Increase in Powerful Quakes May Be Related To Ice Sheets Getting “Lighter” and More Extreme Storms
Think of the Earth As A Giant Plastic Ball And Everything Starts To Make Sense
The planet Earth is changeable and inherently unstable. Whenever stress is applied to one component of the complex interlocking geophysical system we call home (for now) has unpredictable consequences. After three powerful earthquakes and a new volcano eruption within a few weeks of each other*, we are reminded of a topic we have broached here before, but is worth discussion again.
ICE SHEET COLLAPSE ALLOWS CRUST TO SPRING BACK
There are two main ice sheets on the planet, one in Greenland and the other in Antarctica. Together they hold enough ice to raise global sea levels at least 50 feet if all the ice melts. But that is not our concern in this article. But it is our concern that this land-based ice is melting at an unprecedented rate.
The Greenland ice sheet is between 6,600 – 9,800 ft thick (2,000 – 3,000 m) and covers 660,000 sq mi. The Antarctic ice sheet is is almost 5.4 million sq mi and contain about 7.2 million cubic MILES of ice. This ice mass sits on land and is phenomenally heavy. In Greenland, for example, it has pressed the interior of the island about 1,000 ft below sea level.
When the total weight of this ice mass on top of the land changes, the earth’s crust rises. This causes stress changes that telegraph around the globe. Whenever underground pressures change near faults, earthquakes can happen.
In September 2016, researchers from the Technical University of Denmark published a new paper in Science Advances suggesting that the ability of the Earth’s crust in Greenland’s to snap back when the ice is removed has been underestimated. Remember that the Earth’s crust is on 5 to 30 miles thick. In some areas, the land is rising at a rate of 1/2″ in year.
SWELLING OCEAN VOLUME AND STORMS
Another way the geosphere interacts with global warming driven effects is in the context of increasing ocean volume. While most people are aware that the seas are rising globally due to ice melt, not everyone understands that the actual volume of the ocean is expanding due to warmer water. This is simply a matter of physics. However, the increase in ocean volume further destabilizes the geosphere, creating the possibility that more fault lines will be triggered. A fault that is unstable can be prepared to a coiled spring. It does not take much change in pressure to release its energy.
MORE EXTREME WEATHER EVENTS
This cause and effect scenario is less obvious than the first two, but has also been discussed in a serious way by earth scientists. This theory suggests that powerful typhoons can activate faults due to reduced atmospheric pressure as the storm passes over land. The change in pressure can release accumulated stress as it interacts with the terrain.
* Japan, New Zealand and Italy.