This tragic earthquake was not the strongest, but was certainly the deadliest earthquake in history: ~ 830,000 killed. Most of the victims were in their homes that were carved out of the loess covered hillside. The soft soil made caves practical homes for many, but they collapsed easily during the shaking.

Shaanxi, China

Explanation:

Earthquakes occurred in the china known as the deadliest earthquakes in the record of human history and about 830,000 people lost their lives occurred in 23 Jan 1556, more than 97 provinces were affected.  An area of 840 km was destroyed and most of the population living in artificial caves in loess cliffs were entirely collapsed causing many casualties. The epicenter as located around the Wei River valley and in places 20 meters deep crevices were created. The earth had a magnitude of 8.1 on the Richter scale.

The geographic feature in the westernmost corner of kenya is answer: the great rift vally