After studying the graph you posted and doing some research there are several tectonic features beneath the moving Pacific Plate that caused the volcanoes to form in both the Loa and Kea trends. A few of the acceptable answers are rising magma, Hawaii Hot Spot, mantle plume, and a hot spot.
"<span>Rust Belt" is a term for upper Northeastern United States region and other like the Great Lakes, and the Midwest States, referring to economic
decline, population loss, and urban decay due to the shrinking
of its once powerful industrial sector.</span>
I think the best characteristic that is common among the Greek city allow them to be pulled together in one city are letters A. worship of the same gods and B. common language. I hope you are satisfied with my answer and feel free to ask for more