The report outlines how when a nuclear weapon goes off underwater, it produces a cavity of hot gasses, which then collapses. If the explosion happens near the surface, it can create some pretty big waves—under some circumstances, they can be hundreds of feet high near ground zero.
Tsar Bomba was the Western nickname for the Soviet RDS-220 hydrogen bomb the most powerful nuclear weapon ever detonated. Its test on October 30, 1961 remains the most powerful human-made explosion in history. Developed by the Soviet Union, the bomb had a yield of 57 megaton TNT (210 PJ). In theory, the bomb had a maximum yield of 100 megatons if it were to have included a U-238 tamper, but because only one bomb was built, this was never demonstrated. The fireball reached nearly as high as the altitude of the release plane and was visible at almost 1,000 km (620 mi) away from where it ascended. The mushroom cloud was about 64 km (40 mi) high (over seven times the height of Mount Everest), which meant that the cloud was above the stratosphere and well inside the mesosphere when it peaked. The cap of the mushroom cloud had a peak width of 95 km (59 mi) and its base was 40 km (25 mi) wide.
All buildings in the village of Severny (both wooden and brick), located 55 km (34 mi) from ground zero within the Sukhoy Nos test range, were destroyed. In districts hundreds of kilometers from ground zero wooden houses were destroyed, stone ones lost their roofs, windows and doors, and radio communications were interrupted for almost one hour. One participant in the test saw a bright flash through dark goggles and felt the effects of a thermal pulse even at a distance of 270 kilometers (170 mi). The heat from the explosion could have caused third-degree burns 100 km (62 mi) away from ground zero. A shock wave was observed in the air at Dikson settlement 700 km (430 mi) away; windowpanes were partially broken to distances of 900 kilometers (560 mi). Atmospheric focusing caused blast damage at even greater distances, breaking windows in Norway and Finland. Despite being detonated 4.2 km above ground, its seismic body wave magnitude was estimated at 5–5.25. Sensors continued to identify the shockwaves after their third trip around the world.
The US 15 megaton Castle Bravo bomb formed a fireball almost 4.5 miles (7.2 km) across within a second. The explosion left a crater 6,500 feet (2,000 m) in diameter and 250 feet (76 m) in depth. This would be about 300 million tons of displaced dirt.
A 100 megaton bomb would be a modification of the 1961 USSR capability with Tsar Bomba. It would have almost 7 times the power of the Castle Bravo bomb. If the displacement scaled with the power, then it could displace 2 billion tons of water.
On July 9, 1958, an earthquake shook 90 million tons of rock into Alaska's isolated Lituya Bay; this created an astounding 1,724-foot-high wave, the largest ever recorded. A 2010 model examined the amount of infill on the floor of the bay, which was many times larger than that of the rockfall alone, and also the energy and height of the waves, and the accounts given by eyewitnesses, concluded that there had been a "dual slide" involving a rockfall, which also triggered a release of 5 to 10 times its volume of sediment trapped by the adjacent Lituya Glacier, as an almost immediate and many times larger second slide, a ratio comparable with other events where this "dual slide" effect is known to have happened.
In 1792, part of Japan's Mount Unzen collapsed, hitting a series of nearby bays with waves as high as 300 feet, and killing some 15,000 people.
It’s all about energy. Frequency and Amplitude (shape of ocean floor, shoreline and up-slope factors). It is conceivable that some tsunamis will rear up quickly (and very high) once they reach the shore (depending on the shape of the ocean floor leading to the shore), and then ‘break’ and lose much of its energy in a relatively short distance.
CITY, (Current elevation above sea level, feet)
Portland, ME (~ 50′)
Boston, MA (~ 30′)
New Haven, CT (~ 50′)
Bridgeport, CT (~ 40′)
New York City, NY (~ 20′)
Jersey City, NJ (~ 30′)
Newark, NJ (~ 50′)
Atlantic City, NJ (~ 10′)
Wilmington, DE (~ 80′)
Philadelphia, PA (~ 40′)
Virginia Beach, VA (~ 10′)
Wilmington, NC (~ 20′)
Myrtle Beach, SC (~ 20′)
Charleston, SC (~ 10′)
Savannah, GA (~ 10′)
Daytona Beach, FL (less than 10′)
West Palm Beach, FL (less than 10′)
Fort Lauderdale, FL (less than 10′)
Miami, FL (less than 10′)
SOURCES- wikipedia, Modern Survival Blog, Youtube (BBC)