The deadly 6.5-magnitude earthquake that has killed at least 398 people and toppled more than 10,000 homes in Yunnan province was the largest quake the province has suffered in the past?18 years.

Even so, the tragic human cost was disproportionately large.

For example, 16 people died in a 6.2-magnitude quake in Dayao, Yunnan province, in 2003. The next year, in a 5.6- magnitude quake in Ludian — the same area that was hit on Sunday — four people died and 594 people were injured.

Simply comparing death tolls and magnitudes does not explain the substantial differences between the most recent earthquakes in Yunnan.

For Sunday’s quake, for example, the magnitude may not appear very high. Yet as local seismic officials explained, it was a shallow quake which is usually more destructive than deep-focus quakes. The focus of the quake was only 12 kilometers underground.

Another contributing factor to the heavy casualties was the high population density of the victimized area. The density of the population in the central quake-affected area is 265 people per square kilometer while the provincial average is 110 people.

Those factors certainly contributed to the serious loss of lives. Still, the world must wait for a formal investigation to know exactly what the real causes were.

Although it will take some time for us to know the truth, the catastrophe can still offer us some clues as to how we can minimize losses during unpredictable quakes.

Video clips show that most of the toppled homes were obviously built by local farmers using bricks and wood, which can hardly meet national construction standards.

As China’s economic strength improves, farmers in many parts of the countryside can now afford well-built homes. They can now afford to hire professional teams to build their homes. Still, many do not.

In areas where earthquakes are frequent, low construction standards can cost lives.

Authorities, therefore, must draw lessons from the Ludian quake in Yunnan and promptly assess how many people in the country’s seismically active areas still live in vulnerable homes.

Based on the assessment report, the central and local authorities should make thorough plans to help people rebuild their homes to resist serious quakes.

Earthquakes are unpredictable. It is almost impossible to prevent them from causing damage or casualties. Good preparations, however, will help reduce the harm.

Let’s start by reinforcing or rebuilding all fragile homes in earthquake zones.