Saturday, 9 September 2017

Magnitude 8.1 Earthquake off the coast of Oaxaca State, Mexico, kills sixty four.

The United States Geological Survey recorded a Magnitude 8.1 Earthquake at a depth of 69.7 km off the coast of southwest Oaxaca State in southern Mexico slightly before 11.50 pm local time on Thursday 7 September 2017 (slightly before 4.50 am on Friday 8 September GMT).The event has caused widespread destruction, particularly in Oaxaca State, with the worst damage recorded in the city of Juchitan, were 36 people have been reported dead and about a third of the city's buildings have been destroyed. Nine people have died elsewhere in Oaxaca State, and a further twenty five people in neighbouring states with Chiapas State being particularly badly hit. The event triggered a small tsunami, with waves a meter high recorded on the coast of Mexico, and smaller waves being observed as far away as Fiji.

A damaged building in the town of Matias Romero in Oaxaca State, following the 7 September 2017 Earthquake. AP.

Southern Mexico is located on the southernmost part of the North American Plate. To the south, along the Middle American Trench, which lies off the southern coast off Mexico, the Cocos Plate is being subducted under the North American Plate, passing under southern Mexico as it sinks into the Earth. This is not a smooth process, and the plates frequently stick together then break apart as the pressure builds up, causing Earthquakes on the process.

 The approximate location of the 7 September 2017 Mexico Earthquake. USGS.

The Cocos Plate is thought to have formed about 23 million years ago, when the Farallon Plate, an ancient tectonic plate underlying the East Pacific, split in two, forming the Cocos Plate to the north and the Nazca Plate to the south. Then, roughly 10 million years ago, the northwesternmost part of the Cocos Plate split of to form the Rivera Plate, south of Beja California.  

The position of the Cocos, Nazca and Rivera Plates. MCEER/University at Buffalo.

In a paper published in the Journal of Geophysical Research, in 2012, a team led by Igor Stubailo of the Department of Earth and Space Sciences at the University of California Los Angeles, published a model of the subduction zone beneath Mexico using data from seismic monitoring stations belonging to the Mesoamerican Seismic Experiment, the Network of Autonomously Recording Seismographs, the USArray, Mapping the Rivera Subduction Zone and the Mexican Servicio Sismologico Nacional.

The seismic monitoring stations were able to monitor not just Earthquakes in Mexico, but also Earthquakes in other parts of the world, monitoring the rate at which compression waves from these quakes moved through the rocks beneath Mexico, and how the structure of the rocks altered the movement of these waves.

Based upon the results from these monitoring stations, Stubailo et al. came to the conclusion that the Cocos Plate was split into two beneath Mexico, and that the two plates are subducting at different angles, one steep and one shallow. Since the rate at which a plate melts reflects its depth within the Earth, the steeper angled plate melts much closer to the subduction zone than the shallower angled plate, splitting the Trans-Mexican Volcanic Belt into sections above the different segments of the Cocos Plate, and causing it to apparently curve away from the subduction zone.

 Top the new model of the Cocos Plate beneath Mexico, split into two sections (A & B) subducting at differing angles. (C) Represents the Rivera Plate, subducting at a steeper angle than either section of the Cocos Plate. The Split between the two has been named the Orozco Fracture Zone (OFZ) which is shown extended across the Cocos Plate; in theory this might in future split the Cocos Plate into two segments (though not on any human timescale). Bottom Left, the position of the segments on a map of Mexico. Darker area is the Trans-Mexican Volcanic Belt, orange circles are volcanoes, brown triangles are seismic monitoring stations, yellow stars are major cities. Bottom Right, an alternative model showing the subducting plate twisted but not split. This did not fit the data. Stubailo et al. (2012).
 
Earthquakes along subductive margins are particularly prone to causing tsunamis, since these often occur when the overlying plate has stuck to the underlying plate, being pulled out of shape by its movement.. Eventually the pressure builds up too far and the overlying plate snaps back, causing an Earthquake and a tsunami.

 Simplified graphic showing tsunami generation along a convergent margin.NASA/JPL/CalTech.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.
 
See also...
 
http://sciencythoughts.blogspot.co.uk/2017/08/explosion-kills-one-and-injures-five-as.htmlhttp://sciencythoughts.blogspot.co.uk/2017/07/sinkhole-swallows-bus-in-veracruz-mexico.html
http://sciencythoughts.blogspot.co.uk/2017/03/magnitude-57-earthquake-beneath-gulf-of.htmlhttp://sciencythoughts.blogspot.co.uk/2017/02/eruption-and-pyroclastic-flow-on-volcan.html
http://sciencythoughts.blogspot.co.uk/2017/01/eruption-on-volcan-de-colima.htmlhttp://sciencythoughts.blogspot.co.uk/2016/12/further-eruptions-on-volcan-de-colima.html
Follow Sciency Thoughts on Facebook.

