Mexico faces earthquakes, floods, tsunamis, and hurricanes.
Answer:
A hydrometer is a instrument used to determine specific gravity. It operates based on the Archimedes principle that a solid body displaces it's own weight within a liquid in which it floats. Hydrometers can be divided into two general classes: liquids heavier than water and liquids lighter than water
If you're referring to streams/rivers of water that run independently of another source in the ocean these are referred to as "currents" and can be very powerful depending on their location.