What Does Earthquake Magnitude Really Mean?

With two massive earthquakes striking Mexico, less than two weeks apart – one at a 7.1 and one at an 8.1 magnitude – it’s important to understand how seismologist weigh the size of a quake.

According to today’s science, the magnitude of a temblor is determined by the amount of energy released by the shaking.

For an earthquake to go up one whole magnitude, that means the strength of the quake increased by 32 times.

This would mean that a 5 magnitude earthquake is 32 times greater than a 4 magnitude earthquake and that an 8 magnitude earthquake is 1,000 times greater than a 6 magnitude earthquake.

These calculations matter a great deal, especially when examining the difference between the 8.2 earthquake seismologists predict will hit the San Andreas fault (which runs through Los Angeles), in comparison to the 6.7 earthquake that devastated Northridge in 1994.

Magnitude especially matters when talking about active earthquake areas near densely populated regions. That’s why Mexico’s 8.1 earthquake was far less deadly than the 7.1 magnitude earthquake that hit just outside of their capital, Mexico City.

Any earthquake over a 6 magnitude raises concerns. It’s these types of tremors that can damage buildings and move furniture, especially in non-retrofitted structures. While a size 7 magnitude earthquake or greater can throw furniture and inflict damage to the newest of structures.

Also this week, Japan experienced 6.1 earthquake 185 miles from Ishinomaki and New Zealand had a 6.1 earthquake 381 miles from Invercargill.

Now, more than ever, it’s important to be proactive about earthquake preparation and safety.

Julian De La Torre is an expert in Los Angeles foundation inspection, foundation contractors and foundation repair. Julian’s company, Julian Construction, has inspected over 15,000 structures, working with engineering firms and local departments of building & safety. The company has done more foundation repair in Los Angeles than any other company in the area over the last five years.