4 comments:

  1. kami sekeluarga tak lupa mengucapkan puji syukur kepada ALLAH S,W,T
    dan terima kasih banyak kepada AKI atas bantuan nomor togel.nya yang AKI
    berikan MAGNUM 4D yaitu ((( 5 5 4 8 ))) alhamdulillah ternyata itu benar2 tembus AKI.
    dan alhamdulillah sekarang saya bisa melunasi semua utan2 saya yang
    ada sama tetangga.dan juga BANK BRI dan bukan hanya itu AKI. insya
    allah saya akan coba untuk membuka usaha sendiri demi mencukupi
    kebutuhan keluarga saya sehari-hari itu semua berkat bantuan AKI..
    sekali lagi makasih banyak ya AKI bagi saudara yang suka main togel
    yang ingin merubah nasib seperti saya silahkan hubungi AKI SOLEH,,DI NO Cll (((082-313-336-747)))
    insya allah anda bisa seperti Saya menang togel 185
    juta, wassalam.

    dijamin 100% jebol saya sudah buktikan...sendiri....

    Apakah anda termasuk dalam kategori di bawah ini !!!!

    1"Dikejar-kejar hutang

    2"Selaluh kalah dalam bermain togel

    3"Barang berharga anda udah habis terjual Buat judi togel

    4"Anda udah kemana-mana tapi tidak menghasilkan solusi yg tepat

    5"Udah banyak Dukun togel yang kamu tempati minta angka jitunya
    tapi tidak ada satupun yang berhasil..

    Solusi yang tepat jangan anda putus asah....AKI SOLEH akan membantu
    anda semua dengan Angka ritwal/GHOIB:
    butuh angka togel 2D 3D 4D SGP / HKG / MALAYSIA / TOTO MAGNUM / dijamin
    100% jebol
    Apabila ada waktu
    silahkan Hub: AKI SOLEH DI NO: Cll (((082-313-336-747)))

    KLIK DISINI ((((( BOCORAN TOGEL HARI INI ))))


    angka GHOIB: singapur 2D/3D/4D/

    angka GHOIB: hongkong 2D/3D/4D/

    angka GHOIB; malaysia

    angka GHOIB; toto magnum 4D/5D/6D/

    angka GHOIB; laos

    ReplyDelete
  2. kami sekeluarga tak lupa mengucapkan puji syukur kepada ALLAH S,W,T
    dan terima kasih banyak kepada AKI atas bantuan nomor togel.nya yang AKI
    berikan MAGNUM 4D yaitu ((( 5 5 4 8 ))) alhamdulillah ternyata itu benar2 tembus AKI.
    dan alhamdulillah sekarang saya bisa melunasi semua utan2 saya yang
    ada sama tetangga.dan juga BANK BRI dan bukan hanya itu AKI. insya
    allah saya akan coba untuk membuka usaha sendiri demi mencukupi
    kebutuhan keluarga saya sehari-hari itu semua berkat bantuan AKI..
    sekali lagi makasih banyak ya AKI bagi saudara yang suka main togel
    yang ingin merubah nasib seperti saya silahkan hubungi AKI SOLEH,,DI NO Cll (((082-313-336-747)))
    insya allah anda bisa seperti Saya menang togel 185
    juta, wassalam.

    dijamin 100% jebol saya sudah buktikan...sendiri....

    Apakah anda termasuk dalam kategori di bawah ini !!!!

    1"Dikejar-kejar hutang

    2"Selaluh kalah dalam bermain togel

    3"Barang berharga anda udah habis terjual Buat judi togel

    4"Anda udah kemana-mana tapi tidak menghasilkan solusi yg tepat

    5"Udah banyak Dukun togel yang kamu tempati minta angka jitunya
    tapi tidak ada satupun yang berhasil..

    Solusi yang tepat jangan anda putus asah....AKI SOLEH akan membantu
    anda semua dengan Angka ritwal/GHOIB:
    butuh angka togel 2D 3D 4D SGP / HKG / MALAYSIA / TOTO MAGNUM / dijamin
    100% jebol
    Apabila ada waktu
    silahkan Hub: AKI SOLEH DI NO: Cll (((082-313-336-747)))

    KLIK DISINI ((((( BOCORAN TOGEL HARI INI ))))


    angka GHOIB: singapur 2D/3D/4D/

    angka GHOIB: hongkong 2D/3D/4D/

    angka GHOIB; malaysia



    angka GHOIB; toto magnum 4D/5D/6D/

    angka GHOIB; laos

    ReplyDelete
  3. Thank you for this valuable information, I hope it is okay that I bookmarked your website for further references.

    Flat earth

    ReplyDelete
  4. Halo,
    Ini adalah untuk memaklumkan kepada orang ramai bahawa Puan Henrietta Fernando, pemberi pinjaman pinjaman swasta telah membuka peluang kewangan kepada sesiapa yang memerlukan sebarang bantuan kewangan. Kami memberi pinjaman pada kadar faedah 2% untuk individu, syarikat dan syarikat di bawah terma dan syarat yang jelas dan difahami. Hubungi kami hari ini melalui e-mel untuk memohon dan mendapatkan pinjaman segera: (henriettafernandoloanfirm@gmail.com)

    ReplyDelete