

Last 48 hours in Kathmandu – a Mathematician's analysis of the earthquakes - anaxag0ras
http://younghamlet.blogspot.com/2015/04/attempt-at-some-words-of-calm-through.html

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stevewilhelm
USGS Aftershock Forecast for the Magnitude 7.8 Nepal earthquake of April 25,
2015

(as of April 26, 2015) In the coming week, USGS expects 3-14 M≥5 aftershocks
of the magnitude 7.8 Nepal earthquake. Additionally, USGS estimates that there
is a 54% chance of a M≥6 aftershock, and a 7% chance of a M≥7 aftershock
during this one-week period. After this, in the following month and then the
following year, USGS expects several M≥5 aftershocks, with a significant
chance of M≥6 aftershock (greater than 50%). The potential for an aftershock
larger than the mainshock remains, but is small (1-2% in each time period).

Felt earthquakes (i.e., those with M≥ 3 or 4) will be common over the next
weeks to months. Based on general earthquake statistics, the expected number
of M≥ 3 or 4 aftershocks can be estimated by multiplying the expected number
of M>=5 aftershocks by 100 or 10, respectively. The expected location of the
aftershocks will be in the zone of current activity and at its edges.
Currently aftershocks are occurring in a zone extending approximately 200 km
away from the mainshock epicenter.

This information is preliminary and subject to change.

from
[http://earthquake.usgs.gov/earthquakes/eventpage/us20002926#...](http://earthquake.usgs.gov/earthquakes/eventpage/us20002926#general_summary)

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jjwiseman
This is not a great analysis, and is kind of confusing.

    
    
      Things will improve, the law of math promises it.
    

Ah well, if a mathematician says the law of math promises it!

See Omori's law (and Båth's Law and the Gutenberg–Richter law), and the
roughly 5% chance that this quake was a foreshock for an even bigger quake
("the 2002 Sumatra earthquake is regarded as a foreshock of the 2004 Indian
Ocean earthquake with a delay of more than two years between the two events")

~~~
NZ_Matt
Agreed. Earthquakes are extremly unpredictable, the best we have is the USGS
models and even then they provide very little information.

In Christchurch, New Zealand the M6.3 aftershock in February 2011 was far more
destructive than the initial M7.2 event that occured 5 months earlier. This
was because the epicenter of the February aftershock was significantly closer
to the city and populated areas.

Looking at the Nepal aftershock sequence map [1] it is a concern that many of
the aftershocks are located closer to the populated areas. I really hope that
Nepal has had the worst of it but it would be a mistake to rule out the
possibility of another major event.

[1] [http://www.latimes.com/visuals/graphics/la-fg-g-nepal-map-
qu...](http://www.latimes.com/visuals/graphics/la-fg-g-nepal-map-quakes-and-
aftershocks-20150425-htmlstory.html)

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lostlogin
The magnitude isn't everything, Christchurch NZ being a case in point. It's
later, shallow earthquake caused much more destruction and killed many, while
the bad initial quake killed no one directly. I'm no expert, but the magnitude
of the quake is relative to the depth in a way that masks the actual
destructive power.

