The U.S. Tsunami Warning System issued a warning after an earthquake
near Alaska at 01-23-2018 09:35:57 UTC:
http://www.tsunami.gov/?p=PAAQ/2018/01/23/p3054t/1/WEAK51
However, when I checked the home page at 11:15 UTC the map did not show
the earthquake location and instead said "Earthquake Layer failed to
load" and "Alerts/Threats Layer failed to load". This would appear to be
because the system was overloaded. I then canceled the page request, not
wishing to make the situation worse.
The NWS Tsunami Alerts Twitter feed was working at the time. However,
the twitter alerts contained a link to the same non-functioning web page.
There were some maps provided direct in the twitter feed, which did
display. However, these maps are difficult to interpret, as they showed
a series of predicted arrival times as colored lines, with no scale as
to the size of the wave. The waves were shown reaching Australia in 11
hours, although no warning had been issued by the Joint Australian
Tsunami Warning Centre.
Colored dots on the map indicated the location of tidal gauges and
"DART". Not explained on the map, DART is a system of "Deep-ocean
Assessment and Reporting of Tsunamis" detectors.
Fortunately in this case the tsunami was only 6 inches high (as reported
by the tidal gauge at Old Harbor Alaska). However, I suggest revising
the design to use simple static map images on the web site, using a few
colors, so the file is small. Also the use of extensive JavaScript
should be avoided to allow the page to load quickly. At present the HTML
file is only 61 kBytes, but the other files are 3.4 Mbytes, including a
1.2 Mbyte JavaScript file.
The tidal gauge and DART locations are not of use to someone who wants
to know when, when and how large a tsunami to expect. These should be
omitted from the map, unless they show a reading. The predicted arrival
time should be limited to a few hours, until the existence of a
significantly sized tsunami is confirmed.
Links at:
http://blog.tomw.net.au/2018/01/us-tsunami-warning-system-problem.html
--
Tom Worthington, MEd, FHEA, FACS CP. http://www.tomw.net.au t
+61(0)419496150
TomW Communications Pty Ltd. PO Box 13, Belconnen ACT 2617, Australia
Liability limited by a scheme approved under Prof. Standards Legislation
Honorary Senior Lecturer, Computer Science, Australian National University
https://cecs.anu.edu.au/research/profile/tom-worthington
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