Earthquake in the Philippines, June 8th 2026. A soft story story.

The 7.8 Mw earthquake just south of the Philippines island of Mindanao was not exactly unexpected. The region is tectonically active and has seen many historic earthquakes. An earthquake with magnitude Mw 7.8 is not huge and doesn't qualify for the terminology of the science to be described as a Great earthquake. In the the map below the recent earthquake is shown with a yellow star embedded in a background of hundreds of historic eartquakes identified by circles of different size and hue indicating their magnitude and depth. The Map is from the USGS.

At least 35 people died and more than 200 injured. That is, in fact, not an extremely large number of fatalities for an earthquake of that magnitude in a densely populated region. The population dnsity in the region is over 370 people per square kilometer, more than six times the world average of 61.

Many of the images of destruction like that above show the same features. Technically this is known as "soft story collapse" and occures when a building structure is supported by relatively thin columns that create open space that is often used for parking or businesses. There are often residences above. The graphic below shows the idea.

It shows a two story residential structure atop weak columns that have failed during earthquake shaking. Although it is a sketch it quite accuratly describes the cause of the damage seen in the image of the Philippines earthquake. And below an image of cars squashed beneath a collapsed buiding in California following the Northridge earthquake

So, the soft story collapse is not unique to developing countries.

Buildings can be retrofit to reduce the possibility of soft story collapse. It basically involves strengthening the lower, soft story which might include replacing the columns that support the upper stories with much stronger structures.

While these measures are entirely plausible and require no sophisticated engineering skills they may not be affordable in many developing country settings. Most important is not to permit construction of this type of building.