Fire Earth

Mass die-offs from human impact and planetary response to the assault could occur by early 2016

Significant Earthquakes Strike Oklahoma

Posted by feww on December 29, 2013

9 Percent of the day’s global seismicity occurred in Oklahoma, 17 percent in Lower 48!!

M4.1 earthquakes strikes near Langston, Oklahoma

The quake was centered at 35.896°N, 97.306°W and struck at a depth of about 5.0km (3.1mi). 

Earthquake Details

  • Magnitude: 4.1Mw
  • Event Time: 2013-12-29 08:14:36 UTC
  • Location: 35.896°N 97.306°W depth=5.0km (3.1mi)
  • Nearby Cities:
    • 7km (4mi) SW of Langston, Oklahoma
    • 10km (6mi) E of Guthrie, Oklahoma
    • 31km (19mi) NNE of Edmond, Oklahoma
    • 33km (21mi) SW of Stillwater, Oklahoma
    • 51km (32mi) NNE of Oklahoma City, Oklahoma

Olahoma eq locmap
Oklahoma Earthquakes Location Map.

The event followed two smaller earthquakes measuring

  • M3.4  (Location 36.870°N 97.622°W depth=4.3km; 155km N of Oklahoma City) and
  • M3.1 (36.141°N 97.329°W depth=5.0km; 76km NNE of Oklahoma City).

30 day EQs in Oklahoma and Texas
30 Days, Magnitude 2.5+ Earthquakes in Texas, Oklahoma and Kansas. 40 Earthquakes in the map area. Global map includes 1012 earthquakes – Updated: 2013-12-29 10:06:05UTC. Source: USGS/EHP

About 17  percent of the global seismicity in the past 30 days, in terms of number of events measuring M2.5+, occurred in or near contiguous United States.

Oklahoma Earthquakes in November

At least 41 earthquakes measuring 2.5Mw or greater struck the state of Oklahoma in November 2013, according to data provided by USGS/EHP.

The largest shock in the cluster (No. 11 on the table below) measured 3.8Mw, striking at a depth of 5.9km on November 11, 2013 some 5km WNW of Jones, Oklahoma.

ok quakes nov2013-s
List of Oklahoma Earthquakes measuring 2.5Mw or greater, November 2013.

Tectonic Summary [USGS/EHP]

Induced Seismicity. As is the case elsewhere in the world, there is evidence that some central and eastern North America earthquakes have been triggered or caused by human activities that have altered the stress conditions in earth’s crust sufficiently to induce faulting. Activities that have induced felt earthquakes in some geologic environments have included impoundment of water behind dams, injection of fluid into the earth’s crust, extraction of fluid or gas, and removal of rock in mining or quarrying operations. In much of eastern and central North America, the number of earthquakes suspected of having been induced is much smaller than the number of natural earthquakes, but in some regions, such as the south-central states of the U.S., a significant majority of recent earthquakes are thought by many seismologists to have been human-induced. Even within areas with many human-induced earthquakes, however, the activity that seems to induce seismicity at one location may be taking place at many other locations without inducing felt earthquakes. In addition, regions with frequent induced earthquakes may also be subject to damaging earthquakes that would have occurred independently of human activity. Making a strong scientific case for a causative link between a particular human activity and a particular sequence of earthquakes typically involves special studies devoted specifically to the question. Such investigations usually address the process by which the suspected triggering activity might have significantly altered stresses in the bedrock at the earthquake source, and they commonly address the ways in which the characteristics of the suspected human-triggered earthquakes differ from the characteristics of natural earthquakes in the region.

one-day quakes worldwide 28-29 december 13
Earthquake Location Map. 1 Day, Magnitude 2.5+ Earthquakes Worldwide. 34 earthquakes shown on the map, updated at 2013-12-29 09:49:36 UTC. Source: USGS/EHP

M5.8 Quake Strikes Off the Coast of Turkey

  • Event Time:2013-12-28 15:21:05 UTC
  • Location: 35.980°N 31.340°E depth=51.1km (31.7mi)
  • Nearby Cities
    • 80km (50mi) SSW of Avsallar, Turkey
    • 204km (127mi) WNW of Nicosia, Cyprus

