California Drifting

I would not want to be living in California right now.  I understand residents there take "everyday" earthquakes with equanimity.  I don't know how they deal with the possibility of The Big One.  I have signed on for e-mailed Fox News updates.  I'm not sure how or why this occurred.  If I had television I would not watch Fox, but these little headlines are free from political overtones and do serve to keep me informed between forays to the AP wire service site. 

The last several weeks there have been numerous news blips about earthquakes.  I think I probably started to pay attention when the Oregon quake occurred.  My brother and his family live in Washington state.  Then there have been at least a couple off the coast of Mexico.  A blogger whose blog I follow is vacationing in Mexico.  Although I think she's on the Atlantic side, those notices caught my attention.  The only time I vacationed in Mexico I experienced a quake, probably minor by their standards, but our guide ran into the store where my sister and I were shopping and escorted us out into the plaza.  The only other earthquake I've experienced was in, believe it or not, Columbia, Missouri.  That was in 1965 or 1966 and would have been the New Madrid Fault.  I thought someone was blasting.  I recall it was between 4.00 and 5.00 on the Richter Scale.  Then there was one in Chile yesterday, I think, and now today one in New Guinea, the general area, I think, where this latest lot started.

I thought perhaps I was overreacting, so just out of curiosity decided to look up all of the earthquakes in the last 30 days that were over 5.1 on the Richter.

5.6 l'esperance rock, new zealand

6.8 lae, papua new guinea

5.1 hacienda la calera, chile

6.7 hacienda la calera, chile

5.1 banda aceh, indonesia

5.3 malili, indonesia

5.2 off the west coast of northern sumatra

5.5 methoni, greece

5.3 off the west coast of northern sumatra

5.8 malili, indonesia

6.2 off the west coast of northern sumatra

6.5 isangel, vanuatu

5.5 visokoi island,

5.9 tugu hilir, indonesia

5.3 off the west coast of northern sumatra

5.6 severo-kuril'sk, russia

5.1 off the west coast of northern sumatra

6.2 drake passage

5.3 santiago pinotepa nacional, mexico

5.4 santiago pinotepa nacional, mexico

5.7 iwaki, japan

5.1 off the west coast of northern sumatra

5.6 namie, japan

5.3 off the west coast of northern sumatra

5.3 iwaki, japan

5.1 off the west coast of northern sumatra

6.9 santa isabel, mexico

6.2 santa isabel, mexico

5.5 north indian ocean

6.5 arteaga, mexico

5.4 north indian ocean

5.9 bandon, oregon

5.5 off the west coast of northern sumatra

5.4 off the west coast of northern sumatra

5.1 off the west coast of northern sumatra

5.1 off the west coast of northern sumatra

5.1 off the west coast of northern sumatra

5.3 north indian ocean

5.3 north indian ocean

5.1 north indian ocean

5.2 off the west coast of northern sumatra

5.5 north indian ocean

5.3 off the west coast of northern sumatra

5.1 off the west coast of northern sumatra

5.1 off the west coast of northern sumatra

5.1 off the west coast of northern sumatra

5.1 off the west coast of northern sumatra

5.7 north indian ocean

5.3 north indian ocean

5.4 off the west coast of northern sumatra

5.4 visokoi island,

8.2 off the west coast of northern sumatra

5.4 north indian ocean

5.4 off the west coast of northern sumatra

5.1 off the west coast of northern sumatra

5.3 off the west coast of northern sumatra

5.3 off the west coast of northern sumatra

6.0 north indian ocean

5.5 adak, alaska

8.6 off the west coast of northern sumatra

5.3 saumlaki, indonesia

5.1 southern mid-atlantic ridge

5.2 southern mid-atlantic ridge

5.8 north of ascension island

5.3 hualian, taiwan

5.2 saumlaki, indonesia

5.3 kandrian, papua new guinea

5.5 sungaipenuh, indonesia

6.1 taron, png

5.3 rabaul, papua new guinea

5.4 dobo, indonesia

5.3 taron, png

5.2 iquique, chile

5.4 piura, peru

5.1 san antonio, chile

6.0 cuajinicuilapa, mexico

5.4 hihifo, tonga

5.3 ometepec, mexico

5.7 taron, png

5.7 iwaki, japan

5.4 tristan da cunha region

5.2 pangai, tonga

5.2 south of the fiji islands

5.2 banda aceh, indonesia

5.2 panguna, papua new guinea

5.4 puerto madero, mexico

5.1 kushiro, japan

5.3 ndoi island, fiji

5.1 namie, japan

5.3 southwest indian ridge

5.2 bengkulu, indonesia

5.5 pacific-antarctic ridge

6.1 miyako, japan

6.0 northern east pacific rise

5.5 northern east pacific rise

5.6 southwest indian ridge

5.2 bulanik, turkey

5.3 lorino, russia

7.1 talca, chile

5.1 ndoi island, fiji

I'd like to post the map from the U.S. Geological Survey, which not only really brings home the number of earthquakes that never make the news, but highlights those occurring along the Pacific Coast of the United States in the last 30 days since none of these seems to have made the cut.  Seems as if it can't be done or I don't know how to do it, so you'll just have to go to this link:  http://earthquake.usgs.gov/earthquakes/recenteqsww/

