On the Potentially Hazardous Asteroids: Origin and Tsunami Phenomenon

Recently some small celestial bodies have approached to the Earth. Asteroids with this characteristic are wellknown as Near Earth Asteroid (abbreviated as NEA). These asteroids are divided into three classes: Aten, Apollo and Amor (AAA) types. At present time more than 35000 orbital elements of NEA have been already determined. Many of them have the orbit overlapping with that of the Earth in the region of perihelion. NEA is widely believed to be continuously injected into Earth-approaching orbits from main-belt asteroids occur as consequence of energetic interasteroidal collisions. If these asteroids cross the Moon’s orbit it is more possible theycrash in to the Earth. The asteroid with this criterion named Potentially Hazardous Asteroid (PHA). The hazards of collisions with the Earth somewhat in exaggeration and the news made a little panic in the community. On these small bodies, the future positions can be calculated to a certain extent from the orbital elements. However, more dangerous are unknown, small bodies approach to the Earth without any previous notice, and the number of these unknown Earth approaching small bodies with diameter larger than 0,5 km is estimated amount to nearly 10,000. The hazards of asteroid or comet collisions are direct ones and indirect (afterward) ones. The direct hazards are a huge earthquake, a tsunami and an urban and wild fire. The indirect hazards are the large temperature drop, acid rain fall, and depletion of ozone layer. These direct hazards are local a short term, but the indirect hazards will be world wide and long duration. The worldwide temperature drop that has serious effect on photosynthesis is most important to a crop production and in turn to surviving of human being. This paper present the direct hazards in case asteroid fall into the ocean and discuss some empirical formulas about the effect of asteroid collision to the Eart