Tsunami Warning Dry Bags
The spring of 2006 The Volcano Augustine near the Mouth of the Cook Inlet was showing some activity. The folks at the Tsunami Warning Center in Palmer, AK asked us to build these simple dry bag devices. The idea was to anchor pressure transducers on the floor of the Cook Inlet, and if a Tsunami did come racing up the Inlet as a result of volcanic eruption, or earthquake, the pressure would go up due to the pressure of the water on top of the transducer. We are still waiting to hear if this has tested successfully or not.
Here is what they said in 2011 about the bags.
Hi Jack,
In 2006 you made some enclosures for me that were called transducer bags. They were made of PVC, and had a PVC pipe fitting at one end. Essentially it looked like a [heavy-duty] hot water bottle for body ache therapy. We have had only three opportunities to use these soft enclosures in the ocean with a sensor enclosed within them. In real applications, the bags you made were never retrieved, as the cable connecting them broke. It used to be that the sensor itself was the weak link in these applications, but the enclosure you made eliminated the vulnerability of the water pressure sensor inlet, and the weakest point of the installation became the cable.
I have had a sensor enclosed in a bag that was left outside in the sun and elements for 5 years and I removed the sensor today. While this bag was never installed at the ocean it was undisturbed and exposed all these years in temperatures from high 80’s to the -20’s. The sensor looks new. The bag is flexible and strong. The seal you made around the PVC pipe fitting was as good as the day it was made. The bag had 1 quart of polypropylene anti-freeze in it all this time. I still have several years of use left in this bag.
I wanted to let you know that the material and construction of these custom enclosures you made have the strength and durability that the Tsunami Warning Center requires for the environment of tsunami monitoring.
Michael Burgy
Senior Electronics Technician
West Coast/Alaska Tsunami Warning Center