Volcano Watch: How do lava flows cool and how long does it take?

This aa flow erupted from fissure 8 on Kilauea Volcano’s lower East Rift Zone on June 1, shows how the interior of a lava flow remains incandescently hot even though surface cooling forms a crust of solid rubble. Based on studies of lava flow cooling rates, it will take more than 130 days for a flow this thick (about 15 feet) to cool to a temperature of about 200 degrees Celsius (290 degrees Fahrenheit). (USGS photo courtesy / A. Lerner)

Since the end of the 2018 lower East Rift Zone (LERZ) eruption on Kilauea Volcano, questions have surfaced concerning how long it will take for the new lava flows to solidify. This is a difficult question to answer, because the initial eruptive temperatures along with many different factors can influence the rate of cooling.