11 months ago
A monolithic 7.8-magnitude 'megaquake' rocked nan Seattle area 1,100 years agone erstwhile 2 responsibility lines ruptured simultaneously - and experts fearfulness it could hap again.
The faults are located successful Puget Sound, which contains Seattle, Tacoma and Olympia, and person ruptured successful nan past, but nan ancient tremor was 30 times much powerful than existent informing signs propose is imaginable from nan responsibility zones.
A squad of scientists led by nan University of Arizona uncovered nan earthy disaster, determining it triggered landslides and a section tsunami that would beryllium catastrophic if it deed nan region, location to much than 4 cardinal group today.
A 2005 script recovered that moreover a magnitude 6.7 earthquake would termination much than 1,600 people, destruct astir 10,000 buildings and nutrient full economical losses of $50 billion.
A squad of scientists led by nan University of Arizona uncovered nan earthy disaster, determining it triggered landslides and a section tsunami that would beryllium catastrophic if it deed nan region - location to much than 4 cardinal group today
The responsibility lines successful mobility are the Seattle Fault Zone (SFZ), located beneath and astir nan city, and different from nan Saddle Mountain Fault Zone (SMFZ) successful southwest Washington.
Researchers pulled fossilized Douglas-fir trees from six Puget Sound sites associated pinch nan Seattle and Saddle Mountain responsibility zones, which were believed to person been destroyed by seismic activity.
The squad past measured radiocarbon concentrations successful nan wood, allowing them to pinpoint nan twelvemonth each character fell from its roots.
All nan trees were killed wrong six months, betwixt 923 and 924.
These findings explicate 2 scenarios that could person happened.
The faults are located successful Puget Sound, which contains Seattle, Tacoma and Olympia, and person ruptured successful nan past, but nan ancient tremor was 30 times much powerful than existent informing signs propose is imaginable from nan responsibility zones
In these first cases, nan 2 faults ruptured arsenic 2 earthquakes separated by hours to months - the Seattle responsibility area had a 7.5 magnitude earthquake, and the Saddle Mountain responsibility area had a 7.3 magnitude quake.
'The 2nd anticipation is simply a single, larger, multifault earthquake rupturing some nan Seattle and Saddle Mountain responsibility zones pinch a median magnitude estimated astatine a magnitude of 7.8,' nan study published successful Science Advances reads.
The squad noted successful nan study that simultaneous ruptures had occurred elsewhere successful our modern world, including a 2001 7.9 magnitude quake in southern Alaska, a 1992 7.3 magnitude successful Southern California and a 7.8 magnitude earthquake that deed New Zealand successful 2016 - but this arena progressive much than 20 chopped faults.
In nan lawsuit of Puget Sound, scientists judge nan 2 faults whitethorn beryllium kinematically connected.
A 2022 study by researchers from nan Washington State Department of Natural Resources besides looked astatine a megaquake hitting Seattle, but this 1 was only a 7.5-magnitude.
The exemplary showed that 42-foot waves would engulf nan metropolis wrong 3 minutes.
The 42-foot waves would swirl astir nan landmark Seattle Great Wheel, reaching inland arsenic acold arsenic Lumen Field stadium, location of nan Seattle Seahawks, and T-Mobile Park, wherever nan Seattle Mariners shot squad plays.
Thirty miles southbound of downtown, nan larboard of Tacoma could spot waves scope arsenic acold arsenic 3 miles inland.
