Meteor Airbursts and their effect on cetaceans at the surface

Note: I removed the math from this to make it easier to read. I have placed the summary first, which covers the findings; however, read on if you want further information.

Summary: Whales at or breaking the sea surface face substantially increased risk from a meteor airburst compared with fully submerged animals. Surface exposure eliminates the large air–sea impedance loss for the portions of the animal in air, allowing the full airborne overpressure and impulsive loading to act on the blowhole, respiratory tract, and dorsal tissues. Open airways provide a direct coupling pathway for pressure impulses into pulmonary structures, and the impulsive loading of the middle/inner ear and soft tissues increases the likelihood of trauma or temporary/permanent auditory effects. Crucially, surface exposure also magnifies behavioral risk: a sudden, intense airblast can provoke a strong startle or panicked flight response while simultaneously producing surface jets or hydrodynamic forcing that physically displace animals into shallow water or drive them toward shore. Therefore, while large-scale hearing injury from airburst-coupled underwater signals remains uncommon except near energetic epicenters, the combination of direct airblast effects and behavioural consequences makes presence at the surface a significant risk factor for strandings.

If whales are at the surface when an airburst occurs, the risk goes up — sometimes substantially — because they can be exposed directly to the airborne blast (no −30 dB air→water penalty) and because the blast can act on the animal’s blowhole, lungs and sensory organs. Direct air exposure: A whale at or breaking the surface presents air-facing tissues (blowhole, rostrum, dorsal area) that receive the full airborne overpressure and impulse. There is no large impedance mismatch loss for those parts — the animal is effectively in the same medium as the source. Open airways: If the blowhole is open or the animal inhales/exhales at the time, the airway and lungs can be coupled to the airblast — increasing risk of barotrauma and blunt pressure effects. Combined loading modes: The animal may simultaneously receive (a) direct airblast loading of soft tissues and lungs, (b) an underwater pressure pulse on submerged portions, and (c) sudden surface motion (wave/jet) that can move animals onto reefs. Direct blast overpressure on tissues — can cause hemorrhage, tissue shear, trauma to lung and middle/inner ear if sufficiently large. Airway/lung coupling — an open blowhole or inhalation path lets the pressure impulse enter the respiratory tract, increasing internal pressure transients. Rapid vertical acceleration / surface jetting — an airburst over or near the water can launch surface waves, jets or water jets that physically displace animals or force them ashore. Startle / behavioral panic — an intense sudden air-noise and shock can trigger strong flight or grouping responses; boats, shallow bathymetry, or confusion can then cause stranding. Combined stressors — simultaneous geomagnetic, visual (bright flash), or social confusion increases probability of maladaptive behaviour. Blowhole & airway: Airblast through an open blowhole can transmit pressure into the lungs and lower airways; rapid positive/negative swings increase barotrauma risk. Middle/inner ear: Sudden pressure transients can damage hearing—even at lower levels—if the pressure waveform is steep and impulsive. Lung/air sac differences: Cetacean lungs and accessory air spaces are structurally different to terrestrial mammals; vulnerability to blast is not identical and is poorly quantified in the literature. Behavioral consequences: An intense airblast when the animal is at the surface is also the most likely context for a strong flight reaction (fast, disorganized movement) which can lead to stranding in shallow water. Hearing injury (TTS/PTS): still probably uncommon except very near a large airburst epicenter. However, surface exposure increases the chance relative to an entirely submerged animal because of direct pressure spikes to airways and ears. Acute barotrauma / lung injury: possible in high-overpressure scenarios (near epicenter; low altitude burst). The exact probability is unknown because cetacean-specific blast-injury thresholds are not well characterized. Behavioral/stranding risk: substantially higher when animals are at the surface because a strong startle + sudden surface motion + proximity to shore/shelf can combine to produce strandings.