Why Can’t We Predict When a Volcano Will Stop Erupting?

On September 19, Cumbre Vieja—a volcanic ridge covered in the rocky scars of past paroxysms—erupted for the first time in 50 years. Every single day thereafter, molten rock cooking at nearly 2,000 degrees Fahrenheit has poured from multiple fissures and vents, frequently accompanied by explosions propelling glassy ash…