We have been trying to discover the answer to this question for a long time. Wonderful Researchers Dear Wonderful Researchers, You guys are very perceptive to realize that volcanoes change over time. A dramatic example is the evolution of Hawaiian volcanoes. Then they keep stacking lava flows another couple miles. They might form, fill, and reform calderas many times.
Most Hawaiian volcanoes spread sideways under their own great weight.
Many of them even fall apart in giant landslides. Ultimately, as they move off the hot spot, they stop erupting and slowly sink below sea level. The structure of stratovolcanoes, like Shasta and Hood, can change over time. Large landslide have removed big pieces of both of these volcanoes. Changes in the structure of the volcano are important.