How have volcanism and thermal expansion both shaped the Ethiopian Plateau?

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plateau The Columbia Plateau is uniformly covered with basaltic lava flows and spans an area of about 100,000 square miles in Idaho, Washington, and Oregon.

The Ethiopian Plateau was primarily shaped by the thermal expansion of the underlying lithosphere. When hot material from the asthenosphere upwells, it heats the mantle, causing the surface to rise to a high, relatively uniform elevation.1

While thermal expansion is the primary driver of the plateau's high elevation, volcanism has also played a significant role. Cenozoic volcanic rocks cover much of the plateau, particularly in its flattest areas, effectively burying the preexisting terrain. Because these two processes often occur simultaneously when the upper mantle is exceptionally hot, they have worked in tandem to define the plateau's current structure and topography.1