For the final act of a story I'm building, I'm planning a scene that involves the sudden appearance of fog, along with a small Tsunami, affecting part of the city.
To ask this question, I am going to pose a simplified scenario. Let's say that in the sea we have a submerged object, which I will call Joflu (this is an improvised name at the last minute, don't give it importance). Imagine the Joflu as a sphere 15 meters in diameter, the exact nature of which is irrelevant. Previously in the story, Joflu was exposed to an emission of 12552000 Gigajoules (equivalent to 3 Megatons of TNT), of which it is expected to have absorbed up to 1%, that is to say 125520 GJ, however, we are going to limit it to 0, 25%, so our Joflu stores 31380 GJ. With this said, we establish that Joflu has access to a large amount of energy, but it is not unlimited. It should be noted that you cannot release all this energy together either, but you can do it gradually. Continuing the argument, let's assume that the Joflu has the ability to adapt to harness the energy stored in its body. With this premise, let us establish that when Joflu began his adaptation, the release of energy increased, from a minimum level, to a medium and stable release. However, during the first half of the adaptation process, the release of energy spiked, either due to a higher energy requirement, or due to system failures. I avoid going into details about what form of energy the stored energy belongs to, and the energy released, including the spikes, to give space for more response options.
Finally the stage I wanted to reach. Joflu is submerged at a point with a depth of 55 feet (~17 meters), located 5.4 nautical miles (~10 kilometers) from the coast, and from the coast inland, we have two kilometers of land to the place Where is the observer of this scene? In this extension, we have some obstacles, such as streets, trees, the gradual elevation of the terrain, and small buildings, but in general it is an open terrain. Our observer is in an avenue, at an altitude of 10 meters above sea level. The man is driving his car, on a day like any other, except for his interest in the news of the moment -the previous events in history-, which for him are nothing more than news, like the ones he hears on the radio in that moment, ignoring that the Joflu is 12 kilometers from his location. Simultaneously, the Joflu is adapting to take advantage of its reserves, and has a peak of energy release, 37 seconds later, in the avenue the first effects are felt. Our observer's car shakes slightly but rhythmically, when a rumble, a weak shock wave, reaches the avenue, and the same happens to the other vehicles. Out of a mixture of curiosity and fear of crashing or overturning, he decides to stop his car and get out to look. When doing so, he checks that the noise persists, but the shock wave became a gust of humid wind that carries water vapor. The man does not know what is happening, so he decides to wait a few minutes, during which the blast persists. Eventually, he hears shouts and horns coming from the streets closest to the coast, and as if responding to his doubts, a layer of warm water appears, partially boiling, with a height of no more than 20 centimeters, which, driven by the wind, it is washed inland from the sea, forming what appears to be a small tsunami. Suddenly, in the same way that the event began, the gust of wind stops, leaving a dense layer of fog, which covers several neighborhoods of the city, making visibility difficult.
Since magic does not exist in my story (at least, not that magic), I would not want this phenomenon to happen without a plausible explanation being possible in the real world. One idea I had to explain it was that the energy peak implied the release of heat, with the consequent increase in temperature, causing the evaporation of water. The problem with this is that the releases of large amounts of energy into the sea (for example, a nuclear explosion), at least under normal conditions, do not produce this effect. Another idea I had was a chain reaction, where the spike of energy produced the breaking of the hydrogen bonds of the surrounding water, together with the ignition of the hydrogen. The sudden release and combustion of hydrogen results in an explosion, which apart from breaking a few more hydrogen bonds, boils water, and propagates the steam in the form of shock waves. The second explanation seems to me a little more plausible than the first, but I find some problems with it.
My question, assuming this event isn't too fantastic, is how plausibly could such an event be explained? Alternatively, what changes should I make to make it more plausible?
