I can't find the listing in the USGS for this one yet, but I suspect most of their range of uncertainty is generally in the horizontal scale. The depth usually says it's fixed by program algorithm. Maybe you can share press release?
Josh
-----Original Message-----
From: Tectonics & structural geology discussion list on behalf of Malcolm McClure
Sent: Fri 1/21/2005 12:31 PM
To: [log in to unmask]
Cc:
Subject: Re: RE : Earthquake
Now we are discussing something really interesting. There was a 5.4 in
the Nicobar islands yesterday (happens in UK on average every 8 years).
USGS says depth was 26.9 km., plus or minus 27.2 km. The upper limit
for this earthquake was apparently about 300 metres above sea level.
Can someone please explain?
Malcolm McClure
On 21 Jan 2005, at 17:45, Musson, Roger MW wrote:
> Actually aftershocks seldom if ever produce tsunamis. Either they are
> too small, or in the case where a tsunami is related to the dislodging
> of seabed sediment, all the loose stuff has already gone in the main
> shock.
>
> In this case the largest aftershock was 7.3, very soon after the main
> shock. The rest were 6s at best. The difference in tsunamigenic
> potential of a 6.5 earthquake with perhaps 20 km length of fault
> movement, compared to a 9 with 1200 km of rupture, is immense. The
> critical issue in this disaster is that the main shock was really
> extraordinarily huge. The way the magnitude scale ascends rather
> disguises the immensity of a 9 until you start looking at it in other
> ways (like size of rupture).
>
> Roger Musson
>
> British Geological Survey
> West Mains Road
> Edinburgh EH9 2NA
> Scotland
>
> tel:+44-(0)131-650-0205
> fax:+44-(0)131-667-1877
> email: [log in to unmask]
>
>> -----Original Message-----
>> From: Tectonics & structural geology discussion list
>> [mailto:[log in to unmask]]On Behalf Of Malcolm McClure
>> Sent: 21 January 2005 17:33
>> To: [log in to unmask]
>> Subject: RE : Earthquake
>>
>>
>> Sad, really, that when 250,000 people die as a result of a tectonic
>> disturbance, the assembled leading world's experts on tectonics can
>> tell us how many angels can dance on the head of a pin, but
>> still can't
>> explain why the 9.0 produced a tsunami but several major aftershocks,
>> all along the faultline didn't, apparently, produce mini-tsunamis.
>>
>> Malcolm McClure
>>
>
>
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