Monday, January 18, 2016

Tsunami recorded on 1/17/2016? or just bad reporting?

Around 7am this morning I noticed a weird link in my newsfeed about a tsunami warning yesterday 1/17. It comes from a fake news site that put out misleading articles for clickbait. I couldn't find any other links or sources so I decided to check the gauge myself. Sure enough there it it on DART Station 46404. The buoy itself is designed to monitor tsunamis and it did register a tsunami "event". The only problem is that this "event" was only a six cm drop in sea level. It was also in the middle of a huge thunderstorm. At this time it appears that no statement has been issued from NOAA or the USGS. It looks like the NTWC (National Tsunami Warning Center) has not issued anything on it.
Link to article

On Sunday 1/17/2016 the seas were pretty rough out there at the time in question but it appears that the buoy did record a small drop in sea level at the time. I checked the other nearby buoys and they did not trigger any event recordings but they did show some rough seas.
Event data from buoy 46404

The closest DART buoy 46407 to the south did record a bit of a discrepancy around the same time 46404 did, which is interesting but not significant. There was a large storm moving through the area and I suspect the pressure gauge was just reading the storm. The metadata indicates that

"The data are recorded in pounds per square inch absolute (PSIA), but are displayed in meters of water after applying a constant 670.0 mm of water/PSIA conversion factor."

I bet this is the source of the discrepancy. The storm was pretty big triggering flood warnings across the Pacific Northwest.

Buoy 46407 data. This shows a bit of a difference in ocean height but not much.

After reading the article more in depth the author has made a fatal error in interpreting the data:

"As of 0231:30, the initial water column height is 2738.80 Meters deep (8985.56 feet).  Two minutes and thirty seconds later, that same water column height had dropped to 2738.66 Meters deep (8985.10 feet).  Where did the four inches of water disappear to?  Answer:  The earth sunk; and continued to sink for the next several HOURS.  As you can see from the second chart above, from 0230 GMT to 0600 GMT, the ocean continued to sink to 2737.7 meters deep (8981.95 feet).  The buoy is too far away from shore to be affected by high/low tide, so where did the four feet of ocean water disappear to?"

The key phrase here is "The buoy is too far away from shore to be affected by high/low tide". This is incorrect and the buoy clearly shows the tides moving in and out. The buoy did register four inches of drop but that is not anything significant. He asserts that the ocean continued to drop another four feet. This was just the tide going out. So it appears after reviewing the data that this is a non event and just a case of bad reporting and misinterpretation of raw data....

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