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.
The greatest number of the Earth's volcanoes occur on the ocean floor. ROV Jason gets a close view of magma explosions and lava flows on West Mata volcano. Volcanic eruptions occur only in certain places and do not occur randomly.This is because the Earthâs crust is broken into a series of slabs known as tectonic plates. These plates are rigid, but they âfloatâ on a hotter, softer layer in the Earth's interior.lthough most of the active volcanoes we see on land occur where plates collide, the greatest number of the Earth's volcanoes are hidden from view, occurring on the ocean floor along spreading ridges.