Not Another, Gosh: Vanuatu hit by large quake

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Discussion Overview

The discussion centers around a recent large earthquake near Vanuatu, including its characteristics, potential tsunami risks, and the frequency of such seismic events. Participants explore the implications of detection technology on perceived earthquake frequency and the geological context of the region.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that a large earthquake has struck near Vanuatu, with tsunami waves possible within 300km of the epicenter.
  • Another expresses concern that large magnitude earthquakes seem to be becoming more common.
  • Some participants suggest that improved detection technology and population growth may contribute to the perception of increased earthquake frequency, while others argue that statistical data does not support this view.
  • A participant provides specific details about the earthquake's magnitude, depth, and location, referencing USGS data.
  • There is a discussion about whether the recent seismic activity is related to a fault line, with one participant explaining the geological context of the region as a subduction zone.
  • Additional seismic events in the region are mentioned, indicating ongoing geological activity.

Areas of Agreement / Disagreement

Participants express differing views on the frequency of large magnitude earthquakes, with some asserting that the yearly averages have not changed significantly, while others feel that such events are becoming more common. The discussion remains unresolved regarding the implications of detection technology on perceived earthquake frequency.

Contextual Notes

Participants reference statistical data and geological explanations, but there are unresolved assumptions about the interpretation of earthquake frequency and the relationship to detection technology.

StevieTNZ
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Ugh . . . large magnitude earthquakes are becoming more and more common.
 
As our detection technology gets better and as our population (and therefore technologists) become more numerous, it does seem as if things once uncommon are now appearing more frequently. However, a quick look at the stats usually dispels this feeling. And, of course, we do have flurries of activity at almost every level.
 
True, but you don't need detection technology to notice a 7.0 magnitude earthquake :) Just sayin'.

I get what you're saying, though.
 
ProfuselyQuarky said:
Ugh . . . large magnitude earthquakes are becoming more and more common.

no they are not ... the yearly averages haven't changed in the last 100 or so years

ON avg. there are around 18 x M7.0 - 7.9 events each year, that equals 1 event in that range every 21 days
for M 8.0 and greater 1 per year. Some years see 2 x M8+ events other years there are noneDave
 
StevieTNZ said:
http://www.stuff.co.nz/world/south-pacific/79430986/vanuatu-hit-by-large-quake

Happened ~30 mins ago, so information still coming in.

Hi Stevie

Yup, the Vanuatu area is keeping its name as a very seismically active region
This latest M 7.0 was onshore in the centre of the Island Archipelago, and this meant that a tsunami was unlikely

The distance from recent large events to the north of this one make it a new separate event rather than an aftershock.

2016-04 Vanuatu Event 2.JPG
cheers
Dave
 
Connecting the dots, is this a fault line?
 
MRBlizzard said:
Connecting the dots, is this a fault line?

Hi there

not in this case, the events ... main shock and aftershock events are actually showing the direction that the fault line dips at

The main fault line, that is, the plate boundary, is shown by the red line running roughly north - south in the above pic
This region is a subduction zone with seafloor west ( left) of that red line, diving down under the seafloor/land to the east (right) of the line

so in cross-section we see something like this ...
( a very quick and rough drawing) not to scale but will give you the idea :smile:
subduction.GIF


The black dots being the quakes
cheers
Dave
 
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