question:  What was the second phase of the natural disaster?
context: It has happened a hundred times in the long history of Earth—and, sooner or later, will happen again! It was still a matter of academic interest when in the late '40s geologists speculated on the relationship between the Kiowa Fault and the Conchas Fault farther south, in New Mexico, and which followed the Pecos as far south as Texas. Nor was there much in the papers a few years later when it was suggested that the Niobrara Fault (just inside and roughly parallel to the eastern border of Wyoming) was a northerly extension of the Kiowa. By the mid sixties it was definitely established that the three Faults were in fact a single line of fissure in the essential rock, stretching almost from the Canadian border well south of the New Mexico-Texas line. Only Joseph Schwartzberg, head geographer of the Department of the Interior, wondered if the disturbance might not be a settling of the Kiowa Fault. The idea was not nearly so exciting as a volcano, even a lava-less one, and you couldn't draw a very dramatic picture of it. The dust volcano was on the face of it a more plausible theory. As the tremors grew bigger, along with the affected area, as several towns including Edison were shaken to pieces by incredible earthquakes, whole bus- and plane-loads of geologists set out for Colorado, without even waiting for their university and government department to approve budgets. They found themselves on the scene of what was fast becoming the most violent and widespread earthquake North America—probably the world—has ever seen in historic times. To describe it in the simplest terms, land east of the Fault was settling, and at a precipitous rate. East, where sharp reports and muffled wheezes told of continued buckling and dropping, the earth trembled downward. By 16 September the landslip had crept down the Huerfano River past Cedarwood. The Platte River, now, was creating a vast mud puddle where the town of Orchard had been. As the Fault moved north and south, new areas quivered into unwelcome life.
output:  The falling rock that was giving way.
options:  The falling rock that was giving way.  The dust clouds that were taking over.  The flock of refugees seeking safety.  Annoyingly loud noises that halted progress on rebuilding.