RSS

Gempa Manokwari dan Pembentukan Sesar Sorong

07 Jan
Kondisi Tektonik Papua

Kondisi Tektonik Papua

 Gambar di samping menunjukkan kondisi tektonik Papua. Sesar Sorong di Papua ini yang menyebabkan gempa pada tanggal 4 Januari 2009 yang lalu. Data BMG menyebutkan kekuatan gempa 7.9 SR (kedalaman 48 km) dan 7.6 SR (kedalaman 10 km). Kedua gempa ini berselang tidak lebih dari 3 jam.

Sedangkan data USGS menyebutkan 7.4 SR dengan kedalaman 38 km.

Berikut ini summary dari USGS

The magnitude 7.4 Papua, Indonesia earthquake of January 3, 2009, 22:33 UTC, occurred as a result of thrust faulting on a plate-boundary along the northwest coast of the island of New Guinea. Eastern Indonesia is characterized by complex tectonics in which motions of numerous small plates are accommodating large-scale convergence between the Australia, Pacific, and Eurasia plates. In broad-scale plate-tectonic models that do not subdivide continent sized plates into smaller plates, the location of today’s earthquake would be on the boundary of the Pacific and Australia plates. The Pacific plate (located north and northeast of the epicenter) is moving southwest with respect to the Australia plate (located south of the epicenter) with a velocity of about 112 mm/year at the epicenter of the earthquake, and the focal-mechanism of today’s earthquake is broadly consistent with Pacific plate lithosphere being subducted beneath Australia plate lithosphere. The subduction zone along the northwest coast of New Guinea is characterized by an offshore oceanic trench, the New Guinea trench, but teleseismically recorded earthquake hypocenters do not show a well-developed inclined seismic zone (a Wadati-Benioff zone) dipping south-southwest from the trench.

Lokasi Gempa menurut USGS

The earthquake of January 3, 2009, 22:33 UTC, occurred about 400 km west of the magnitude 8.2 earthquake of February 17, 1996. The 1996 earthquake produced a tsunami that was destructive on the island of Biak. At least 108 people were killed by the 1996 earthquake and associated tsunami.

The magnitude 7.4 earthquake of January 3, 2009, 22:33 UTC, had the same focal-mechanism as the magnitude 7.6 shock of the same date, 19:43 UTC, and was located about 70 km east of the earlier shock. It was almost certainly triggered by the earlier earthquake. Seismologists sometimes refer to a pair of similarly sized shocks that occur at nearly the same time and location as an earthquake “doublet.”

Berikut ini animasi pembentukan Sesar Sorong. Di bagian kanan atas terdapat angka yang menunjukkan umur dalam satuan ‘juta tahun yang lalu’. Dari animasi ini kita mengetahui bahwa daerah Papua memang memiliki kondisi tektonik yang rumit dengan sesar-sesar yang sangat aktif. 

Sumber animasi dari blog Dongeng Geologi

Animasi tektonik ini dibuat Oleh Robert Hall tahun 2001. Professor Robert Hall adalah Director of the SE Asia Research Group, Degree Programme Co-ordinator MSci Environmental Geology di Royal Halloway, University of London, Inggris.

 
4 Komentar

Ditulis oleh pada Januari 7, 2009 in Geo-dinamik, Kebencanaan, Kegempaan

 

Tag: , , , ,

4 responses to “Gempa Manokwari dan Pembentukan Sesar Sorong

  1. Lala

    Januari 7, 2009 at 5:41 pm

    Indonesia termasuk dalam jalur rentan gempa ya

    🙂 Iya, betul sekali. umumnya gempa berasosiasi dengan jalur penunjaman antara lempeng tektonik. Indonesia bagian timur, kondisi tektoniknya lebih rumit lagi, karena yang tumbukannya antara tiga lempeng tektonik sekaligus.
    Jadi seperti kata Pak Awang Satyana, “Indonesia is sleeping with earthquake!”

     
  2. our

    Januari 14, 2009 at 1:20 pm

    duh…gempa lagi..bencana ga selesai2 karna bumi terus berenkarnasih…sedihnya liat sodaraku jadi korban. Lebih sedih lagi karna kita lebih tertarik sama bencana di Palestina di banding bencana di negri sendiri, balence dong… -_-

     
  3. canti

    November 11, 2009 at 10:00 am

    gempa lagi-gempa lagi …………alam mau menunjukan betapa dirinya disiksa oleh manusia

     
  4. ainta

    November 11, 2009 at 10:04 am

    apakah setiap pulau ada jalur gempa ya…………..?

     

Tinggalkan Balasan

Isikan data di bawah atau klik salah satu ikon untuk log in:

Logo WordPress.com

You are commenting using your WordPress.com account. Logout / Ubah )

Gambar Twitter

You are commenting using your Twitter account. Logout / Ubah )

Foto Facebook

You are commenting using your Facebook account. Logout / Ubah )

Foto Google+

You are commenting using your Google+ account. Logout / Ubah )

Connecting to %s

 
%d blogger menyukai ini: