How might a volcanic eruption cause both slow changes and rapid changes to landforms?

The diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

Given: circle a externally tangent to circle b. how many possible common tangents to circles a and b can exist? 2 3 4

Which are evidence of the seafloor spreading? a. molten material b. magnetic stripes c. continental material d. drilled core samples e. ocean water samples