When Tuesday night's 4.8 magnitude earthquake hit Vancouver Island and the Lower Mainland, Kent Johansen was working late in his home laboratory in Burnaby.

He heard an alarm go off. An earthquake was coming.

And for a man working with UBC's Earthquake Engineering Research Facility on earthquake detection, that was good news — it meant the system worked.

"I'm thinking, this is serious: this is a real one," he told On The Coast guest host Laura Lynch about the moment he saw the alarm.

"I went upstairs and got my seven-year-old daughter Freya, we got underneath the table in the living room, and I was devastated. I wanted to see all the data roll by!"

Thirteen seconds after Johansen got the warning, the quake hit.

Inside the lab in his Burnaby home, Johansen received a warning about Tuesday night's quake 13 seconds before it hit his home. (Kent Johansen)

Warnings can reduce casualties by half

Alarms powered by the UBC earthquake detectors have been placed in 61 schools on Vancouver Island and the Lower Mainland, and more schools are planned to receive them.

If classes had been in session, students would have heard a loud siren before the quake hit. Schools in Victoria would have gotten about six seconds of warning before the quake hit, and Lower Mainland schools would have received 13 to 16 seconds.

While that might not seem like a lot of time, Johansen said that even a warning of three to four seconds can halve the number of casualties from an earthquake.

Johansen said he is happy with the way the system works, but hopes this quake gets British Columbians thinking about preparing for "the big one" in a more serious way.

"We don't have a lot of the good 'training' earthquakes here in Vancouver, and that's probably why we take the big one that's lurking with such nonchalant distance," he said.

You can see the data the earthquake produced play out as the earthquake happened in the video below.

To hear the full story, click the audio labelled: 13 seconds before last night's quake, quake detectors alerted researcher