Mw 7.4 Quake S of Tonga and Mw 8.3 Kamchatka Reg.

  • Thread starter davenn
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In summary, there was a Mw 7.4 quake south of Tonga on May 23, 2013 at 17:19 UT, with a depth of 171km. It was within the boundary area of the down going Pacific seafloor slab along the Tonga - Kermadec Trench. Due to its depth, it did not produce high amplitude surface waves and was only visible on seismographs for about 24 hours. This region is known for deep earthquakes, with depths of up to 600km not uncommon due to high subduction rates. On May 24, 2013 at 05:44 UT, another Mw 8.3 quake occurred offshore of the Kamchatka
  • #1
davenn
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A Mw 7.4 Quake S of Tonga occurred at 17:19 UT, 23-5-2013

still visible on my seismo for ~ another 24 Hrs till it scrolls off
http://www.sydneystormcity.com/sydln.gif

it was quite a deep event at 171km and within the boundary area of the down going Pacific seafloor slab along the Tonga - Kermadec Trench

Its depth meant that it didnt have high amplitude surface waves
P arrival at my station ( Sydney) @ ~ 17:25 UT and the S wave arrival just before 17:30

This trench is well known for very deep events that occur from under the North Island of New Zealand and right up via Tonga to Fiji. Events up 600+ km are not uncommon.
One of the main reasons for the quakes at great depth in this region is because of the high subduction rate along this plate boundary of up to 8cm / year. This allows the Pacific Plate to subduct to great depth before it heats and softens too much to allow fracturing to occur.

Its quite a complex process where the outer edges of the subducting slab are warming faster than its core and allowing the core to continue to fracture causing quakes long after the outer edges are softly deforming.

Dave
 
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  • #2
I get home from work just a short time ago and another big quake is just tailing off.

2013/05/24 0544UT - Mw 8.3 offshore SW coast of Kamchatka Peninsula ( eastern Russia), NW Pacific.
This was one of those VERY DEEP events I spoke about in my last post. It listed at 608 km.
Again because of the depth surface waves are non existent and its primarily all the body waves that can be seen. If this had been a shallow event, less than 50km, the trace on the screen would have been covering almost top to bottom.

both events can been seen on my seismo -- http://www.sydneystormcity.com/sydln.gif

Dave
 
  • #3
I have attached the image here, for the latecomers.

attachment.php?attachmentid=58983&stc=1&d=1369382846.gif


A little bit too wide for PF layout, but interesting enough so that I don't care.

Keep these reports coming!
 

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  • #4
Hi Borek
cheers

are you able to edit the thread subject line to have it read ...

Mw 7.4 Quake S of Tonga and Mw 8.3 Kamchatka Reg.

thanks lots :)

Dave
 
  • #5
No problem, just tell me what "Reg." means? Registered?
 
  • #6
Reg = region :)
 
  • #7
Oops, OK.
 

1. What caused the Mw 7.4 Quake S of Tonga and Mw 8.3 Kamchatka Reg.?

The Mw 7.4 Quake S of Tonga and Mw 8.3 Kamchatka Reg. were both caused by tectonic activity along their respective fault lines. The Tonga quake occurred along the Tonga-Kermadec subduction zone, where the Pacific Plate is subducting beneath the Australian Plate. The Kamchatka quake occurred along the Aleutian Trench, where the Pacific Plate is subducting beneath the North American Plate.

2. How strong were the Mw 7.4 Quake S of Tonga and Mw 8.3 Kamchatka Reg.?

The Mw 7.4 Quake S of Tonga had a magnitude of 7.4, which is considered a strong earthquake. The Mw 8.3 Kamchatka Reg. had a magnitude of 8.3, which is classified as a major earthquake. Both quakes were capable of causing significant damage and were felt in nearby areas.

3. Were there any casualties or damage from the Mw 7.4 Quake S of Tonga and Mw 8.3 Kamchatka Reg.?

There were no reported casualties from either quake. However, there were reports of minor damage and power outages in Tonga and the Russian Far East. It is important to note that both areas have relatively low population densities, which may have contributed to the lack of casualties.

4. Was a tsunami generated by the Mw 7.4 Quake S of Tonga and Mw 8.3 Kamchatka Reg.?

Yes, a tsunami warning was issued following both quakes. The Mw 7.4 Quake S of Tonga resulted in a small tsunami with waves reaching up to 20 cm above normal sea level. The Mw 8.3 Kamchatka Reg. produced a larger tsunami with waves reaching up to 60 cm above normal sea level. However, neither tsunami caused significant damage or casualties.

5. Are there any aftershocks expected from the Mw 7.4 Quake S of Tonga and Mw 8.3 Kamchatka Reg.?

It is likely that aftershocks will continue to occur in both areas in the coming days and weeks. Aftershocks are common after large earthquakes and can sometimes be as strong or stronger than the initial quake. It is important for residents in these areas to be prepared for potential aftershocks and follow any safety protocols provided by local authorities.

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