(a pressure-related injury in the sinuses and air sacs)
Induced by Undersea Earthquakes, Explosive Volcanic Eruptions, Sonar, Seismic Airguns, and Explosives Cause Whales To Beach Themselves
THE SOLUTION TO THE MYSTERY OF WHY WHALES BEACH!
by Capt. David Williams, Chairman
Deafwhale Society, Inc
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The actual earthquakes responsible for recent mass beachings: WORLD'S RAREST WHALES 31 Dec 2010 King Island Australia 4 Nov 2012 Andaman Islands 21 Oct. 2012 New Zealand 14 Oct. 2012 Scotland 02 Sept 2012 Florida 01 Sept 2012 Cape Verde 24 Aug 2012
The species of toothed whales and dolphins known to consistently mass beach themselves primarily feed on squid and small fishes that flourish in great schools along the 65,000 km-long mid-oceanic ridge system. Mid-ocean ridges are by far the most seismically-active places on earth. Ninety percent of our planet's earthquakes and volcanoes are located in the thin crust that forms the rift valley of this volcanic mountain range.
Regardless of the above, there has never been a scientific inquiry into earthquake-induced barotrauma as the possible answer to the centuries-old mystery of why pods of whales and dolphins beach themselves.
INJURIOUS UNDERSEA EARTHQUAKES
Seaquakes can be an awesome force in the water (more on seaquake intensity). The pressure jump behind the front of such seismoacoustic waves can attain 1.5MPa, or 15 atmospheres above ambient. The vertical component of the floor-displacement velocity is estimated at about 10-100 cm/s, the accelerations of floor motions can amount to about 10 m/s² and the area of dangerous oscillations might attain 100 square km (ref).
Encounters with seaquakes have been reported by sailors for centuries (1750-1899) (1900 to 2012). The Deafwhale Society dug up thousands of seaquake/vessel encounters just to prove beyond even a slitter of doubt that seaquakes are indeed dangerous to both ships and diving whales. Our point in presenting these seaquake encounters is simple: if a seaquake in the seabed can shake a ship on the surface so violently that the crew is frightened out of their wits, seaquakes can certainly induce barotraumatic injury in an entire pod of diving whales.
But not all undersea earthquakes are dangerous. Both pressure (P) and shear (S) waves radiate outwards from an earthquake focus in all directions in the solid seabed before reaching the rock/water interface. The deeper the focus of this energy, the more it spreads out in the solid earth, the less the water is disturbed. In general, quakes focused deeper that ~20km are harmless to whales. So are larger earthquakes above ~7 magnitude harmful since major events usually give off strong precursors signals easily detected by the whales many hours, and sometimes days, before the quaking starts (ref) (ref). The whales sense the pending earthquake and simple move out of the way before the danger hits. This was the best way evolution had for protecting divers who insisted on feeding in earthquake-prone areas.
Earthquakes of lessor magnitude that erupt without precursors are the ones that catch the whales by surprise.
Based on 40 years of observations by the Deafwhale Society, the most dangerous crustal earthquakes for whales and dolphins are shallow (less than 10km) mid-ocean ridge events between 4.8 and 6.5 magnitude. These quakes erupt suddenly without precursors along either normal, reverse, or thrusting faultlines.
The events responsible the most pod beachings also appear to be associated with volcanic hot spots and hydrothermal vent fields along the rift valley of mid-oceanic ridges, whereas the quakes along transform faults do not appear to be so whale-dangerous.
There are two reasons why this might be so: (a) pods are drawn to the volcanic hot spots and the hydrothermal vent fields because this is where the squid hang out, and/or (b) this area might be home to a more explosive-type earthquakes and thus stronger seaquakes.
Seismological records reveal that a shallow mid-sized undersea earthquake has occurred along the 65,000 km-long mid-oceanic ridge system on average about 6,000km upstream and 27 days prior to every mass whale beaching for the last 20+ years (see comments on previous mass strandings). Furthermore, these particular events are all located on the primary feeding grounds of the odontoceti species in question. Seismological records also show that there has never been a pod beaching in the last 20 years when there were no suspicious undersea earthquakes within the allowed time frame and distance upstream. And don't think this is just a happenstance observation. These are whale-dangerous earthquakes that occur in specific locations at the right distance and time upstream from the beach. These are not forced matchings—they are bloody obvious pod-dangerous earthquakes that happen in the feeding grounds of the species in question.
On average, a thousand shallow crustal earthquakes between 4.8 and 6.8 magnitude occur annually along the mid-oceanic ridge system.
