A 700-mile-long fault line that runs along the West Coast is overdue for a massive earthquake that scientists warn could sink parts of the US.
New research found that a 8.0 magnitude or higher quake along the Cascadia Subduction Zone, combined with rising sea levels, would cause coastal land to sink up to 6.5 feet within 30 minutes of a major tremor.
The team generated tens of thousands of earthquake models to estimate the potential range of earthquake-driven subsidence — sinking land — that can be expected from the next large Cascadia earthquake.
They determined that the most severe effects would hit southern Washington, northern Oregon and northern California, densely populated areas in the region.
This event would result in significant expansion of the coastal floodplain — an area with a one percent chance of flooding each year — increasing it from 35 square miles to 116.
If such a quake struck today, the researchers estimate that an additional 14,350 residents, 22,500 structures and 777 miles of roadway would fall within the post-earthquake floodplain, more than doubling flood exposure.
The Cascadia Subduction Zone has historically produced 8.0 or larger magnitude earthquakes every 400 to 600 years, with the last striking in 1700.
This suggests the ‘sleeping giant’ is poised for another big one soon.
A 700-mile-long fault line that runs along the West Coast is overdue for a massive earthquake that scientists warn could sink parts of the US (STOCK)
Sea level rise driven by climate change would ‘amplify’ the ground sinking and trigger a major Cascadia earthquake, according to the researchers.
The Intergovernmental Panel on Climate Change (IPCC) estimates that sea levels along this subduction zone could be up to three feet higher by 2100.
‘Today, and more so in 2100 as background sea levels rise, the immediate effect of earthquake-driven subsidence will be a delay in response and recovery from the earthquake due to compromised asset,’ said Tina Dura, lead researcher and assistant professor of geosciences at Virginia Tech, in a statement.
‘Long-term effects could render many coastal communities uninhabitable,’ she added.
After generating numerous models to estimate the Cascadia’s potential to cause earthquake-driven ground sinking, Dura and her colleagues used geospatial analysis to estimate the expansion of the floodplain.
This technique uses maps and location data to measure how land, water or cities might be affected by events such as earthquakes or climate change.
In this case, the researchers applied it to figure out how much more land would be vulnerable to flooding after a major Cascadia earthquake.
Because they can’t be sure when the next large quake will occur, the team modeled the impacts of two different scenarios: an earthquake striking today, and in 2100.
The Cascadia zone, which sits under Washington, Oregon, and northern California, is said to be ‘overdue’ for another major earthquake
If such a quake struck today, the researchers estimate that an additional 14,350 residents, 22,500 structures and 777 miles of roadway would fall within the post-earthquake floodplain, more than doubling flood exposure. Pictured: flooding in Washington State
If the quake happened today, flood exposure would double, exposing thousands of residents, structures and hundreds of miles of roadways to greater risk of flooding.
But this event would also affect five airports; 18 critical facilities such as schools, hospitals and police stations; eight wastewater treatment plants; one electric substation and 57 potential contaminant sources, including animal feeding operations, gas stations and solid waste facilities.
By 2100, a large Cascadia earthquake would triple flood exposure in affected areas of the West Coast, expanding the floodplain by up to 142 square miles.
In both the present-day and future impact scenarios, damage to farm will result in ‘heavy economic loss’ as ocean water contaminated soils with salt and renders them ‘unusable,’ according to the researchers.
Such an event would also wreak havoc on ecosystems, especially coastal estuaries, intertidal wetlands and protective sand dunes and beaches.
Losing these natural land features could make flooding even worse, the researchers say. That’s because they as they ‘act as buffers against storm surges,’ preventing coastal erosion and property damage.
The team published their findings in the journal Earth, Atmospheric and Planetary Sciences.
The Cascadia Subduction Zone isn’t the only place where something like this could happen.
There are 28 active subduction zones around the world, which suggests that the study’s findings could help inform hazard assessments and flood mitigation strategies for seismically active regions worldwide, Dura said.
This article was originally published by a www.dailymail.co.uk . Read the Original article here. .