Because the. plates grind together
Their homes will likely be crushed by another lahar.These dangers incorporate surges, lahars, avalanches, pyroclastic streams, magma streams, and tephra aftermath. These perils can devastate a region as well as impact water quality and other wellbeing dangers in spots that survive. Some of Mount Rainier's risks are not related with an ejection.
Answer:
B and C
Explanation:
B. In a given rock sample, the amount of Silicon-32 isotopes gets divided in half about every 170yrs.
This is the concept of half-life. Half life is the time take for half of a radioactive isotope to disintegrate. The shorter the half life the faster the isotope disintegrates.
From the question, we were told that it would take 170yrs for half of the isotope of Silicon to disintegrate to Phosphorus. This is the half life.
C. The half life can be used to determine the amount of Si-32 that has decayed from the time closure temperature was reached.
The closure temperature is very important in radioactivity. It is the temperature at which a system has cooled and there is no resulting disintegration of parent and daughter isotopes.
From first order kinetics, we know that the rate at which radioactive elements decay at any time is directly proportional to the number of radioactive atoms present. A knowledge of the half life helps to figure out the number of atoms that has decayed in time.
If we have the intersection of the equator and the prime meridian as a starting point, and we move towards west, than the three oceans that we will encounter will be in the next order:
1. Atlantic Ocean; lies between Europe and Africa from one side (eastern borders), and North and South America on the other side (western borders). It is in fact our starting point.
2. Pacific Ocean; lies between Asia and Australia form one side (western borders), and North and South America from the other side (eastern borders).
3. Indian Ocean; lies between Southeast Asia and Australia (as its eastern borders) and Africa as its western border, and on the north it borders with South Asia.
The northernmost ocean on our planet is the Arctic Ocean, which is lying around the Arctic circle.
The southernmost ocean is the Southern Ocean which surrounds Antarctica with its waters.
