Confusing Earthquake Numbers
Lately, we’ve also seen more “surface” events. These are not earthquakes but things like falling rocks, ice breaking off, small landslides, and even strong wind gusts. These can set off our automatic systems, but our experts can tell the difference and don’t include them in the official earthquake list. These surface events are more common right now because of recent warm rain and hot weather. We’re seeing this at other volcanoes too, especially ones with glaciers.
About Our Earthquake Reports
Some people on social media are confused about our earthquake lists and think we report more earthquakes than the USGS. This is not true, in fact the catalog for Washington and Oregon at the USGS is provided by us at PNSN, therefore they are the same! We’re sorry if our blog made things unclear.
Here’s how it works:
We use automatic systems to detect earthquakes. These systems are the same across our whole network and help keep our reports consistent. When the system finds a quake that meets certain quality checks, it gets added to our public catalog quickly. Then, our trained analysts review the data to make sure it’s accurate. These reviewed quakes are shared with the USGS and added to our website. Sometimes the analysts are a few days behind and the official earthquake counts may therefore change for a few days while they process the backlog.
We believe our catalog includes most earthquakes bigger than magnitude 0.8 near Mount Rainier, and most bigger than 1.8 across the Pacific Northwest. Events smaller than that happen but cannot be reliably detected and located with our current methods.
Why You Might See Different Numbers in the Blog
Sometimes we talk about early results from special research projects. These use new tools that can find even smaller earthquakes that the regular system misses. These tiny quakes are usually smaller than magnitude 0.8, and some are even smaller than 0.0! That just means they’re very, very small.
We expect to find maybe 10x more tiny quakes using these new tools. But don’t worry—this doesn’t change the big picture. It just helps us see more details.
Why This Matters
By studying these small quakes, we can learn more about how the earthquake swarm is happening and what faults are moving underground. Two research projects are working on this right now.
Usually, scientists wait to share results until they’ve been carefully checked and published in science journals. But we think it’s important to show you what we’re working on and how science helps us understand nature. We’ll keep updating this blog with new info as we learn more!