I thought I'd look up the tectonic plate involved in so many of these recent earthquakes.  I was at first wondering if most of this activity is related to what is called the Pacific Plate, the large pale yellow plate, but it's much more complicated than that. 

Here is what Wikipedia has to say:  The Pacific Ring of Fire (or just The Ring of Fire) is an area where a large number of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean. In a 40,000 km (25,000 mi) horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements. The Ring of Fire has 452 volcanoes and is home to over 75% of the world's active and dormant volcanoes.^[1] It is sometimes called the circum-Pacific belt or the circum-Pacific seismic belt.

Eruption of Mount St. Helens on July 22, 1980.

 

About 90%^[2] of the world's earthquakes and 81%^[3] of the world's largest earthquakes occur along the Ring of Fire. The next most seismic region (5–6% of earthquakes and 17% of the world's largest earthquakes) is the Alpide belt, which extends from Java to Sumatra through the Himalayas, the Mediterranean, and out into the Atlantic. The Mid-Atlantic Ridge is the third most prominent earthquake belt.^[4][5]
The Ring of Fire is a direct result of plate tectonics and the movement and collisions of lithospheric plates.^[6] The eastern section of the ring is the result of the Nazca Plate and the Cocos Plate being subducted beneath the westward moving South American Plate. The Cocos Plate is being subducted beneath the Caribbean Plate, in Central America. A portion of the Pacific Plate along with the small Juan de Fuca Plate are being subducted beneath the North American Plate. Along the northern portion the northwestward moving Pacific plate is being subducted beneath the Aleutian Islands arc. Further west the Pacific plate is being subducted along the Kamchatka Peninsula arcs on south past Japan. The southern portion is more complex with a number of smaller tectonic plates in collision with the Pacific plate from the Mariana Islands, the Philippines, Bougainville, Tonga, and New Zealand; this portion excludes Australia, since it lies in the center of its tectonic plate. Indonesia lies between the Ring of Fire along the northeastern islands adjacent to and including New Guinea and the Alpide belt along the south and west from Sumatra, Java, Bali, Flores, and Timor. The famous and very active San Andreas Fault zone of California is a transform fault which offsets a portion of the East Pacific Rise under southwestern United States and Mexico. The motion of the fault generates numerous small earthquakes, at multiple times a day, most of which are too small to be felt.^[7][8] The active Queen Charlotte Fault on the west coast of the Queen Charlotte Islands, British Columbia, Canada, has generated three large earthquakes during the 20th century: a magnitude 7 event in 1929, a magnitude 8.1 occurred in 1949 (Canada's largest recorded earthquake) and a magnitude 7.4 in 1970.^[9]

...Earthquake activity in Chile is related to subduction of the Nazca Plate to the east. Chile notably holds the record for the largest earthquake ever recorded, the 1960 Valdivia earthquake. Villarrica, one of Chile's most active volcanoes, rises above Villarrica Lake and the town of Villarrica. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km wide caldera formed during the late Pleistocene, >0.9 million years ago.

Llaima's 2008 eruption

 

A 2-km-wide postglacial caldera is located at the base of the presently active, dominantly basaltic-to-andesitic cone at the NW margin of the Pleistocene caldera. About 25 scoria cones dot Villarica's flanks. Plinian eruptions and pyroclastic flows have been produced during the Holocene from this dominantly basaltic volcano, but historical eruptions have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Lahars from the glacier-covered volcano have damaged towns on its flanks.
In 2008, Chile experienced two volcanic eruptions, the first one from Llaima Volcano (January 1) and Chaitén Volcano (May 1). More recently, an 8.8-magnitude earthquake struck central Chile on February 27, 2010 (2010 Chile earthquake).^[10]

...Mexico

The Trans-Mexican Volcanic Belt

 

