Earthquake in South Pacific, NE of Australia

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Discussion Overview

The discussion revolves around a series of earthquakes in the South Pacific, particularly focusing on a significant earthquake near the Solomon Islands and its implications, including tsunami warnings and aftershocks. Participants share real-time data, observations, and reflections on media reporting of seismic events.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Meta-discussion

Main Points Raised

  • Some participants report on the issuance of tsunami warnings following a 7.8 magnitude earthquake near the Solomon Islands, with updates on the magnitude being revised.
  • One participant shares personal observations of seismic activity and discusses the arrival times of seismic waves from different earthquakes, suggesting calculations that align with standard models.
  • There is a mention of multiple earthquakes occurring within a short time frame, including a 6.0 magnitude quake in China, prompting questions about media reporting practices over time.
  • Participants discuss the perception of increased earthquake reporting in modern media compared to the past, noting that many significant events may go unreported due to their remote locations.
  • One participant provides statistics on the average number of earthquakes of various magnitudes occurring annually, suggesting that these figures have remained consistent over the last 150 years.
  • Updates on aftershocks following the main earthquake are shared, including a revision of a subsequent quake's magnitude.

Areas of Agreement / Disagreement

Participants express varying views on media reporting practices and the perception of earthquake frequency, with some suggesting that media coverage has increased while others argue that the actual occurrence rates have not changed significantly. The discussion remains unresolved regarding the implications of these observations.

Contextual Notes

Participants note the dependence on real-time data and the potential for revisions in earthquake magnitudes, as well as the limitations of media coverage in reporting seismic events.

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yeah a massive 7.8
68km WSW of Kirakira, Solomon Islands
2016-12-08 17:38:46 (UTC)
41.0 km

my seismo has only a short time ago stopped hitting the stops ... I was still sleeping when the event occurred and the seismic waves arrived at my location
so I couldn't do a screen save before it started overwriting itself

long period hi gain channel

zhi.gif


medium period low gain channel

zlo1.gif

http://www.sydneystormcity.com/seismograms.htm
Dave
 
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Ohhh I discovered that buried in the huge signal of the 7.8, there is a M 6.5 off the coast of northern California
Its P wave arrival is at 15:20 UT. where as the P arrival of the 7.8 is at 17:44 UT

so some calc's ... Calif quake origin time 14:50UT ( to nearest minute) and arrival in Sydney Australia at 15:20 (to nearest minute)

P travel time = 30 minutes x 60 = 1800 sec
across Earth's surface distance (from google Earth) 11,834 km

11834 / 1800 = 6.57 km / sec which fits pretty well with the standard models Dave
 
And a 6 in China. The total list is pretty long, even within the last 24h. Is it true, that media nowadays only report those > 6.8? Did this change in comparison to say, the 80's?
 
fresh_42 said:
And a 6 in China. The total list is pretty long, even within the last 24h. Is it true, that media nowadays only report those > 6.8? Did this change in comparison to say, the 80's?

I did record that M5.9 (6.0) in China yesterday, it was a pretty small signal

The media usually only cover those that were felt / caused damage. There's many significant events that go unreported ( in media) because of their remote location. The media do report a lot more than in days gone by, mainly because global media coverage has improved so much over the last 30 years.
It has the effect of making people think that there are more big quakes than there used to be. But that isn't the case.
On avg ( world wide) per year ...

1 x M8.0 +
18 x M 7.0 - 7.9
~120 odd x M 6.0 - 6.9
~ 800 x 5.0 - 5.9

and these figures haven't changed in the last ~ 150 years of systematic written records. ~ 100 years of instrument recordsDave
 
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