9/03/2014 — TWO 5.2M earthquakes in the Caribbean near Tsunami drill location from 2013

This is not something we see every day, nor every year for that matter.  Large earthquakes just South of Cuba.

TWO different 5.2M earthquakes struck South of the Cayman Islands in the Caribbean (on the Southern edge of the Gulf of Mexico).

Both events happened in the same 12 hour period, in the same location (separated by just a few miles)

caribbean earthquakes sept 3 2014


Ironically, last year (in 2013) NOAA partnered up with UNESCO to run a simulated 8.5M earthquake / tsunami drill in the same area.

A Gulf of Mexico / Caribbean Tsunami is something the government has been preparing for.

caribbean earthquakes sept 3 2014s

http://www.srh.noaa.gov/images/srh/ctwp/CaribeWave13.pdf

Download the .pdf from my site directly:

CaribeWave13


Here are the USGS statistics on both 5.2 magnitude events:

http://earthquake.usgs.gov/earthquakes/eventpage/usc000s9tf#summary

http://earthquake.usgs.gov/earthquakes/eventpage/usc000s98a#summary

 

M5.2 – 43km S of George Town, Cayman Islands 2014-09-03 23:34:14 UTC

Earthquake location 18.898°N, 81.317°W
18.899°N, 81.317°W
Depth: 10.0km (6.2mi)

Event Time

  1. 2014-09-03 23:34:14 UTC
  2. 2014-09-03 18:34:14 UTC-05:00 at epicenter
  3. 2014-09-03 18:34:14 UTC-05:00 system time

Location

18.898°N 81.317°W depth=10.0km (6.2mi)

Nearby Cities

  1. 43km (27mi) S of George Town, Cayman Islands
  2. 52km (32mi) SSE of West Bay, Cayman Islands
  3. 350km (217mi) SSW of Trinidad, Cuba
  4. 361km (224mi) W of Montego Bay, Jamaica
  5. 43km (27mi) S of George Town, Cayman Islands

 

Seismotectonics of the Caribbean Region and Vicinity

“Extensive diversity and complexity of tectonic regimes characterizes the perimeter of the Caribbean plate, involving no fewer than four major plates (North America, South America, Nazca, and Cocos). Inclined zones of deep earthquakes (Wadati-Benioff zones), ocean trenches, and arcs of volcanoes clearly indicate subduction of oceanic lithosphere along the Central American and Atlantic Ocean margins of the Caribbean plate, while crustal seismicity in Guatemala, northern Venezuela, and the Cayman Ridge and Cayman Trench indicate transform fault and pull-apart basin tectonics.

Along the northern margin of the Caribbean plate, the North America plate moves westwards with respect to the Caribbean plate at a velocity of approximately 20 mm/yr. Motion is accommodated along several major transform faults that extend eastward from Isla de Roatan to Haiti, including the Swan Island Fault and the Oriente Fault. These faults represent the southern and northern boundaries of the Cayman Trench. Further east, from the Dominican Republic to the Island of Barbuda, relative motion between the North America plate and the Caribbean plate becomes increasingly complex and is partially accommodated by nearly arc-parallel subduction of the North America plate beneath the Caribbean plate.

This results in the formation of the deep Puerto Rico Trench and a zone of intermediate focus earthquakes (70-300 km depth) within the subducted slab. Although the Puerto Rico subduction zone is thought to be capable of generating a megathrust earthquake, there have been no such events in the past century.

The last probable interplate (thrust fault) event here occurred on May 2, 1787 and was widely felt throughout the island with documented destruction across the entire northern coast, including Arecibo and San Juan. Since 1900, the two largest earthquakes to occur in this region were the August 4, 1946 M8.0 Samana earthquake in northeastern Hispaniola and the July 29, 1943 M7.6 Mona Passage earthquake, both of which were shallow thrust fault earthquakes.

A significant portion of the motion between the North America plate and the Caribbean plate in this region is accommodated by a series of left-lateral strike-slip faults that bisect the island of Hispaniola, notably the Septentrional Fault in the north and the Enriquillo-Plantain Garden Fault in the south. Activity adjacent to the Enriquillo-Plantain Garden Fault system is best documented by the devastating January 12, 2010 M7.0 Haiti strike-slip earthquake, its associated aftershocks and a comparable earthquake in 1770.

