Fifty Years of Turmoil in One Minute – The Recent Living Respiring Dynamic Earth

A screenshot of the Global Volcanism Program's Map of Eruptions, Earthquakes and Emissions $ ($E3$ )$ from The Smithsonian National Museum of Natural History, taken at time t = August 2010, showing details of the Icelandic volcano eruption of Eyjafjallajokull on 14th April 2010.Visualizing Dynamic Earth

We live on the ever-changing planetary surface of Earth.  Now, the Smithsonian National Museum of Natural History’s “Eruptions, Earthquakes, & Emissions” (“E3”) web application reveals a time-lapse animation of the data held on volcanic eruptions and quakes on Earth since 1960.  The dynamic Earth at one glance!

The interactive map of Earth reveals the data held on the volcanic eruptions of the last decades.  It shows volcanic gas emissions (sulphur dioxide, SO2) since 1978 – the first year that satellites were available to provide global monitoring of SO2.

 

A screenshot of the Global Eruptions Earthquakes and Emissions web-based application of the Smithsonian Natural History Museum.
Click on the picture to reveal the Global Volcanism Program (GVP) animated web-based application.

The Global Volcanism Program

The volcanic eruption and gas emission data are drawn from the Volcanoes of the World database maintained by the Smithsonian’s Global Volcanism Program (GVP).  The eruption and volcano data can currently be downloaded through options under the Database tab.

The earthquake data are pulled from the United States Geological Survey (USGS) Earthquake Catalog.

As well as monitoring active volcanoes, the global collaboration of researchers is gathering evidence of ancient eruptions in the geological record.

A 1910 black and white photographic portrait of Alfred Wegener.
Alfred Wegener (1880-1930)

We live at the surface of a very dynamic Earth indeed.  A planet that respires right under our very eyes.

When dinosaurs roamed the Earth, the continents were all gathered together into ONE land mass called Pangaea.  Over the 250 million years that followed, this single land mass broke apart, and the pieces began to travel to their current positions.

Note the speed India travels toward Asia about 60 million years ago.  The resulting collision, which continues to this day, built the Himalayas.

In 1912, German scientist Alfred Wegener made some observations that would turn both the worlds of Geology and Oceanography on their heads!!

A diagrammatic map designed and re-designed by Snider, Pellegrini and Wegener of the similar fossil patterns that can be found across several (nowadays distant) continents.
Map of Fossil Patterns across the Continents Source: Wikipedia

Wegener noticed that:

  • similar plant and animal fossils were found both in Africa and South America, as well as on other remote continents separated by oceans
  • similar rock formations were also found on distant continents
  • if joined together, the coastlines of Western Europe and Africa appear to fit like jigsaw pieces with those of North and South Americas.

 

Continental Drift

Wegener concluded that these formations used to be part of a single landmass, then later divided.  In other words, the continents of Earth were once connected into one super continent – the “Pangaea of the Carboniferous”, but had since then increasingly separated and drifted apart.

In 1915, Alfred Wegener formulates his “Continental Drift” theory – the central concept is that:

  • The continents float atop the mantle (a heavier, denser layer of rock deep within the Earth)
  • The heat rising within the hot mantle created currents of partially melted rocks that move the continents around the earth’s surface.

Wegener’s idea was initially rejected by his peers, until the Theory of Plate Tectonics came along to explain how the continents move.

 

A gif animation illustrating continental drift over the millenia.
An Animation of Continental Drift: Over the past 250 million years, the single land mass of Pangea broke apart, and the resulting pieces began to travel to their current positions at a rate of 2.5 cm/year.

The Continents Are Moving!

The continents are moving, along with the sea floor, at a rate of about 2.5 centimetre per year (2 inches/year).  So, they may not travel very far over a human life span, but the distance does add up over millions of years.

About 500 million years (Ma) ago, southern Britain was part of a small continent situated about 60° S of the Equator.  Northern Britain was part of a larger continent about 15° S.

The two blocks were initially separated by the Iapetus Ocean, which was at its widest in the early Ordovician.

A diagram showing a subduction zone at the surface of the Earth. It shows how the lithosphere, located underneath the oceanic crust, can actually be pushed inside the astenosphere, at its junction with the continental crust. Source: USGS
The Process of Subduction of the Earth’s crust – a geological process that takes place at the convergent boundaries of tectonic plates where one plate moves under another and is forced down into the mantle.  Source: USGS.gov

The closure of the Iapetus Ocean by a process of subduction around its edges, consumed the oceanic crust, causing much igneous activity, especially andesitic volcanism.  When the continents collided, the Caledonites mountain belt was thrown up, and granites intruded its deformed crust.

About 400 Ma ago, the main pieces of continental crust making the British Isles today eventually gathered up.

About 30 Ma ago, the distant collision of Africa with Europe produced the Alps, and its impact on Britain are still seen in the vertically tilted Jurassic and Cretaceous sediments along the Dorset coast and on the Isle of Wight.

 

A screenshot of the Smithsonian GVP's E3 application providing data on the Eyjafjallajokull volcano.
The Smithsonian’s web-based interactive application provides a wealth of information on volcanoes, such as the Icelandic stratovolcano Eyjafjallajokull. Source: volcano.si.edu

Predicting Dynamic Earth

The Smithsonian’s GVP has been running since 1968.  The global network of scientist has been building a database of all known and confirmed eruptions for the last 10,000 years.  Its mission is to “document, understand and disseminate information about global volcanic activity”.

Some eruptions have remained as signals of ancient ash or lava left in rocks.  But the program also looks at the scientific literature, eyewitness accounts and even old ship’s logs – some of which contain detailed accounts of volcanic eruptions.

 

The last 5 decades are a crucial period, because the scientists say they are confident that they have a complete record of every eruption and earthquake over that time.

 

A photograph showing Eyjafjallajokull's lava curtain on 21st March 2010.
Eyjafjallajokull volcano’s ‘Curtain of Fire’ during the 2010 eruption…

Forecasting Volcanic Eruptions

Making it available to download and in an app makes it valuable to worldwide scientists who are looking for patterns that help to improve our understanding of volcanic eruptions, and ultimately provide potentially life-saving earthquake forecasts.

Although individual volcanic eruptions on a human timescale can seem rare, volcanic arcs – chains of volcanoes along the same plate boundary – have a sort of “pulse”.

Scientists and the general public will now be able to look for global patterns in the timing and geography of events.

They can look at a recurrence interval on the geological timescale.

What is really the most critical about this volcanic eruptions data-gathering effort exceeds what you can see in the animated application.  It is about seeing the numbers of fatalities and the characteristics of each of these eruptions.

The study allows the program to forecast not only when an eruption might be expected, but what a particular volcano will produce when it erupts.

And there are eruptions happening literally all the time!!