How They Are Made

Volcanoes are caused by magma rising to the surface of the earth (the crust) and eventually erupting due to an increase in pressure. The magma can make its way through the crust in 2 distinct ways: along convergent plate boundaries and at volcanic hot spots. The creation and movement of these plate boundaries over time is a result of mantle convection. Mantle convection is the process of warm, less dense, underground magma flow up towards the surface of the earth (crust), before cooling, becoming denser and flowing back towards the core of the earth. This process results in parts of the crest being either pulled apart or together depending on the direction of the flow of magma on either side of a point. Magma makes its way through the crust most commonly at subducting convergent boundaries (one plate butting under another as the result of them colliding) and divergent plate boundaries because that is where cracks in crust are. As you can see in the map to the left, global volcanoes form a linear pattern along plate boundaries, affirming the interrelationship between cracks in the earth and magma rising through it to form volcanoes. Volcanic hotspots are located at areas under large plates where large amounts of suppressed magma can break through thin parts of the crust to form volcanoes. On the right is a visual highlighting how a hot spot can form volcanoes as magma breaks its way through the crust. The multiple islands in a row are the result of the movement of plates over time, creating new islands and volcanoes above the hot spot. Volcanoes erupt when the buildup of pressure over time becomes too great and magma has to escape. The greater the pressure, the larger and more violent the eruption.

Timeline of Events

1. Mantle convection forms and causes the movement of plate boundaries
2. Magma makes its way through the cracks in the crust along these plate boundaries
3. Buildup of underground pressure causes a volcanic eruption

Global Systems

Both of my hazards are caused by plate tectonics and the movement of these plates over time. Above I mentioned the process of mantle convection and how it causes the movement of crustal plates. The visual to the right shows how the movement of magma (the red arrows) can pull and push the tectonic plates, causing them to move: breaking apart and colliding. This movement is related to volcanoes because without cracks in the earth's crust, this underground magma would never be able to be released into the surface in the form of an eruption. The movement also causes earthquakes when 2 plates get stuck on each other and build up pressure before having to suddenly release: causing the ground to shake. (more on earthquakes later)

How We Detect Them

GPS Movement Detection

As magma underneath a volcano begins to gain pressure and move around it can cause the ground above it on the surface to deform and inflate. When and how volcanoes move and deform can help scientists predict the time of eruption as well as how it may erupt. Using modern GPS technology they can both detect and measure movements and changes in the shape of volcanoes in advance. This is done by recording and measuring the difference between separate passes of the GPS satellite (see photo to the right). The picture to the left shows a model containing data obtained using GPS showing how magma and volcanoes expand with arrows corresponding to horizontal motion and different colours visualising vertical motion.

Depending on collected data geophysicists can determine:

• If magma is collecting underneath a vent
• A lot of lava is flowing
• If magma is leaving the main vent and perhaps moving to escape somewhere else

These findings can allow us to prepare in advance in order to save people’s lives and homes.

Spectrometer

Volcano scientists used to make measurements in unsafe environments, or fly helicopters over volcanoes in order to analyze the gas being emitted from a volcano. New technology provides spectrometers to measure the amount of sulfur dioxide being released from the volcano. This is done because sulfur dioxide content is an indicator of the amount of magma beneath the volcano and can allow scientists to make educated predictions about the behaviour of volcanoes. By determining ratios of the sulfur dioxide to other gases they can also figure out the depth of the magma, and how the gas is reaching the surface or which paths the magma may be coming through. The way the spectrometer measures the amount of gas from a volcano's plume is by comparing the amount of light shining through the plume to identify the gas. Then knowing how far away the plume is, and how fast the wind is blowing, they can identify the amount of gas. In the split diagram to the right the measuring of gas is shown, with an older vehicle method on the left side and the more modern remote spectrometer to the right.