The energy of a 4 magnitude event is equivalent to 120 thousand pounds of C4 plastic explosives, whereas a 6 magnitude event is equivalent to 120 million pounds of C4 (ref). Obviously, the closer this seismic energy discharges to the rock/water interface, the more intense the seaquakes become, the greater is the danger to diving, air-breathing mammals. It is thought that a 4.8 magnitude crustal event, only 3km deep, could be as dangerous as a 6.8 magnitude crustal event 10km deep. The principal difference would be in the circumference of the danger zone. The hazardous zone for a 4.8 magnitude event 3km deep might be 10km, whereas the circumference of the danger zone for a 6.8 event 10km deep might be 100km.
The average thickness of the crust below the continents is ~45km whereas the average thickness of the oceanic crust in the media valley of the mid-oceanic ridge system is only 7km and composed of much simpler and more uniform basaltic structure. Seismic shock waves being propagated upward from a continental hypocenter at 30km deep would spread out much further and be severely attenuated and fractionated by the crustal structure and in particular by the inhomogeneous fractures near the surface. However, in the case of shocks propagating through the thin crust of the mid-ocean-ridge axis into the homogeneous medium of water, there would be far less attenuation (ref) and thus more seismic energy will enter the water creating a greater danger to whales and dolphins diving near the epicenter.
The percentage of change in pressure, both above and below the ambient water pressure at any given depth, depends on the speed (peak ground acceleration and peak ground velocity) of the vertical thrusting, not on the quake's magnitude. This is so because magnitude is based more of the length of the rupture, not on its explosive characteristics. Whenever the thrusting is relatively slow, the water above the epicenter simply flows to the side before any great pressures build.
You'd be correct to call whales and dolphins "airheads" because about 30% of the volume of their head is occupied with a mixture of air and foam enclosed inside sinuses and air sacs of all shapes, including the pterygoid, peribullary, maxillary sinuses shown in the illustration on the right. The whales also have two middle-ear chambers filled with air. The health of these enclosed air pockets is critical to a diving whale's survival because the air and foam serve to channel sound inside their heads so that their echolocation and echonavigation systems function properly (ref) (ref) (ref). The air is also used to generate acoustic clicks and whistles. (see "The Acoustic Function of the Air Sacs.")
On occasion and without warning, a quake suddenly erupts in the seafloor in which the intensity of the oscillations in water pressure (seaquakes) are too excessive to be counterbalanced by the whales' pressure regulating anatomy. Because the volume of air in the sinuses rapidly compresses and expands during the passing of seaquake waves, while bodily tissues, blood, and bones do not, strong pressure differentials develop at air-filled interfaces causing shear forces that tear, bruise, and disrupt tissues, membranes, and small blood vessels.
Since echonavigation and echolocation are not possible without intact and functional sinuses, air sacs, and middle-ear air cavities, the barosinusitis and/or barotitis renders the exposed pod members unable to use their biosonar to determine their position or to find food. Furthermore, marine mammals with sinus/middle-ear injuries would not be able to dive much deeper than a few meters without suffering intense pain. (read more on barotrauma in whales)
THE LONG JOURNEY TO THE BEACH
A pod of seaquake injured whales/dolphins would huddle together in a tight group for protection against sharks. Without a sense of direction, they would swim away from the point of injury in the path of least drag (resistance). Since water is 800 time denser than air, if the non-navigating pod attempted to swim in any direction except with the surface flow, strong resistance (drag) would turn their streamlined bodies and point them headfirst downstream. Furthermore, since the current guiding the pod is the same energy that carries each grain of sand to build the beach, the odds favor a beach landing, especially in an area where a cape, peninsular, bay, or sand bar extends out to sea opposing the flow of the surface waters. Said differently, surface currents build beaches; surface currents also direct non-navigating whales to these beaches.
The wind, coupled with the effects of the Earth's rotation, determines the direction of the surface flow; however, in coastal waters, the effects of inflow from rivers, the geographical shape of the land, and tidal out flow must also be considered. Non-navigating whales and dolphins, moving downstream with the major offshore currents, are stirred into coastal waters when strong winds shift the surface flow towards land. The odds of a stranding are greatly increased when a strong wind blows shoreward at the same time tidal currents are incoming. On the contrary, beachings never occur when a strong wind is blowing out to sea at the same time tidal currents are outgoing. This observation alone confirms that the whales are not navigating when they go ashore.
The major stranding beaches all around the World have large hook-shaped land masses, sand spits, and/or sand bars that extend out to sea opposing the general flow of the surface current. These areas trap sand, sea weeds, dead whales, and flotsam; the same areas also trap non-navigating whales swimming with the flow.
Whales strand were beaches are building; they do not strand where beaches are eroding.
A non-navigating pod washed into an inlet by an incoming tide will be left in the mud when the tide recedes. Pods that are carried deep into backwater lagoons by tidal inflow are also left on a sand bar or in the mud when the tide ebbs.
