Since we are on the topic of volcanoes lately, I question what could possibly influence these eruptions. Besides the melting of rock and shifting of magma chambers beneath our feet, I wonder if our impact on the atmosphere could possibly make a difference to what happens to volcanoes. Many people doubt that the changes we make to our atmosphere would make any difference to the processes that only “mother nature” causes. When looking at articles on New Scientists, I came across one article that actually says that the result of our existence actually can be a catalyst or may trigger earthquakes and volcanoes.
In the article, the author repeatedly says that the Earth’s crust is very sensitive and that the slightest changes in weather and climate has the ability to rip the planet’s crust apart, unleashing the furious might of volcanic eruptions, earthquakes and landslides. One of the biggest impacts of global warming is the melting of ice caps causing an increase in the sea level. Storms of all kinds are becoming more violent and frequent. The El Nino seasons are becoming more common and are lasting longer. This means that El Nino raises the local sea level by a few tens of centimetres, and scientists believe the extra water weight may increase the pressure of fluids in the pores of the rock beneath the seabed. This might be enough to counteract the frictional force that holds the slabs of rock in place, making it easier for faults to slip. These changes might seem tiny but in reality that have a substantial effect.
In the past 300 years scientists have found that there are around 20% more eruptions worldwide during the northern hemisphere’s winter than the summer. The reason may be that global sea level drops slightly during the northern hemisphere’s winter. Because there is more land in the northern hemisphere, more water is locked up as ice and snow on land than during the southern hemisphere’s winter.
Perhaps the greatest geological hazards during climate change will be the result of melting ice sheets. Apart from the risk that loose sediments exposed by melted ice could slip into the sea as tsunami-generating landslides, the removal of heavy ice could also trigger volcanic eruptions. For example, Iceland’s Vatnajokull ice cap sits over a plate boundary and several volcanoes. That ice is likely to disappear within the next two centuries. In the wake of the last ice age, volcanism was up to 30 times greater in northern Iceland compared with today
We have to think of ways to stop this progressing climate change, and one of the new ideas that there has been lately is carbon sequestration. Many people believe that this will bring carbon dioxide out of the air and safely put it into the Earth’s crust. But in reality there is a flaw that relates to an increase in earthquakes. In a carbon sequestration power plant (CCS), carbon dioxide is extracted from the exhaust then pumped into aquifers and old gas fields several kilometres beneath the Earth’s surface. But the CO2 expands as it rises through the porous rock, increasing pressure inside. If enough of this CO2 is injected into an aquifer or into the crust, it could cause an increase in the pressure enough to reactivate a fault and trigger an earthquake. Another negative result from CCS is that the chemical reactions between the injected CO2, water and rock could also destabilise the rock causing more problems to the Lithosphere. A CCS facility at the Sleipner gas field in the North Sea, may have triggered a magnitude 4 earthquake in 2008. Had it been bigger, it might have triggered a tsunami.