Because of the barrier of ice to the east, the Pacific Ocean to the west, and populated areas to the north, there may have been a greater impetus for people to move in a southerly direction.
Rested in the Pacific Ocean, Mauna Kea's peak rises above the bulk of our planet's dense atmosphere, where conditions allow telescopes to obtain images of unsurpassed clarity.
Changing weather patterns may also put densely populated areas at risk of deadly flooding, along with the resulting contamination of food and water supplies.
It is a shocking event that reminds people of some more basic risks that may threaten the economies of the densely-populated and seismically vulnerable Japanese archipelago.
Although the large ash plume was not unparalleled in its abundance, its location was particularly noticeable because it drifted across such well populated areas.
Computer simulations of this impact show that both of the objects would melt in the impact and the dense core of the impactor would fall as molten rock into the liquefied iron core of Earth.