At 07:59 PM 5/11/2003 -0700, Art Botterell wrote:
>[...]
>II - Automated Origination by Sensor System
>
>Along a popular Northwest beach a series of automatic tsunami sirens have
>been installed. In the base of each siren is an accelerometer and a
>computer with a GPS receiver. All of these devices are linked by a
>wireless local area network.
>
>When an individual unit detects what appears to be a P-wave/S-wave
>sequence that might indicate a near-shore earthquake, it generates a CAP
>message containing its location, the precise time of the P-wave's arrival,
>and the estimated distance of the epicenter based on the P-wave/S-wave
>interval.
>
>Each computer in the network correlates all the messages received from the
>other instruments (which form what amounts to a phased array) and, if the
>pattern of messages suggests a near-shore quake (and not just a truck
>driving down the coastal highway) then each siren activates. In addition,
>one of the instruments assembles a "summary" CAP message describing the
>event and feeds it to regional and national seismic networks.
>
>(Based on an idea shared by David Oppenheimer at the USGS in Menlo Park.)
How about this, simplified, version:
A set of automatic tsunami sirens have been installed along a popular
Northwest beach. The sirens are triggered by a wireless network of sensor
devices. Each sensor generates a CAP message containing its location and
the sensed data at that location that is needed for the tsunami
determination. Each siren activates when a tsunami determination is made.
In addition, a network component assembles a "summary" CAP message
describing the event and feeds it to regional and national tsunami networks.