How They Happen

Earthquakes are also caused by the movement of plate boundaries and occur along plate boundaries and smaller cracks in the crust known as fault lines. Earthquakes by definition are the “sudden shaking of the earth’s crust caused by the movement of heat within the earth”. This movement of heat is mantle convection and the shaking of the crust is movement along plate boundaries or fault lines. Earthquakes occur when two separate pieces of the earth's crust rub up against each other and get stuck, slowly building up more and more pressure before a sudden release and movement that is an earthquake. As you can see in the diagram below, the two plates are pushing into each other, forcing themselves to build up pressure before releasing, and shooting in a certain direction. In this case the yellow arrows show the movement of the plates as a result of releasing pressure, this would be the movement of the ground that we recognize as an earthquake. The wonderful 3d model to the right illustrates the inner workings of a huge, 7.4 magnitude earthquake that took place on April 3, 2024 just off the coast of Taiwan killing 18 people. The curved 'slide' in the model is a subduction zone at the Eurasion plate, meaning two plates are colliding and one slides underneath the other. In this case this resulted in what's called a reverse or thrust fault, when the one plate suddenly moves above the one below it.

Timeline of Events

1. Tectonic plates move against each other
2. They get 'stuck', and slowly build up pressure because they are still trying to move
3. The pressure is finally released in a sudden, ground shaking movement

How We Detect Them

GNSS Receiver System

A new way of detecting earthquakes faster than ever has been only recently developed, using portable receiver stations (see image to the right) sending signals to satellites orbiting the earth. These satellites are a part of the Global Navigation Satellite system or GNSS. The way the system detects seismic activity is by constantly sending the receiver's exact location in order to detect any sudden movements or deformations of the earth's crust. Despite being significantly less accurate compared to other seismic monitoring devices, this system allows for the current data being transmitted from the receiver to be sent to any internet connected device within seconds. The speed of transmission allows the characterization and analysis including the magnitude of an earthquake to be determined within seconds, before it has even ended.

Seismogram

The last method directly measured large (centimetre) movements, whereas seismographs or seismometers detect seismic waves that get sent out from an earthquake's origin as it begins, recording the ground movements as a seismogram. Most seismometers work because of the law of inertia: a suspended mass will stay still while the ground is moving. Attaching a pen to that mass will allow you to graph a model of the ground's movements (see visual to right). Modern seismometers however don't draw anything, instead they convert these vibrations into electronic signals that can be graphed on a computer. Using the data collected scientists can locate the origin of earthquakes by finding the difference between the arrival of 2 different kinds of seismic waves that occur, the P- and S-waves. (see visual to left)

Humans

There are many reasons why people still live in Iceland, however the most contributory include:

• Safety
• Cleanliness
• Affordability
• Environment

Iceland is well known as one of the world's safest countries with very low crime rates. So safe to the point that police do not carry guns, and families commonly leave their babies in strollers outside of houses and restaurants! Iceland is also very clean with 100% green energy powered by a combination of hydroelectric and geothermal plants, and a lack of polluting industries. Because of the sustainable and clean nature of their energy system, they provide some of the cleanest water on earth, along with air that contributes to an average life expectancy of 83 years (see the historical graph showing the increase of life expectancy over time in Iceland to the left). Similarly to Canada, Iceland boasts a very affordable Icelandic Health Insurance System which caps the amount of money that will be spent on hospital expenses per month (not including child births and pregnancy check ups which are free). After living there for around a year the amount is capped at about $40 Canadian. Last, but certainly not least, is the picturesque environment that drives a healthy tourism economy which is estimated to be responsible for over 10% of Iceland’s GDP. Only 20 minutes away from the capital Reykjavik you can be hiking a mountain, riding Icelandic horses or walking along a beach. Not to mention the front row seat views of the northern lights (see the stunning picture to the right).

Climate

Iceland has the Koppen climate classification symbol of both Cfc in the south and west, and ET in the rest and most of Iceland. Cfc describes a temperate, rainy climate with cool and short summers. Whereas ET is a drier, colder tundra climate. The average temperature in the winter is 0 °C in the south, and -10 °C in the north with lows of around 25 - 30 °C. They experience strong winds and frequent storms in the winter.