Tectonic Summary: Seismotectonics of the Mediterranean Region and Vicinity

The Mediterranean region is seismically active due to the northward convergence (4-10 mm/yr) of the African plate with respect to the Eurasian plate along a complex plate boundary. This convergence began approximately 50 Ma and was associated with the closure of the Tethys Sea. The modern day remnant of the Tethys Sea is the Mediterranean Sea. The highest rates of seismicity in the Mediterranean region are found along the Hellenic subduction zone of southern Greece, along the North Anatolian Fault Zone of western Turkey and the Calabrian subduction zone of southern Italy. Local high rates of convergence at the Hellenic subduction zone (35mm/yr) are associated with back-arc spreading throughout Greece and western Turkey above the subducting Mediterranean oceanic crust.

 
The region of the Marmara Sea is a transition zone between this extensional regime, to the west, and the strike-slip regime of the North Anatolian Fault Zone, to the east. The North Anatolian Fault accommodates much of the right-lateral horizontal motion (23-24 mm/yr) between the Anatolian micro-plate and Eurasian plate as the Anatolian micro-plate is being pushed westward to further accommodate closure of the Mediterranean basin caused by the collision of the African and Arabian plates in southeastern Turkey. Subduction of the Mediterranean Sea floor beneath the Tyrrhenian Sea at the Calabrian subduction zone causes a significant zone of seismicity around Sicily and southern Italy. Active volcanoes are located above intermediate depth earthquakes in the Cyclades of the Aegean Sea and in southern Italy.

In the Mediterranean region there is a written record, several centuries long, documenting pre-instrumental seismicity (pre-20th century). Earthquakes have historically caused widespread damage across central and southern Greece, Cyprus, Sicily, Crete, the Nile Delta, Northern Libya, the Atlas Mountains of North Africa and the Iberian Peninsula. The 1903 M8.2 Kythera earthquake and the 1926 M7.8 Rhodes earthquakes are the largest instrumentally recorded Mediterranean earthquakes, both of which are associated with subduction zone tectonics. Between 1939 and 1999 a series of devastating M7+ strike-slip earthquakes propagated westward along the North Anatolian Fault Zone, beginning with the 1939 M7.8 Erzincan earthquake on the eastern end of the North Anatolian Fault system. The 1999 M7.6 Izmit earthquake, located on the westward end of the fault, struck one of Turkey’s most densely populated and industrialized urban areas killing, more than 17,000 people. Although seismicity rates are comparatively low along the northern margin of the African continent, large destructive earthquakes have been recorded and reported from Morocco in the western Mediterranean, to the Dead Sea in the eastern Mediterranean. The 1980 M7.3 El Asnam earthquake was one of Africa’s largest and most destructive earthquakes within the 20th century.

Large earthquakes throughout the Mediterranean region have also been known to produce significant and damaging tsunamis. One of the more prominent historical earthquakes within the region is the Lisbon earthquake of November 1, 1755, whose magnitude has been estimated from non-instrumental data to be about 8.0. The 1755 Lisbon earthquake is thought to have occurred within or near the Azores-Gibraltar transform fault, which defines the boundary between the African and Eurasian plates off the west coast of Morocco and Portugal. The earthquake is notable for both a large death toll of approximately 60,000 people and for generating a tsunami that swept up the Portuguese coast inundating coastal villages and Lisbon. An earthquake of approximately M8.0 near Sicily in 1693 generated a large tsunami wave that destroyed numerous towns along Sicily’s east coast. The M7.2 December 28, 1908 Messina earthquake is the deadliest documented European earthquake. The combination of severe ground shaking and a local tsunami caused an estimated 60,000 to 120,000 fatalities.  [Source:USGS National Earthquake Information Center.]

Related Links

About these ads

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

 
Follow

Get every new post delivered to your Inbox.

Join 393 other followers