Predicting Whale Strandings

whales stranded in Australia
You can predict whale strandings!

Predicting whale strandings 3 weeks in advance is easy if you have a bit of computer talent and a little background on why toothed whales mass strand themselves. Here’s what you must know first:

Seaquakes Cause Whale STRANDINGs

Only those odontoceti pods that feed primarily on squid above seaquake active mid-oceanic ridges live strand en mass. For every earthquake on land, nine occur in the seabed. For every nine that occur in the seabed, eight of them occur along the rift valley of mid-ocean ridge system–the feeding grounds of the pelagic species that mass strand themselves. In other words, roughly 85% of all earthquakes that have occurred on our planet over the last 30 million years, has occurred in the backyard of the whales and dolphins known to consistently mass strand.

Now read: NAVIGATION FAILURE IN MASS STRANDED WHALES  At this site you will learn all about how seaquakes destroy the echo-navigation system in odontoceti, causing them to swim blindly into beaches downstream from the point of injury. Predicting whale strandings in advance would require that you know where pods of toothed whales and dolphins are usually found feeding on squid above mid-ocean ridges. Once you know where the whales feed, then you can watch the area for dangerous seaquakes.

In my 50 years working to solve the mystery of whale beachings, I have been able to trace back upstream and find an extremely shallow seaquake (averaging ~5.2 magnitude) has occurred ~2,600 miles up current and about 27 days before every mass whale beaching. This means your first job in predicting whale strandings is to trace the surface currents upstream until you find a mid-ocean ridge system. I use a simple system sponsored by NOAA called OSCAR (link). You will need to sort out how to run the software.

Once you find the upstream seismic hotspot, then you need to search for any nearby earthquakes. I use the IRIS EARTHQUAKE BROWSER (link).  You can draw a rectangle around your suspicious area and set the dates and a few limits and come with the whale-dangerous seaquakes within your time frame and distance upstream. Again, you figure out how to use this software.

Use the Guidelines Below:

The size of the average quake associated with a mass stranding is ~5.2 magnitude. I believe quakes below 4.5 mag. and above 7 mag. do not injure pods of whales because (a) events less than <4.5 are too small, and (b) events above >7 give off precursor signals easily detected by the whales in time for them to move out-of-the-way. This page will give you an idea of the level of energy released by your selected event (link).

Richter           TNT             Example
Mag.               Energy

2.0                        1 ton      Large Quarry or Mine Blast
2.5                   4.6 tons
3.0                    29 tons
3.5                    73 tons
4.0               1,000 tons     Small Nuclear Weapon
4.5               5,100 tons     Average Tornado (total energy)
5.0             32,000 tons     TNT Equivalent
5.5             80,000 tons     Little Skull Mtn., NV Quake, 1992
6.0         1 million tons     Double Spring Flat, NV Quake, 1994
6.5         5 million tons     Northridge, CA Quake, 1994
7.0       32 million tons     Largest Thermonuclear Weapon
7.5     160 million tons     Landers, CA Quake, 1992
8.0           1 billion tons     San Francisco, CA Quake, 1906
8.5           5 billion tons     Anchorage, AK Quake, 1964
9.0         32 billion tons     Chilean Quake, 1960

Keep in mind that 90% of the seaquakes that injure whales are shallow focused, showing up in data as no deeper than 10 km below the ocean’s surface. No event focused deeper than 20 km has ever been associated with a stranding. The reason is that the energy from the quake’s focus spreads out in a 360-degree circle; some going down deeper, some traveling horizontally and some spreading vertically towards the rock-water interface. Spreading weakens the energy that would arrive at a particular point on the seafloor. For this reason, the seismic waves from a quake with a hypocenter 20 km deep in the seabed spread out in a very large circle before reaching the rock-water boundary. The spreading would be severely attenuated and fractionated by the crustal structure, especially by the inhomogeneous fractures near the surface. For this reason, you should not consider seaquakes focused deeper than ~15 kilometers.

About 1,500 shallow seaquakes above 4.7 magnitude occur annually along the 65,000 km-long mid-oceanic ridge system, the primary feeding grounds for the species that consistently mass strand.

