The Brief California Tsunami Warning Holds Important Lessons

From a vital little buoy to an epic fail on Musk's X, some things to ponder after the 7.0 seabed earthquake.

The 7.0-magnitude submarine earthquake that startled Northern Californians on Thursday morming and generated a quickly withdrawn tsunami warning is a reminder of a mega-threat millions of people in the United States and tens of millions more around the world face.

Much of the modern world was built in a gap between far more powerful earthquakes, as my #MindTheGap disaster-awareness cards note:

That makes it easy to lapse into somnolent “whatever” mode and focus on the inconvenience of a tsunami warning that didn’t pan out.

The initial 7.3-magnitude quake assesssement and warning were quite stark, leading to a bit of public whiplash when the warning was canceled about 50 minutes later.

The New York Times ran a story on San Francisco reactions with this subheading: “Many Bay Area residents raced away from the ocean after a jolting cellphone alert warned, ‘You are in danger.’ Others raced toward it.”

That is the human way….

Disaster warnings in situations where data are initially scant are a tough judgment call and must be accompanied by a lot of pre-disaster education (like the annual earthquake “Great Shakeout” exercise). The ground motion is only one factor determining if a seafloor jolt generates dangerous waves.

Insert, Dec. 7, 7:45 a.m. ET - I reached out to veteran University of Colorado earthquake researcher Roger Bilham and others and Bilham sent this note from the field, where he is out collecting data along the San Andreas Fault (I cleaned up some typos): “The Mendocino fracture zone can’t generate tsunami. I was surprised to see any kind of alert. It is a strike slip fault on flat (ish) sea floor- the sliding doesn't push water around.”

The Substacking earthquake researchers

Judith Hubbard & Kyle Bradley

posted a helpful explainer noting that there was a significant possibility of a tsunami nonetheless, and that justified the warning:

Because the earthquake was strike-slip, causing lateral rather than vertical motion of the seafloor, it was not expected to trigger a tsunami. However, it is always better to be safe than sorry: even strike-slip earthquakes can cause underwater landslides, which can create tsunamis. Because underwater landslides are difficult to detect (much more difficult than earthquakes), the only way to be sure this did not happen is to wait and see. - end of insert

Times reporter Camille Baker filed a helpful short explainer on the assessment and decision process delineating which type of alert is issued.

The tsunami of confusion on Elon Musk’s X

Twitter, which had become a mainstay for disaster-warning communication, utterly failed as X, thanks to a host of changes mandated by Elon Musk, as Times reporter Ryan Mac explained in an X thread (and on Bluesky):

The tsunami scare today in the Bay Area illustrates how Elon Musk has changed X for the worse in emergencies. This is the real account of Berkeley PD. But changes in verification means it no longer has a verified badge. Anyone searching for immediate info might be uncertain if this post is legit.

The link in the post meant it did not get as much play by the X algorithm. And not having a verified badge meant other content was prioritized over it as well. Now some users are seeing that X is removing exact time stamps from posts. That will only lead to more confusion in emergencies.

Public service accounts were so crucial to Twitter and Musk undermined them almost immediately after his takeover. Twitter employees warned him when he wanted to change verification.

Ryan Mac is the co-author, with Times tech reporter Kate Conger, of an essential book on Musk and Twitter, Character Limit (one of the best double entendres ever?) and I’m working with them to join a Sustain What webcast soon.

I hate to say I told you so, but I did write this piece two years ago drawing on the wisdom of a former disaster-comms-focused Twitter engineer, Jim Moffitt, and

Samantha Montano

, among others:

A monitored Earth is a safer Earth - all hail DART buoys

I’ll close by circling back to the tsunami warning itself. One thing to note about the warning: it came because of substantial - but still insufficient - investment in realtime monitoring of Earth systems that can threaten human affairs in big, if rare, ways.

The little red squiggle in this image below is the signature of the earthquake detected by and transmitted from one of the buoys in the DART earthquake and tsunami monitoring network established across the Pacific and Indian Oceans (and some other water bodies) in recent decades. [Insert, Dec. 7, 7:30 a.m. ET: Just to be clear, the squiggle was not a passing tsunami; it’s the record of what’s called a Rayleigh wave passing in the seabed.]

Here’s a wider view.

This system is getting old and outdated and it’s worth crediting the outgoing Biden administration for devoting $30 million from the Bipartisan Infrastrucuture Law to beef it up. Incidentally, the buoy in the photo is the one in Mendocino Bay that generated that vital signal.

Somehow I don’t think you’ll be seeing that kind of long-term investment in resilience coming under the incoming Trump administration with its DOGE advisors including Elon Musk, and with NOAA already a stated target of Project 2025. I’ll be eager to credit them all if they do the right thing.

Coda

I’m best know for my 40 years on the climate beat, but I’d like to think my earthquake risk reporting has been as helpful to society.

In December 2004 I was the lead writer on a New York Times deep dive into the science pointing to under-appreciated tsunami threats, focused on the Boxing Day catastrophe as the tsunami pulse from an Indonesian mega quake exacted horrific tolls across the Indian Ocean. Before and after that event, I’d written about vastly increased exposure to such danger, particularly in the Pacific Northwest, where the “mind the gap” warnings are particularly clear.

I’ll be keeping at this with your help, so please support what I’m tring to do financially if you can.

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