 

Moving east and south, the plate boundary curves around Puerto Rico and the northern Lesser Antilles where the plate motion vector of the Caribbean plate relative to the North and South America plates is less oblique, resulting in active island-arc tectonics.

Here, the North and South America plates subduct towards the west beneath the Caribbean plate along the Lesser Antilles Trench at rates of approximately 20 mm/yr. As a result of this subduction, there exists both intermediate focus earthquakes within the subducted plates and a chain of active volcanoes along the island arc. Although the Lesser Antilles is considered one of the most seismically active regions in the Caribbean, few of these events have been greater than M7.0 over the past century.

The island of Guadeloupe was the site of one of the largest megathrust earthquakes to occur in this region on February 8, 1843, with a suggested magnitude greater than 8.0. The largest recent intermediate-depth earthquake to occur along the Lesser Antilles arc was the November 29, 2007 M7.4 Martinique earthquake northwest of Fort-De-France.

The southern Caribbean plate boundary with the South America plate strikes east-west across Trinidad and western Venezuela at a relative rate of approximately 20 mm/yr. This boundary is characterized by major transform faults, including the Central Range Fault and the Boconó-San Sebastian-El Pilar Faults, and shallow seismicity.

Since 1900, the largest earthquakes to occur in this region were the October 29, 1900 M7.7 Caracas earthquake, and the July 29, 1967 M6.5 earthquake near this same region. Further to the west, a broad zone of compressive deformation trends southwestward across western Venezuela and central Columbia.

The plate boundary is not well defined across northwestern South America, but deformation transitions from being dominated by Caribbean/South America convergence in the east to Nazca/South America convergence in the west. The transition zone between subduction on the eastern and western margins of the Caribbean plate is characterized by diffuse seismicity involving low- to intermediate-magnitude (M<6.0) earthquakes of shallow to intermediate depth.

The plate boundary offshore of Colombia is also characterized by convergence, where the Nazca plate subducts beneath South America towards the east at a rate of approximately 65 mm/yr. The January 31, 1906 M8.5 earthquake occurred on the shallowly dipping megathrust interface of this plate boundary segment.

Along the western coast of Central America, the Cocos plate subducts towards the east beneath the Caribbean plate at the Middle America Trench. Convergence rates vary between 72-81 mm/yr, decreasing towards the north. This subduction results in relatively high rates of seismicity and a chain of numerous active volcanoes; intermediate-focus earthquakes occur within the subducted Cocos plate to depths of nearly 300 km. Since 1900, there have been many moderately sized intermediate-depth earthquakes in this region, including the September 7, 1915 M7.4 El Salvador and the October 5, 1950 M7.8 Costa Rica events.

The boundary between the Cocos and Nazca plates is characterized by a series of north-south trending transform faults and east-west trending spreading centers. The largest and most seismically active of these transform boundaries is the Panama Fracture Zone. The Panama Fracture Zone terminates in the south at the Galapagos rift zone and in the north at the Middle America trench, where it forms part of the Cocos-Nazca-Caribbean triple junction.

Earthquakes along the Panama Fracture Zone are generally shallow, low- to intermediate in magnitude (M<7.2) and are characteristically right-lateral strike-slip faulting earthquakes. Since 1900, the largest earthquake to occur along the Panama Fracture Zone was the July 26, 1962 M7.2 earthquake.

References for the Panama Fracture Zone:
Molnar, P., and Sykes, L. R., 1969, Tectonics of the Caribbean and Middle America Regions from Focal Mechanisms and Seismicity: Geological Society of America Bulletin, v. 80, p. 1639-1684.


9/03/2014 — Tropical Storm / Hurricane “Norbert” heading towards Southern California?

An end to the Southern California drought in sight?

norbert hurricaneaa
Above: Hurricane Norbert (Category 1) currently near the Southern tip of Baja Mexico, heading North towards Southern California , September 3 2014 2pm CDT

 

Hurricane Norbert (currently going into Category 1 hurricane status) is heading up the Western coast of Baja Mexico.

Professionals have the storm track staying a steady Northwest  along the coast of Mexico, topping out near a Category 2 storm, heading towards the Southwestern coast of the United States.

norbert hurricane 1
Above: September 3 2014 — Currently path of Hurricane Norbert shows a possible Southwest US interaction.
norbert hurricane
Above: The long term path is subject to change, however current path tracks show a steady push up the coast is expected.

