If a substantial amount of calcium is discovered, coronary artery disease may be likely. A CT coronary angiogram, in which you receive a contrast dye injected intravenously during a CT scan, also can generate images of your heart arteries.
At converging plate boundaries, two situations are possible. First, both volcanoes and earthquakes form where one plate sinks under the other. This process, called subduction, takes place because one plate is denser than the other. The denser plate, which invariably has oceanic crust on its top, does the sinking. Second, only earthquakes occur when two plates collide (obduct), building a mountain range.
Volcanic activity. Where tectonic plates meet, the Earthâs crust becomes unstable as the plates slide past each other, push against each other, or ride under or over one another. Earthquakes and volcanic eruptions happen at the boundaries between plates. Magma (molten rock) is less dense than the crust. It can rise to the surface through weaknesses in the crust, forming a volcano. Geologists study volcanoes to try to predict future eruptions. Volcanoes can be very destructive, but some people choose to live near them because volcanic soil is very fertile. Earthquakes