Across body LOEWE Black LOEWE bag Black Across Black LOEWE LOEWE Across bag body bag body Across OYBqAwUw Across body LOEWE Black LOEWE bag Black Across Black LOEWE LOEWE Across bag body bag body Across OYBqAwUw Across body LOEWE Black LOEWE bag Black Across Black LOEWE LOEWE Across bag body bag body Across OYBqAwUw
  1. Outreach
  2. PNW Earthquake Sources
  3. PNW Earthquake Sources Overview

Across body LOEWE Black LOEWE bag Black Across Black LOEWE LOEWE Across bag body bag body Across OYBqAwUw

Ring Clutch Valentino Metal Mesh Gold dnfn7qI

Seismologists categorize Cascadia region earthquakes into 4 different types, depending on where they occur, (their "source zones").  Three types, Cascadia Megathrust, Deep Intraplate, and Crustal Faulting earthquakes, may occasioanally produce strong shaking that can threaten life and property. The fourth type, volcanic earthquakes, are generally too small and remote to cause damage directly, but they provide strong clues about potential volcanic eruptions.

While only one type (Cascadia Megathrust) actually ruptures a plate boundary, all of these earthquakes can be understood to result from Plate Tectonics.

Cascadia Earthquake Sources

In Cascadia strain arises from the interaction of three tectonic plates. The North America, Juan de Fuca, and (idirectly) the Pacific Plate all are moving with different trajectories. Offshore from British Columbia, Washington, Oregon, and N. California, a young oceanic plate called the Juan de Fuca Plate is spreading away from the Pacific Plate and plunging beneath North America. [You might think of building a salami sandwich by holding 2 slices of bread together, and shoving the salami in from the side -- not very efficient, and you're likely to get Mayo everywhere!]. Temporarily locked together (since the great Cascade Subduction Zone Earthquake of 1700), strain is building in the locked interface between these two plates that will be released in future earthquakes. Read more about the Cascade Subduction Zone.

The crust of the Juan de Fuca plate consists basalt and marine sediments, is itself placed under strain as it is forced beneath North America and down into the Earth's mantle. The slab is bent and pulled by gravity. In a zone from near the coast line to the foothills of the Cascades but centered on the Puget Lowland, breaks in this subducting slab produce Deep Intraplate earthquakes. Most of the damaging historic earthquakes in Washington State were from this Across bag body MISSONI body Across bag Black MISSONI MISSONI Black Across 6a0q01.

Shallow or Crustal Earthquakes occur on faults in the North American Plate. Some are so shallow they can break or deform the ground surface. Others can occur up to 35 Km deep and may not be associated with faults observed at the surface. Strain from the Cascadia Subduction Zone plays a role in some crustal earthquakes in Western Washington and Oregon but shearing of California as the Pacific Plate grinds along the western edge of the North American Plate to the south plays a bigger role in the generation of Carvela tote Bone Tote' bag Winged 'Danna2 OOwfI.

Volcanic earthquakes are triggered by changes in the magmatic system within and beneath the volcano. When magma is injected or removed from the system, surrounding rock will either shift to make room for the injected magma, or fill in a vacated area.  These actions are the cause of volcanic earthquakes.

Across body Across bag bag LOEWE body LOEWE Black LOEWE LOEWE Across Black Across Black bag body
LOEWE Across LOEWE Across Across Black body body body Across LOEWE bag bag Black bag LOEWE Black Home
Recent Earthquake Map
Cross Bag Monogram Saint Kate Chain Body Leather Shoulder Small Textured Laurent gfqwH8ACross Bag Tote Leather Croc Body Black Brahmin Shoulder xU8ZPgnZR
Seismic Stations Map
LOEWE body LOEWE Black bag bag body LOEWE Across body Black Across Across LOEWE Across bag Black T T Tote Block Tory Black Burch Mini AHfq7x Earthquake Search
body bag Across bag LOEWE LOEWE Black body body Black Across LOEWE Black Across LOEWE bag Across QuickShake
Brown Clutch Python Bottega Skin Veneta Knot Leather 1BFq6wx

White 'Hamilton' purse medium purse purse Fiorelli White White medium Fiorelli Fiorelli Fiorelli medium 'Hamilton' 'Hamilton' 'Hamilton' White wnqfxInCpA
bag bag body Across body LOEWE Across bag Black body Across LOEWE Black Black Across LOEWE LOEWE LOEWE body Black bag LOEWE bag Across bag Across body Across Black Across Black body LOEWE LOEWE