Flora and Fauna

Iceland is within both a taiga (or boreal forest) biome as well as a tundra biome. In the northern tundra biome, vegetation mostly consists of mosses and lichen, most commonly: Iceland moss or Cetraria islandica (see picture on the left). Iceland moss can be found in large amounts on mountain and lava slopes displaying its pale chestmark colour. In the small remaining area with suitable conditions, short trees survive with tree species such as the sitka spruce (Icelandic name: Sitkagreni), black cottonwood and lodgepole pine along with a variety of berry species. The running joke I discovered in my research was:

‘What’s your best move if you get lost in an Icelandic forest?’

‘Just stand up!’.
Although this is usually the case now, Iceland used to have a much bigger, in both quantity and height, population of trees. This changed after settlers began to arrive from around 870 AD and chop down trees at an unsustainable rate. They needed the wood because it was Iceland's main source of energy until being replaced around the mid 20th century. Livestock also had its role by devouring the local vegetation. As for animals, Iceland has only one native animal remaining: the arctic fox (image with a summer coat to the right). Common animals include Atlantic salmon, brown trout, Arctic char and European eels in the rivers and lakes, merlins, snowy owls, white tailed eagles, ducks, geese and skua in the skies, and minks, reindeer and mice, to name a few.

Natural Disasters

Iceland has a very unique and possibly dangerous location. This is because not only is it right on top of a plate boundary between the North American and Eurasian plates (spanning a solid 40,000 km along the ocean floor), but it is also a volcanic hotspot (see plate boundary visual to the right and hot spot visual to the left). Knowing how volcanoes and earthquakes are caused, it is clear that Iceland is vulnerable to both. Iceland is located above this hot spot because of how it was formed. When magma from the hot spot burst through the ice of a glacier, opening holes to push out sand, glass and water: it formed the beginnings of the island known as Iceland.

Earthquakes

Earthquakes in Iceland are very frequent. Within only the last 48 hours (of time of writing) numerous earthquakes took place in Iceland, with the locations of each being shown to the right. The movement of the tectonic plates that are causing these earthquakes, as well as the seismic zones of Iceland are shown in the bottom diagram to the left. As you can see the plate boundary it sits on (often called the Mid Atlantic Ridge) is moving westwards, as a result of the hot spot pushing upwards and outwards. From the 11th century to 2000, 33 ‘damaging’ earthquakes took place, with the worst killing around 1000 people near the town of Selfoss in 1706. The majority of these earthquakes occurred in the southern region of Iceland (Suðurland in Icelandic) highlighted in red in the other map to the left. If you compare this southern region to the recent data from the last 48 hours and the map of seismic activity, you can see that this is a common pattern of seismic activity persisting throughout thousands of years due to the movement of the Mid Atlantic Ridge.

Volcanoes

Since the last ice age 10,000 years ago, a third of all lava that has reached the Earth's surface from volcanoes has erupted in Iceland. The established spreading of the Mid Atlantic Ridge, combined with the hot spot below, fills the gaps between the crust with magma: resulting in frequent volcanic activity. Currently there are over 30 active volcanoes in Iceland, historically one of these volcanoes would erupt every 5 years. However, since 2021 eruptions have been more frequent, occurring more like once a year. The most (in)famous modern eruption in Iceland took place between March and June 2010 at Eyjafjallajökull, a stratovolcano standing over 5,400 ft in the air with a crater 3-4 km in diameter, covered by an ice cap. The sheer volume of volcanic ash (see the top global view to the right) emitted in the eruption resulted in millions of tourists being stranded as over 100,000 flights were cancelled across 20 Western European countries.

See some more cool pictures below:

North view of (from left to right) Mýrdalsjökull, Fimmvörðuháls and Eyjafjallajökull on 4 April 2010, taken from an altitude of 10,000 metres (32,800 ft)

By Max Haase - Transferred from en.wikipedia to Commons., CC BY-SA 3.0, Link

Overlooking the Eyjafjallajökull glacier and the ongoing volcano eruption from Hvolsvöllur on April 17th, 2010.

By Boaworm - Own work, CC BY 3.0, Link

Second fissure, viewed from the north, on 2 April 2010

By Boaworm - Own work, CC BY 3.0, Link