When whales re-beach after being set free, the new stranding site is always downstream from the original, proving that once-stranded, whales always swim with the flow of the surface currents. Often, when the wind is blowing toward shore, released whales will turn and come back to the same beach. Rescues appear successful when whales are released in places and during periods when the current is flowing out to sea.
The most important conditions to be noted by observers at the beach are: (a) the direction and speed of the wind, (b) surface currents, (c) tidal condition, (d) color of surface waters, and (e) presents of flotsam.
The time between the injurious seaquake and the beaching is also important for assessing the health of beached pods. Those that strand closer to the time of their injury are usually more vigorous; those that strand during relatively calm, more than 30 days after their injury, are far less likely to recover. Knowing the nature of the injury and when it occurred, coupled with the conditions at sea and on the beach, are important factors for rescuers to assess. (read more on how surface currents pick the stranding beach, not the whales)
THE SHARKS PLAY A MAJOR ROLE
Big oceanic sharks don't feed on tiny fishes. They open their big ugly mouths and bite into a whale's ass and then twist and turn and tear off huge chucks. Sharks trail these wounded pods like wolves trail a herd of elk. They wait patiently for a straggler to fall behind. The injured whales are aware of the waiting sharks so they stay close to their pod mates. Obviously, the pod sticks close to each other not because of a "strong social bond" but out of fear of being eaten alive. The terror they must experience when alone in shark-infested waters explains why injured individuals, when freed, will not swim away from the beach until the rest of the pod is also free. They are not expressing sympathy for their still stranded pod mates; rather, they know the odds that they will be the next shark attack victim is greatly reduced if they swim away with the group. The main reason these whales live in tight social groups is because there is greater safety for the individual.
Nor are seaquake-injured whales following a leader or going to the aide of a sick pod mate. They follow behind each other because they are terrified to be left alone in shark-infested waters. They don't swim away from the beach when set free unless the rest of the pod goes with them for the same fearful reason.
One other point: Shark attacks on swimmers occur far more often when injured whales swim by the coast. Many sharks get pushed away from the chance to feed on a fat whale. They are ravenous—driven nearly mad by hunger. They will go after any thing big enough to eat. Human lives could easily be saved from sharks if the crooked scientists would stop trying to protect the Navy and the oil industry! With the right equipment, periods can be predicted when wounded whales will approach beaches. Shark warming can be posted. Much can be done when the whale scientists stop lying.
EVOLUTIONARY ADAPTATION TO SEAQUAKES
Pelagic odontoceti have thrived for ~50 million years in seismically-active waters. They have surely evolved protective means for dealing with seaquakes . One of the best strategies would be to detect seismic precursor signals and move out of the way long before the main shock. It is well-known that many land dwelling animals exhibit rudimentary precursor sensing skills; however, since nine out of every ten earthquakes on the planet occur under the ocean's surface in the backyard of whales and dolphins, to think that cetaceans can not detect seismic precursor signals seems foolish. In fact, whales are the most likely species to have evolved the greatest skills in detecting earthquake precursors. This would be especially true since seaquake pressure waves are far more deadly to diving sea mammals then ground-shaking is to grazing land-dwellers. (read more on evolutionary adaptation to seaquakes in whales)
The US Navy and the oil industry might be able to mimic or create artificial precursor signals to frighten marine mammals away from dangerous military and oil industry operations. That would solve their problem. I even volunteer my time to show them how to sort it out.
Whales can not drink saltwater any more than you can. Since their freshwater comes from the fish and squid they eat, their greatest challenge is surviving on the surface without water and nourishment long enough to recover from their diving-related injuries.
Evolution again comes into play by equipping whales with a means to go long periods without food and water; however, since seismically-induced barotrauma has been overlooked by marine mammal scientists, so to has the role that evolution might play in aiding their recovery.
It is reasonable to also assume that after an unknown period of rest on the surface, many seaquake injured pods recover and regain their acoustic skills along with the ability to dive and feed themselves. This recovery must surely come in stages. Some pods will recover completely in ~20 days and some in 30 days or even 40 days. At first, the recovering whales and dolphins are able to dive to 5-10 meters, slowly increasing their depth and hunting abilities over time until recovery is complete.
The possibility also exists that pods might be in the final stages of recovery and still beach if strong currents and stormy seas wash them ashore. Said differently, pods that beach in stormy weather may have a better chance of survival than those that beach during relatively calm periods. Recovery also depends on the extent of the original barotrauma and the availability of food on or near the surface.
The injury will not be the same in all members of the pod. The most seriously injured would be removed from the pod by sharks long before the stranding occurs.
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