The energy of a magnitude 4.5 event is equal to 120 thousand pounds of C4 plastic explosives while a magnitude 6 event is equal to 120 million pounds of C4. The closer to the rock-water boundary this energy is released, the more danger to diving, air-breathing mammals. Thus, a magnitude 4 .7 event only 3 km deep in the crust will likely be just as dangerous as a magnitude 6 event at a depth of 10 km. The average thickness of Earth’s crust below the continents is ~45 km, while the average thickness of the oceanic crust below the mid-oceanic ridge system is only 7 km, and composed of a much simpler and more uniform basaltic structure. However, when the vibrations from an undersea earthquake propagate through the thin crust of the mid-oceanic ridge into the homogeneous medium of water, there is far less attenuation and thus, more seismic energy enters the sea, creating a greater danger to whales diving near the bottom.

Reasons Why PREDICTING Whale StrandingS Fail

(1) The danger zone above the epicenter might not contain any whales.

(2) The quake might have induced ambient pressure changes too weak to overcome the counterbalancing mechanisms these animals have evolved to deal with earthquake activity. This would explain why earthquakes below <4.7 magnitude are not associated with beachings. Moreover, because water does not transfer shearing motion, strike/slip events with predominate side-to-side motion are not nearly as whale-dangerous as events with mostly vertical jerking. Furthermore, the energy that generates rapid and intense pressure changes is not the magnitude of the quake. Rather, what causes whale-dangerous quakes is the speed of the vertical shifting in the seafloor (peak ground acceleration). In other words, scientists can not claim the seaquake theory is invalid just because there were no strandings following a particular earthquake.

(3) There might have been a series of smaller foreshocks hours before the main shock that scared the whales from the area. If the main shock was more than 1000 km from the nearest seismic station, these foreshocks, especially before major events, might have gone undetected and not recorded in the earthquake data.  Additionally, high-frequency acoustic emission (micro-cracks) are known to start several days before the main shock (ref 1). Whales may interpret these signals as a warning and move away. These acoustic precursors are known to diminish several hours before the main event so that pods diving above the epicenter 10 minutes before the quake, might be caught by surprise. Keep in mind that whales would never have flourished in the ocean had they not developed a means of detecting dangerous events. However, whatever is their life-saving signal, it is high unlikely that it is fool-proof.  Evolution is a balance between many forces and dangers and is never perfect.

(4) MY group suspects that many species of whales can sense geomagnetic precursor signals and will scamper away hours to days before major shocks occur. Most quakes above ~6.7 mag. are known to emit these signals, which may explain why whales never beach after big earthquakes. Geomagnetic signals remain high in the area for many weeks after a major shock and would signal whales to avoid the area until the seafloor is more stable.

(5) Seaquake-injured whales might recover if their injuries are minor. Whether or not recovery is possible depends on the degree of their injuries and on how lucky they are to catch a meal on the surface to sustain them while they heal. Several hundred years ago, most seaquake-injured pods recovered because the surface waters were teeming with schools of small fish. These pods held no acoustic memories of the seabed scenery between the time of their injury and recovery so they were not able to backtrack to their earlier feeding grounds. This long period of disorientation forced them to find a new habitat. Thus, 200 years ago, seaquakes were evolutionarily helpful because they spread the species and prevented overgrazing on a particular feeding ground. This has all changed now due to human overfishing. Not finding food on the surface to help them heal explains why more pods are beaching today than did at any time in the last several million years. Seaquakes along may wipe out pelagic species if our whale scientists continue to ignore barotraumatic injuries in whales.

(6) Sharks or killer whales might take seaquake-injured whales before they reach the beach, especially if their injuries are severe. These top ocean predators feed on whales, not minnows. A moderate seaquake would serve as a dinner bell.

(7) Surface currents might guide the pod away from shore and out into the open ocean where they eventually succumb to predication. Surface currents might also guide the non-navigating whales into the path of ocean-going vessels, navy ships using powerful sonar, oil industry seismic survey vessels, or into fishing nets. Unable to find a safe path to avoid further injury, seaquake-injured whales would be vulnerable to additional injury and likely death.

(8) The injured whales might strand on a remote beach and not be discovered.

(9) A storm at sea might split the pod into several smaller groups which will then strand at different beaches and different times. Smaller groups also make easier pray for sharks and killer whales.

(10) Native folks might harvest the stranded whales and not report them to the authorities. Eating live-stranded seaquake-injured whales was common up until a hundred years ago.

(1) E. V. Sasorova, B. W. Levin, and V. E. Morozov, 2008, Hydro-seismic-acoustical monitoring of submarine earthquakes preparation: observations and analysis. Advances in Geoscience, Adv. Geosci., 14, 99–104, 2008