Posts: 10,227
Threads: 345
Joined: Apr 2009
MarkD,
"The article was written in 2009. Make that now 44 years with no big tsunami to strike Hilo. Are we not statistically overdue?"
You're not wrong by saying we're statistically overdue, but the point I was trying to make is that you can't use statistics alone to predict future events. You need to understand all the physical mechanisms as well.
Posts: 785
Threads: 6
Joined: Apr 2012
In this case, we understand the mechanism, but there is such a high degree of uncertainty/variability in the frequency, that, for all intents and purposes, the recurrence interval doesn't have much meaning. " The recurrence interval is every 55 years +/-300/49 yrs".
It is the same situation for Mauna Loa - but we don't have a long enough time frame to know what the average recurrence interval is. Was the 5 year recurrence interval during the last ~300 or so years anomalous compared to the prior 10,000 years? I can't say that we know with any certainty... We could have a flow rolling down the SW flank of Mauna Loa next week (although not very likely), or not for another 100 years...
Posts: 10,227
Threads: 345
Joined: Apr 2009
Latest news via West Hawaii Today:
"
Mauna Loa continues to show signs of unrest, but activity at the world’s largest active volcano appears to be slowing down."
http://www.westhawaiitoday.com/2018/02/1...n-of-late/
Posts: 10,227
Threads: 345
Joined: Apr 2009
For those who have the interest and time, a new Nova episode has just ended on PBS this evening - "Prediction by the Numbers". It's all about probability and quite relevant to the discussion here. The video is available online here:
http://www.pbs.org/video/prediction-by-t...rs-hg2znc/
I want to add something to the program's description about "p-values". The narrator said a p-value of 0.05 was statistically significant and means 95% of the time the result of a prediction or experiment is true. Some fields use that number (in particular, medicine), but it's misleading. In my own field, we use a p-value of 0.0000001, in other words, if you repeat the experiment over 3 million times, you'll likely get a significantly different result just once.
Posts: 998
Threads: 30
Joined: Feb 2012
For the eruptions between 1843 and 1984, the mean time between eruptions is 8.8125 years with a standard deviation of 6.3 years. This would give 8.3 years +/- 12.2 years expected time between eruptions with a 95% confidence level.
Caveat: the sample size of 17 times between the 18 eruptions is less than the 30 observations required to be statistically relevant, so the confidence level is kind of like the pirate code in this case - more a guideline than a reliable statistic. If anyone has the dates of the hundred and fifty or so prehistoric flow dates we can crunch some more reliable intervals. I'm sure someone at USGS HVO has done this at some point.
edit: initial calculation was off by just a bit with spread sheet, checked with statistical calculator - used n=16 instead of n=17.
Me ka ha`aha`a,
Mike
Me ka ha`aha`a,
Mike
Posts: 735
Threads: 20
Joined: May 2006
This link shows info on past eruptions and lava flows from the pleistocene, over 10,000 years ago.
Digital Database of the Geologic Map of the Island of Hawai‘i
https://pubs.usgs.gov/ds/2005/144/
Posts: 40
Threads: 2
Joined: Dec 2013
[quote]
Originally posted by TomK
For those who have the interest and time, a new Nova episode has just ended on PBS this evening - "Prediction by the Numbers". It's all about probability and quite relevant to the discussion here. The video is available online here:
http://www.pbs.org/video/prediction-by-t...rs-hg2znc/
Thanks for sharing the link. It does translate some concepts to make them more accessible to the viewer. Since we are influenced so much by big data and data science, we have to understand more and more to survive. I just wonder if there is enough data to predict when even .05 accuracy the behavior of Mauana Loa?
Posts: 10,227
Threads: 345
Joined: Apr 2009
"I just wonder if there is enough data to predict when even .05 accuracy the behavior of Mauana Loa?"
Well, give its current state since 1984, I would suggest that no, we can't predict its behavior just using stats!