In 2012, CM, in a former guise, wrote a piece on what might happen if Mt Fuji erupted. Over the past couple of years, scientists have been postulating whether Yellowstone might blow her top. In 2019 the stories are front page news again. The last time she blew was 631,000 years ago. So the consensus is not if, but when. The last time she blew, 240 cubic miles of volcanic ash spewed into the atmosphere. When Mt St Helens erupted as a VEI5 (paroxysmal), 0.29 cubic miles of ash and volcanic rock was sent into the atmosphere. The 2010 Icelandic Eyjafjnallajokull volcano was a VEI4 (cataclysmic).
The doomsayers suggest if the Wyoming based volcano goes off, 87,000 will be killed immediately and 2/3rds of the US will become inhabitable. The ash would block out sunlight leading to cooling by up to 5 degrees. The sulphur aerosol spewed out of volcanoes reflects sunlight meaning the world could be thrown into a nuclear winter. A volcano erupting has zero to do with global warming but it would change climactic conditions.
The damage caused in each zone can be seen here. FEMA believe a $3 trillion minimum economic impact would occur. That seems light if the Mega-colossal (VEI8) event occurs. St. Helens was around $3 billion in damages.
A major problem faced after an eruption is the electricity grid. Dry volcanic ash in and of itself is not conductive enough to cause insulator flashovers but it is highly soluble and if it is mainly composed of aerosols it can cause the grid to be shutdown. The insulators require de-ionised water to clean at low pressure to prevent damage to the surfaces of the conductors. Trying to rectify the problem by using backup diesel generators would be met by ultra fine volcanic ash particles gumming up injectors and the engine filters. So power shortages would be long lasting. Solar would also require cleaning and wind power gears would also become fouled up by the ash. So if you own a Tesla you’ll be in trouble. Gasoline powered cars would eventually stop working if filters weren’t replaced frequently.
Water reservoirs would also end up making it unsuitable for drinking in the short term. Depending on the level of turbidity of the water supply, several weeks may be required to restore it to normal.
Airlines would be grounded. Volcanic ash is terminal for jet engines. In 2010, the Icelandic volcano cost airlines over $1.5 billion in revenue over the 6 weeks or so of disruption. The Eurostar was not impacted by the volcano and saw a large uptick in business. Ferries also experienced a 4x boost in traffic.
If the eruption was as huge as forecast, filter companies would stand to benefit greatly. High Efficiency Particulate Air (HEPA) filters would see high replacement demand. Japanese company Daikin (6367) has a subsidiary Nippon Muki which makes HEPA filters. Japan Vilene (3514) is also a maker for automotive related filters. Dow Chemical has HEPA filters although a tiny part of the total business.
Shipping companies would benefit, especially transport substitution of air cargo players where fleets would not be able to be deployed.
Insurance companies would likely escape a lot of financial damage as their policies are unlikely to cover ‘acts of god’ such as volcanic eruptions.
EPCO losses would be immense. The amount of repair work to entire grids and a halt to power supplies would hit revenue and ramp cost.
While it is still only hypothetical, the tragedy of a mega colossal eruption would be catastrophic in terms of loss of life and economic impact. The US is 25% of world GDP. Such a VEI8 eruption would have severe global economic implications. So if it comes, batten down the hatches.