Solving the mysteries of the Earth
It was a couple of earth-science stories that caught my attention this week. After the recent earthquakes that shook Japan and New Zealand, predicting where and when the next big seismic event will happen is a holy grail to seismologists. These two stories show two methods of reaching it: The first delves into sci-fi that may pave the way in the future, the other looks at methods already used.
Story 1: Scientists hope to drill further into the Earth than ever before.
The goal of drilling down into through the Earth’s crust to take a sample of the mantle has been a goal for many years. The last major attempt was Project Mohole which was called off in the 1960s due to the mounting difficulties and escalating cost.
However, due to better knowledge of the structure of the crust and advances in technology, it looks more than likely that this may become a reality in as early as 2020.
I have uploaded a PowerPoint presentation that introduces the story and contains a few questions that would be a useful starter to a revision lesson on the structure of the Earth.
The last slide asks ‘would drilling this hole create an enormous eruption?’ This will encourage students to use their knowledge of what a volcanic eruption is and the properties of the mantle to discuss together their thoughts.
You can ask higher ability students to discuss why scientists want to study a sample of the mantle. This layer plays a major role in plate tectonics so insight into processes within the mantle will help us better understand earthquakes, tsunamis and volcanoes and possibly bring us a step closer to be able to predict when they will happen.
Other reasons include:
– A sample of the mantle will tell us much about the Earth’s origins and history, including a possible insight into how life started as scientists will be able to look for signs of life in the deep crustal rocks. Microbial activity has been detected up to 120 °C so maybe life exists at temperatures even hotter than this.
– Scientists would be drilling through the transitional layer between the crust and the mantle – the Moho layer. This would give a chance to study this mysterious zone.
Another way to use this story is as an interesting introduction to a lesson on how scientists first theorised the internal structure of the Earth by analysing seismic waves. This next step in our understanding will be the first time that scientists have been able to use actual evidence – a rock from the mantle – to prove these predictions are correct.
Scathing commentary about the move ‘The Core’ in which a team drill through to the core of the Earth. If you are able to watch clips from the DVD in class your students will be able to pick up on the extremely ‘bad science’ it contains – including the part where they enter a void inside the Earth and are able to get out of their vehicle and wonder about!
Article about the possible drilling attempt from National Geographic.
Story 2 – Studying the Nyiragongo Volcano
Another article from National Geographic discusses the fascinating world of the volcanologist. A team have recently returned from the Nyiragongo Volcano in the Democratic Republic of the Congo.
This volcano is in the Great Rift Valley, where the African continental plate is being wrenched apart. In this earlier post I discussed the Afar region in Ethiopia where a new sea is slowly being created because of the active plate movement in this area.
Nyiragongo is one of the most active volcanoes in the world but also one of the least studied. This is due to the politically volatile country in which it lies. Its fertile slopes have led a vibrant city to grow beneath its base: Goma is now home to around a million people, and its population is growing. The team studying Nyiragongo were looking for clues as to when the volcano will next erupt.
Studying the activity in this area would make an interesting case-study about volcanoes.
The National Geographic article covers some interesting information on the kinds of data that the team collect in order to predict volcanic eruptions including taking measurements of the mountain, analysing gases and taking samples of lava. There are some amazing photographs of the team at work in this extremely dangerous location.
Students can discuss why so many people live around the volcano even though it is one of the most dangerous places in the world to live. This can leads on to a discussion about why monitoring the volcano is so important.
Volcanic activity in this area has further consequences as it could cause the release of huge amounts of methane and carbon dioxide from the nearby lake – Kivu. One of only three ‘exploding lakes’ in the world, Kivu is the largest and potentially the most dangerous. A volcanic interaction would heat the water at its base forcing out the methane which could cause an explosion, and trigger the release of carbon dioxide. The carbon dioxide would then suffocate large numbers of people in the lake basin as the gases roll off the lake surface. It is also possible that the lake could spawn tsunamis as gas explodes out of it.
This would be a nice real-life link into any lesson looking at carbon dioxide. The fact that it is a dense gas which excludes oxygen is the reason why it is used in fire extinguishers, and why a blanket of it covering a city would be so toxic. Students could also be asked to look at the tragic event in 1986 at another ‘exploding lake’ – Nyos in Cameroon when 1 700 people suffocated when carbon dioxide escaped from the lake.
Interactive image which contains information on the volcanic activity in the area and how the volcano and lake Kivu are connected.
The article from National Geographic about Nyiragongo.