Last night my family experienced the biggest earthquake any of us have ever felt. We live in Sitka, Alaska, and we were roused just before midnight by a magnitude-7.5 earthquake just over 100 miles away. I learned how to plot earthquake activity last month, so I thought I’d take a look at last night’s events.

First of all, let’s look at last night’s quake in the context of all the world’s earthquakes over the last 7 days. The following map shows every earthquake that has occurred in the last 7 days, with a magnitude of 1.0 or greater:

On this map, earthquakes of magnitude 5.0 or greater are shown in red. The quake we felt was the large red dot in the eastern Gulf of Alaska. Clearly, it is the biggest earthquake in the world in the last week.

Our son Ever, who is almost two years old, woke up just before the quake hit. I had gone in to see if he needed anything, and when I put my hand on the rail of his crib and leaned over to check on him I suddenly felt dizzy. I thought I had just gotten up too fast, but when I stood up I realized the house was moving! So I scooped him up and stood in the doorway, just as Erin came out to see if we were okay.

We all stood in the doorway for about a minute, and when the shaking was over we took a few minutes to figure out what to do. We pretty quickly grabbed a few things and headed to the local high school, which serves as a tsunami evacuation center. We weren’t sure what to expect as we got in the car. It was surreal, with the tsunami sirens going off and a deep voice booming through the sky saying something like, “A tsunami may be imminent. Go to higher ground. Do not ignore this message.” We felt like they should have just gone ahead and added another line, something like, “You are all going to die. Please do not panic.” People were driving erratically, and I was more scared of getting in a car accident than a tsunami.

We made it to the evacuation center, and waited things out with a bunch of people we know. It was funny to see all the kids in their pajamas, half of them rubbing their eyes looking sleepy, and half of them excited to see everyone at such an unexpected time. We waited anxiously for the first wave to hit, which was scheduled to arrive at 12:43 am. Nothing significant came of it, and we all wondered when we would get to go home. There were reports of aftershocks, and someone reported a 6-inch surge in a town 50 miles south of here.

I was curious about those aftershocks, so I made a plot of just our region. It turns out there were quite a number of aftershocks, and they were not all minor. That one dot on the world map obscures all the aftershocks:

We finally got the all-clear around 3am, and headed home in an uneventful but still slightly eerie atmosphere. Everyone in town seems to have slept in this morning and seems a little more relaxed after our brush with seismic disaster.