1700 Cascadia earthquake

Cascadia earthquakeCascadia earthquake of 17001700Cascadia earthquake on January 26, 17001700-01-261700 Cascadia (M9.0)1700 CECascadia earthquake of 26 January 1700January 26, 1700tsunami
The 1700 Cascadia earthquake occurred along the Cascadia subduction zone on January 26 with an estimated moment magnitude of 8.7–9.2.wikipedia
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Cascadia subduction zone

CascadiaCascade subduction zoneCascadia Abyssal Plain
The 1700 Cascadia earthquake occurred along the Cascadia subduction zone on January 26 with an estimated moment magnitude of 8.7–9.2.
There are no contemporaneous written records of the 1700 Cascadia earthquake.

Megathrust earthquake

megathrustmegathrust typemegathrust earthquakes
The megathrust earthquake involved the Juan de Fuca Plate from mid-Vancouver Island, south along the Pacific Northwest coast as far as northern California.
This subduction zone was responsible for the 1700 Cascadia earthquake.

Vancouver Island

Vancouver Island, British ColumbiaWest Coast of Vancouver IslandNorthern Vancouver Island
The megathrust earthquake involved the Juan de Fuca Plate from mid-Vancouver Island, south along the Pacific Northwest coast as far as northern California.
The area has been known to host megathrust earthquakes in the past, the last occurring in 1700.

First Nations

First NationNorth American IndianIndian
Local Native American and First Nations groups residing in Cascadia used oral tradition to transmit knowledge from one generation to the next, so there is no written documentation like with Japanese tsunami.
Some of their oral traditions accurately describe historical events, such as the Cascadia earthquake of 1700 and the 18th-century Tseax Cone eruption.

Oregon

ORState of OregonOregon, USA
The most important clue linking the tsunami in Japan and the earthquake in the Pacific Northwest comes from studies of tree rings (dendrochronology), which show that several "ghost forests" of red cedar trees in Oregon and Washington, killed by lowering of coastal forests into the tidal zone by the earthquake, have outermost growth rings that formed in 1699, the last growing season before the tsunami.
The most recent major activity was the 1700 Cascadia earthquake.

Bridge of the Gods (land bridge)

Bridge of the GodsBonneville SlideBridge of the Gods (geologic event)
The earthquake caused a tsunami which struck the coast of Japan and may also be linked to the Bonneville Slide and the Tseax Cone eruption in British Columbia.
These younger radiocarbon ages permitted a possible link to the 1700 Cascadia earthquake.

Miyako, Iwate

MiyakoMiyako cityMiyako Bay
The Japanese records exist primarily in the modern-day Iwate Prefecture, in communities such as Tsugaruishi, Kuwagasaki and Ōtsuchi.
On 27 January 1700, the coast of Miyako was hit by a 3 m tsunami that was a product of the 1700 Cascadia earthquake, destroying 20 homes.

Juan de Fuca Plate

Juan de FucaJuan de Fuca tectonic plateJuan de Fuca oceanic plate
The megathrust earthquake involved the Juan de Fuca Plate from mid-Vancouver Island, south along the Pacific Northwest coast as far as northern California.
The last megathrust earthquake at the Cascadia subduction zone was the 1700 Cascadia earthquake, estimated to have a moment magnitude of 8.7 to 9.2.

Tseax Cone

The earthquake caused a tsunami which struck the coast of Japan and may also be linked to the Bonneville Slide and the Tseax Cone eruption in British Columbia.
It has recently been suggested that the Tseax eruption was related to the Cascadia earthquake of 26 January 1700.

Iwate Prefecture

IwateIwate, JapanIwate-ken
The Japanese records exist primarily in the modern-day Iwate Prefecture, in communities such as Tsugaruishi, Kuwagasaki and Ōtsuchi.
In 1700, a tsunami from the 1700 Cascadia earthquake struck Iwate Prefecture.

2004 Indian Ocean earthquake and tsunami

2004 Indian Ocean earthquake2004 Indian Ocean tsunami2004 tsunami
As seen in the 1700 quake, the 2004 Indian Ocean earthquake, and the 2011 Tōhoku earthquake and tsunami, subduction zone earthquakes can cause large tsunamis, and many coastal areas in the region have prepared tsunami evacuation plans in anticipation of a possible future Cascadia earthquake.
Other very large megathrust earthquakes occurred in 1868 (Peru, Nazca Plate and South American Plate); 1827 (Colombia, Nazca Plate and South American Plate); 1812 (Venezuela, Caribbean Plate and South American Plate) and 1700 (western North America, Juan de Fuca Plate and North American Plate).

Seattle

Seattle, WashingtonSeattle, WACity of Seattle
However, the major nearby cities, notably Seattle, Portland, Vancouver, Victoria, and Tacoma, which are located on inland waterways rather than on the coast, would be sheltered from the full brunt of a tsunami.
Other strong quakes occurred on January 26, 1700 (estimated at 9 magnitude), December 14, 1872 (7.3 or 7.4), April 13, 1949 (7.1), and April 29, 1965 (6.5).

Huu-ay-aht First Nations

Huu-ay-ahtHuu-ay-aht First Nation
The Huu-ay-aht legend of a large earthquake and ocean wave devastating their settlements at Pachina Bay, for instance, speaks of the event taking place on a winter evening shortly after the village's residents had gone to sleep.
This oral tradition concurs with scientific research into the timing of the 1700 Cascadia earthquake.

Pacific Northwest Seismic Network

Pacific Northwest Seismograph Network
Damaging earthquakes are well known in the Pacific Northwest, including several larger than magnitude 7, most notably the M9 1700 Cascadia earthquake and the M7.0–7.3 earthquake in about 900AD on the Seattle Fault.

Geology of the Pacific Northwest

Geology of OregonGeology of WashingtonPacific Northwest
The Juan de Fuca Plate is capable of producing megathrust earthquakes of moment magnitude 9: the last such earthquake was the 1700 Cascadia earthquake, which produced a tsunami in Japan, and may have temporarily blocked the Columbia River with the Bonneville Slide.

1949 Queen Charlotte Islands earthquake

1949 Queen Charlotte earthquakeQueen Charlotte earthquake1949
However, the greatest earthquake in Canadian history was the 1700 Cascadia earthquake, a megathrust earthquake that occurred along the Pacific Northwest coast from Northern California to southwestern British Columbia which reached magnitude 9 on the Richter magnitude scale.

Neskowin Ghost Forest

These ghost forests are evidence of significant, rapid changes in coastline – often due to seismic events such as the 1700 Cascadia earthquake.

Moment magnitude scale

moment magnitudeM w magnitude
The 1700 Cascadia earthquake occurred along the Cascadia subduction zone on January 26 with an estimated moment magnitude of 8.7–9.2.

Pacific Northwest

northwestNorthwest CoastPacific Northwest Coast
The megathrust earthquake involved the Juan de Fuca Plate from mid-Vancouver Island, south along the Pacific Northwest coast as far as northern California.

Northern California

NorthernNorth CaliforniaNorCal
The megathrust earthquake involved the Juan de Fuca Plate from mid-Vancouver Island, south along the Pacific Northwest coast as far as northern California.