Volcanoes of Mexico are related to subduction of the Cocos and Rivera plates to the east, which has produced large explosive eruptions. Most active volcanoes in Mexico occur in the Trans-Mexican Volcanic Belt, which extends 900 kilometres (559 mi) from west to east across central-southern Mexico. A few other active volcanoes in northern Mexico are related to extensional tectonics of the Basin and Range Province, which split the Baja California peninsula from the mainland.^[12] Popocatépetl lies in the eastern half of the Trans-Mexican Volcanic Belt, which is the second highest peak in Mexico after the Pico de Orizaba. It is one of most active volcanoes in Mexico, having had more than 20 major eruptions since the arrival of the Spanish in 1519. The 1982 eruption of El Chichón killed about 2,000 people who lived near the volcano. It created a 1 kilometre (1 mi) wide caldera that filled with an acidic crater lake. Prior to 2000, this relatively unknown volcano was heavily forested and of no greater height than adjacent non-volcanic peaks.^[12]

...United States

 

 

Area of the Cascadia subduction zone, including the Cascade Volcanic Arc (red triangles)

 

In the western United States lies the Cascade Volcanic Arc. It includes nearly 20 major volcanoes, among a total of over 4,000 separate volcanic vents including numerous stratovolcanoes, shield volcanoes, lava domes, and cinder cones, along with a few isolated examples of rarer volcanic forms such as tuyas. Volcanism in the arc began about 37 million years ago, however, most of the present-day Cascade volcanoes are less than 2,000,000 years old, and the highest peaks are less than 100,000 years old. It formed by subduction of the Gorda and Juan de Fuca plates at the Cascadia subduction zone. This is a 680 mi (1,090 km) long fault, running 50 mi (80 km) off the west-coast of the Pacific Northwest from northern California to Vancouver Island, British Columbia. The plates move at a relative rate of over 0.4 inches (10 mm) per year at a somewhat oblique angle to the subduction zone.
Because of the very large fault area, the Cascadia subduction zone can produce very large earthquakes, magnitude 9.0 or greater, if rupture occurred over its whole area. When the "locked" zone stores energy for an earthquake, the "transition" zone, although somewhat plastic, can rupture. Thermal and deformation studies indicate that the locked zone is fully locked for 60 kilometers (about 40 miles) down-dip from the deformation front. Further down-dip, there is a transition from fully locked to aseismic sliding.

American Cascade Range volcano eruptions in the last 4000 years

 

Unlike most subduction zones worldwide, there is no oceanic trench present along the continental margin in Cascadia. Instead, terranes and the accretionary wedge have been uplifted to form a series of coast ranges and exotic mountains. A high rate of sedimentation from the outflow of the three major rivers (Fraser River, Columbia River, and Klamath River) which cross the Cascade Range contributes to further obscuring the presence of a trench. However, in common with most other subduction zones, the outer margin is slowly being compressed, similar to a giant spring. When the stored energy is suddenly released by slippage across the fault at irregular intervals, the Cascadia subduction zone can create very large earthquakes such as the magnitude 9 Cascadia earthquake of 1700. Geological evidence indicates that great earthquakes may have occurred at least seven times in the last 3,500 years, suggesting a return time of 400 to 600 years. There is also evidence of accompanying tsunamis with every earthquake, as the prime reason they know of these earthquakes is through "scars" the tsunami left on the coast, and through Japanese records (tsunami waves can travel across the Pacific).
The 1980 eruption of Mount St. Helens was the most significant to occur in the contiguous 48 U.S. states in recorded history (VEI = 5, 0.3 cu mi, 1.2 km³ of material erupted), exceeding the destructive power and volume of material released by the 1915 eruption of California's Lassen Peak. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the mountain that created a huge bulge and a fracture system on Mount St. Helens' north slope. An earthquake at 8:32 a.m. on May 18, 1980, caused the entire weakened north face to slide away, suddenly exposing the partly molten, gas- and steam-rich rock in the volcano to lower pressure. The rock responded by exploding into a very hot mix of pulverized lava and older rock that sped toward Spirit Lake so fast that it quickly passed the avalanching north face.
Alaska is known for its seismic and volcanic activity, holding the record for the second largest earthquake in the world the Good Friday Earthquake, and having more than 50 volcanoes which have erupted since about 1760.^[13] Volcanoes can be found not only in the mainland but also in the Aleutian Islands.
The most recent activity in the American portion of the Ring of Fire occurred in early 2009 when Mount Redoubt in Alaska became active and finally erupted late in the evening of March 22. The eruption ended in May 2009.

There's a lot more information on Wikipedia if you're interested.  I'm just glad I'm here...

...love that granite....

Beachfront property?...

 Teddee