Major quake in eastern New Britain PNG NOW

[davenn]

Eastern New Britain is being severely rattled over the last week
starting on the 30th April with a M 6.7 and shortly after a M 6.8 followed by numerous aftershocks over the last 5 days.

A M 7.4 has now hit the same area
http://www.sydneystormcity.com/seismograms.htm

as can be seen, the seismo trace is hitting the stops, top to bottom of the displaycheers
Dave

 

[Greg Bernhardt]

Saw the news story earlier. btw, the US state Michigan had a M4 yesterday which is pretty rare for the area I think.

 

[davenn]

Hi Greg, yes I saw that, a M 4.2 ... one of that size would definitely be pretty rare in that region

There were supposed reports of it being felt in Milwaukee, WI ... seemed a bit doubtful considering the distance
But weird things happen, maybe those that felt it were in high rise buildings ?

Dave

 

[Greg Bernhardt]

But weird things happen, maybe those that felt it were in high rise buildings ?

Could be, I am downtown and didn't notice anything

 

[davenn]

OK just been putting together a graphic for this latest sequence and the last major event a month ago

data courtesy of USGS

cheers
Dave

 

[StevieTNZ]

NZ had an earthquake down South yesterday -- http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11443030

 

[davenn]

hi Stevie, yes a M 5.8

you can still see that on my online seismogram ... link in the first post

follow the time line along from the UTC 0200 and a few minutes after 0230 (~ 0234) the P wave starts

My Mom and Dad live a little inland from Dunedin, They felt it quite wellDave

 

[Astronuc]

USGS ranks it at M7.5 - 130km SSW of Kokopo, Papua New Guinea
http://earthquake.usgs.gov/earthquakes/eventpage/us20002bnf#general_summary
2015-05-05 01:44:05 (UTC)

Looks like they have somewhat of a swarm going on:

M5.2 - 124km SSW of Kokopo, Papua New Guinea 2015-05-05 02:40:23 (UTC)
M5.6 - 103km S of Kokopo, Papua New Guinea 2015-05-05 01:58:20 (UTC)
M5.9 - 109km SSW of Kokopo, Papua New Guinea 2015-05-05 01:54:05 (UTC)

Fortunately, they are decreasing in magnitude.

There have been 22 M7.5+ earthquakes recorded in the New Guinea region since 1900. The dominant earthquake mechanisms are thrust and strike slip, associated with the arc-continent collision and the relative motions between numerous local microplates. The largest earthquake in the region was a M8.2 shallow thrust fault event in the northern Papua province of Indonesia that killed 166 people in 1996.

The western portion of the northern Australia plate boundary extends approximately 4800 km from New Guinea to Sumatra and primarily separates Australia from the Eurasia plate, including the Sunda block. This portion is dominantly convergent and includes subduction at the Sunda (Java) trench, and a young arc-continent collision.

 

[davenn]

USGS ranks it at M7.5 - 130km SSW of Kokopo, Papua New Guinea

ohhhh its gone back up

it started as a 7.5 went down to a 7.4 and now back up again

Looks like they have somewhat of a swarm going on:

M5.2 - 124km SSW of Kokopo, Papua New Guinea 2015-05-05 02:40:23 (UTC)
M5.6 - 103km S of Kokopo, Papua New Guinea 2015-05-05 01:58:20 (UTC)
M5.9 - 109km SSW of Kokopo, Papua New Guinea 2015-05-05 01:54:05 (UTC)

they are just typical aftershocks of a large event
It isn't too often that 2 large events ... the 6.7 and 6.8, late last week would be followed by an even larger event

Dave

 

[Astronuc]

they are just typical aftershocks of a large event

Just the planet readjusting.

The area to watch for the next few days.

 

[davenn]

Just the planet readjusting.

uh huh

as you can see in that map graphic I did a few posts ago. There was the 7.5 a month ago, to the east, and its aftershock sequence was pretty much contained in the red box. I'm going to have to dig out my historical data and see what is happening seismic gap wise in the region

Dave

 

[Astronuc]

uh huh

as you can see in that map graphic I did a few posts ago. There was the 7.5 a month ago, to the east, and its aftershock sequence was pretty much contained in the red box. I'm going to have to dig out my historical data and see what is happening seismic gap wise in the region

Dave

The plate boundary between the Australia and Pacific plates in the Papua New Guinea region is very active seismically; 36 M 7+ events have occurred within 250 km of the May 5, 2015 earthquake over the past century. Few are known to have caused shaking-related fatalities because of the remoteness of the region, though a M 8.0 earthquake in November 2000 – one of three similarly sized events over a 2-day period – did cause several deaths. The largest nearby earthquake was an M 8.1 event, 150 km to the east-northeast of the May 5, 2015 earthquake, one of two M8+ earthquakes 140 km apart in July 1971. The May, 2015 earthquake is just 10 km to the east-northeast of the November 17, 2000 M 7.8 earthquake, also thrust-faulting event on the plate boundary interface.

The May 5 earthquake has also been preceded by a series of moderate-to-large earthquakes on this portion of the plate boundary over the past several weeks, beginning with a M 7.5 event on March 29, 2015, 110 km to the northeast of the May 5, 2015 earthquake. Between these two large events, 25 other earthquakes of M 5+ have occurred in the same area; including M 6.7 and M 6.8 events just to the northwest of the May 5 earthquake, on April 30 and May 1, respectively.

Ref: http://earthquake.usgs.gov/earthquakes/eventpage/us20002bnf#general_summary

One should be able to search the area between the dates (over the last century) and filter by magnitude.

On another site, I was following the seismic activity along the Sunda trench and intersections of the Australia, Indian, Eurasian and Pacific plants over the last 10 years. Unfortunately that site no longer exists.

I appreciate the 3D volumetric time dependent plots that some folks do that show the progression of swarms around a big event. I don't have the software to do that.

 

[davenn]

I was doing a search whilst you were typing
the whole region has been very active for M 7.0+ events

I appreciate the 3D volumetric time dependent plots that some folks do that show the progression of swarms around a big event. I don't have the software to do that.

Alan Jones ( maybe you know (of) him) does stuff along those lines ... has written some good software for display quakes around the world

Dave

 

[davenn]

I hate the way the forum software compresses the pix so much :(
turns them to crap to try and read