 

If Norbert’s pattern holds, Southern California may be seeing the edge of a tropical storm.  This would be good news, if the rain which accompanies these tropical systems makes its way to SoCal !


Animated satellite images from NOAA can be seen here:

http://www.ssd.noaa.gov/PS/TROP/floaters/14E/14E_floater.html

http://tropic.ssec.wisc.edu/#

rbtop-animated norbert

rb-animated norbert

avn-animated norbert

rgb-animated norbert

swir-animated

latest72hrs

 


9/03/2014 — Rivers of lava flow at Bardarbunga Volcano, NEW explosions near Vatnajökull Glacier

Bardarbunga Volcano in Iceland has been erupting in an ‘on and off’ fashion over the past week.

The eruption, originally began as a subglacial event, coupled with dozens of 4.0M to upper 5.0M earthquakes which have moved with the underground flows of magma, has grown steadily in size.

Now, September 3, 2014.. the fissure which formed near the volcanoes caldera is producing flowing rivers of lava, spreading across the area.

Watch live here:

http://www.livefromiceland.is/webcams/bardarbunga-2/

Capturebardarbunga eruption sept 302014
Above: September 3 2014, Large volumes of lava now seen flowing from Bardarbunga Volcano in Iceland

 


Over the past week, first a fissure formed.. producing impressive daytime lava fountains..

Capture bardarbunga eruption
Above: Day 2 of the eruption, last 2 days of August 2014 a fissure formed near Bardarbunga’s caldera

Nighttime shots show the actual spreading of the fissure much better…

bardarbunga night time eruption sept 1 2014
Above: September 1 2014, A nighttime view of the new volcanic fissure at Bardarbunga Volcano

 


New reports yesterday of ‘explosions’ reported near Vatnajökull.

https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.ruv.is%2Ffrett%2Fsprengingar-i-eldgosinu-nordan-vatnajokuls&edit-text=&act=url

Terra_Iceland
Terra MODIS satellite image of the eruption north of Vatnajokull in Iceland peaking through the cloud cover. Seen on August 28, 2014. NASA

 

” RUV.is (Icelandic geologic agency) is reporting that three small explosions occurred in the area just north of Vatnajökull. The nature of the explosions are unknown at this point, but from the rough translation of the article in Icelandic, they sound an awful lot like a phreatic explosion — that is, explosions driven by steam. If magma is directly involved, they would then become phreatomagmatic. In both cases, it could be a case where intruding basalt is interacting with saturated sediment at the edges of the Vatnajökull. This area is likely going to be saturated with water from the seasonal melting of the ice sheet itself, so explosive interactions between this wet sediment and basalt might be expected. The resulting mix of sediment and lava is called a peperite. UPDATE: Although likely unrelated to today’s mysterious explosions, there could be a chance for phreatic explosions if/when the lava flow reaches Jokulsa River.

Not much can be seen in the webcams right now, beyond the abundant degassing from the active fissure zones in the Holahraun lava fields between Askja and Barðarbunga. The new fissure that opened Sunday has produced some impressive lava fountains, some reaching 200 meters (650 feet). The lava flow that is issuing from the new fissure is made of slabby pahoehoe, a flavor of basaltic lava that is transitional between pahoehoe and a’a. You can see some video of the lava flows here and a great flyover of the fissure and lava flow.

 

Earthquakes around Vatnajokull, with hot colors marking the most recent earthquakes. Date is in the top left corner. Illustration by Icelandic Meteorological Office.

Overall, the Icelandic Meteorological Office is reporting that seismicity is down over the last day, along with the rates of deformation seen in the area. It is interesting to note that this earthquake swarm has now progressed past Askja to the north (see right), with a bit of a “blank zone” under Askja. The eruption itself is also waning since the intense activity of Sunday and Monday. However, as we saw last week, if this fissure stops erupting, new ones may open — potentially related to the explosions reported today. The lava flow now covers about 4.2 square kilometers. The sulfur dioxide plume from the eruption is also prominent around Iceland and the North Atlantic, but it seems that much of the minor hazard due to the plume is localized to Iceland. You can read some more about the gas plume in this Daily Kos article, but be wary of the doom-and-gloom.

If you can’t make it to Iceland right now, be sure to check out the amazing collection of images from the eruption by Einar Guðmann.