. These plates are constantly moving apart. This weakens the intensity of all geological activities that originate under Iceland.
To better understand the underlying cause of low-intensity geological activities in the region, let’s take the example of Chile. Earthquakes in the South American country originate at the point where the Nazca plate is being subducted under the North American plate.
Earthquakes in the country are formed around 100-350 km under the sea level, whereas earthquakes in Iceland start just tens of kilometers under the sea level.
The rule of thumb says that the further underground an earthquake is born, the higher its intensity, which explains why earthquakes in Iceland are milder than Japan or California.
Is an earthquake a sign that a volcano may erupt?
Sometimes in the past, studies have linked earthquakes measuring more than 6 on the Richter Scale to a subsequent eruption at a nearby volcano. That said, research has shown that a volcano can be triggered into eruption by nearby tectonic earthquakes only if they are about to erupt.
This can happen only when the below conditions are met:
- Pressure build-up in the magma storage area
- The volcanic system has a considerable amount of eruptive magma
A study conducted by a team of researchers at the University of California found that earthquakes can trigger volcanic eruptions in the long run.
The team concluded that because earthquakes can have a significant impact on the crustal pathways utilized by magma to move, there is a probability that quakes can result in an eruption.
Earthquake forecast in Iceland
In 2000, a series of earthquakes hit South Iceland. These earthquakes provided a wealth of information related to the earthquake source mechanism, attenuation of seismic waves, and measured peak accelerations. Additionally, the Icelandic Meteorological Office conducts various studies related to past earthquakes.
These studies helped create an accurate earthquake catalog for the country. The Icelandic Meteorological Office uses historical data to forecast earthquakes in the country. The Weather page provides information related to seismic activities.
Over the years, Iceland has participated in prediction research projects with other EU nations. These studies showed that:
Micro-earthquakes in the country provide the most important pre-earthquake information related to the seismogenic zone
Pre-earthquake activity precedes almost every major earthquake in the country
Currently, various studies that focus on creating a model that can predict earthquakes in some way are being conducted in the country.
2008 Iceland earthquake between Selfoss and Hveragerði
In 2008, a doublet earthquake hit the tiny Nordic country. The two main quakes measured 5.9 and 5.8 on the Richter scale. Though there were no human fatalities reported, 30 people sustained injuries. The epicenter of the quake was reported to be between the towns of Selfoss and Hveragerði.