09 September 2012

TWO QUAKES CAUSE NEAR BEACHING IN CAPE VERDE ISLANDS


August 2012:  The Cape Verde mass stranding of 17 pilot whales took place on Santa Maria Beach (Sal Island 16.590N; 22.900W) during early morning hours on August 24, 2012.  The rescuers were able to push the whales back into deep water and they swam off with the surface flow.














These whales were easily rescued because the depth of water at this beach drops off rather quickly due to beach erosion by currents that run parallel to the shoreline at Santa Maria Beach. In other words, this beach is not your stranding-typical, gradually-slopping beach. You can see the water quickly gets deeper near the whales in the pictures. You can also see that the whales are swimming from left to right indicating that the current was flowing west (to the right) and along the shoreline.

The two quakes that injured this pod occurred along the Central Mid Atlantic Ridge, just north of the equator at: 4:49N; 32:73W. The first event was a shallow, thrusting, magnitude 5.3 event; a quake most likely to injury diving whales.  http://www.emsc-csem.org/Earthquake/earthquake.php?id=279748

The second event was a magnitude 4.9 occurring 17 minutes later.  http://www.emsc-csem.org/Earthquake/earthquake.php?id=279750#summary

As you can tell by the color code of the small red seismic balloons, the earthquakes at the red star (4:49N; 32:73W) are all thrusting events and the most dangerous to diving whales.  If you look at the circles of the events at 7N, you can see that these are mostly strike/slide quakes with side-to-side motion, which are less dangerous.


Assuming the 17 pilot whales were injured by the two events mentioned above, how did they get from the epicenter to the stranding beach?

I should first remind my readers that the rapid and excessive pressure changes in the water when the seafloor danced up and down, induces a barotraumatic injury in the sinuses and air sacs inside the heads of the whales. Intact and functional sinuses and air chambers are an absolute must for the proper function of each whales biosonar system; thus, sinus barotrauma instantly knocks out their ability to navigate and also prevents diving and feeding due to intense pain.

Drag forces when swimming against the flow of the current quickly point the streamlined bodies of the lost pod headfirst with the flow and downstream they go!  So to determine how that got from the Central Mid-Atlantic Ridge to Sal Island in Cape Verde area, we need to trace the surface currents from the Ridge at 4:49N; 32:73W.

The fastest way is by using the OSCAR system at:  http://www.oscar.noaa.gov/datadisplay/oscar_latlon.php


As you see above, there is a strong eastward flow from the epicenter area to the Senegal coast about 1,200 miles downstream.  Now we need a close up to see the local currents.......


Surface currents near the Senegal shore are complicated and depend on upwelling condition and local storms, and etc. The strongest flow in the chart about can be found at 10N.  Since the faster flow will cause less drag, the whales will naturally move into the water flowing the fastest. You can still see that there is a fair chance that the pod turned north near the shoreline and went back in the opposite direction. A close up look at OSCAR above will show that there is indeed a northern flow that would have carried the lost pod the Sal Island.

What we need to show absolute proof is local weather conditions.  We can see in the pictures above that there were stormy conditions during the beaching.  Hopefully, we some help, we will be able to show local conditions in future strandings.  My time is too limit now to do any batter than you see here.


Capt David Williams
Deafwhale Society, Inc

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2015
Dec 09: Whale Dangerous Earthquake South of Perth 
Dec 09: Seaquake causes dolphins to strand Baja California   
Nov 23: Seaquakes kill 322 baleen whales in Chile    (shocking)  
Aug 24: NOAA whale scientists dumbfounded   
Aug 14: stranded dolphin is determined to be deaf   
Aug 08: seaquake causes pilot whales to strand Nova Scotia   
Jul   27: is our stranding solution flawed as scientists claim   
Jun  01: pilots stranded Isles of Skye from Reykjanes Ridge   
May 22: dead whales washing ashore on the California Coast   
May 10: earthquake kills 20 Sei Whales near Chile Coast   
Apr  10: seaquake strands 150 melon-headed whales in Japan   

2014   
Dec 25: navigation failure in mass stranded whales  (most popular)   
Dec 08: seaquake causes 7 sperm whales to beach Australia   
Nov 24: seaquake beaches 3 sperm whales at Golden Bay   
Nov 04: seaquake beaches 60 pilot whales in Bay of Plenty   
Oct 29: nine pilot whales strand on Prince Edward Island   
Apr  11: 60 pilot whales beach in Bay of Plenty   
Mar 20: Cape Ray Newfoundland 37 dolphins beach   
Mar 14: undersea quakes louder than nuclear explosions   
Mar 13: seaquakes cause whale strandings 32 million years   
Mar 02: blue whale killed by seaquake in Kuwait   
Feb 27: seaquake kills young killer whale   
Feb 23: predicting mass beachings based on seaquakes   
Feb 21: lessons in understanding why whales beach   
Feb 18: seaquake Greenland Sea kills 3 sperm whales   
Feb 12: nine orcas killed by seaquake   
Jan 30: Cape Cod mass stranding predicted   
Jan 20: seaquake causes 39 pilot whales to strand Florida   
Jan 16: seaquakes beach 65 pilot whales in Golden Bay   
Jan 05: seaquake beaches 30 pilot whales in Golden Bay   

2013   
Dec 06: why did pilot whales beached in the everglades?   
Apr 30: seaquake beaches 6 killer whales in Iceland   
Apr 25: beached whales stop war games   

2012   
Dec 08: seaquake beach pilot whales South Carolina   
Nov 15: pilot whales beach at Golden Bay, New Zealand   
Nov 04: seaquake causes two pods to beach at King Island   
Oct 28:  pilot whales strand on North Andaman Island   
Oct 17: earthquakes cause New Zealand whale stranding   
Sep 09: earthquake kills pregnant sperm whale   
Sep 03: seaquake strands pilot whales in Scotland   
Aug 24: two quakes cause near beaching in Cape Verde   
Jul  28:  200 Pilot Whales Northwest of Iceland   
Mar 19: Four Sperm Whales Wash Ashore in China   

2011   
Dec  31: world's rarest whales killed by earthquake   
Mar 06: 52 melon-headed dolphins strand in Japan   

2008   
Nov 20: 52 Pilot Whales Stranded in Tasmania


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