Archive for the ‘Earthquakes’ Category

What name shall we give Earthquake?

12 December 2022

I think about earthquakes nearly every day, in one aspect or another. Every now and then I toy with the pre-scientific ideas about them. Before science, before literacy itself, every culture stored knowledge about the world in the form of images and especially in stories, told and sung, that were passed down the generations. Natural events were commonly assigned to the interactions of specific beings, with names and personalities, giving a relatable gloss to earthquakes, eruptions, meteorological phenomena and other doings that science reliably informs us are actually random.

Maybe you’ve heard of the oral traditions of the Pacific Northwest tribes, who remembered the great Cascadia earthquake and tsunami of 26 January 1700 in stories for more than two centuries. Many versions recounted the event as a great clash between Thunderbird, ruler of the wind and sky, and a sea creature referred to by convention as Whale. The same two entities populate the tribes’ art in a motif that informs their most deep-seated culture. And it all connects with the ordinary occurrence, seen every day along that coast, of eagles catching fish. Earthquakes and tsunamis come with the country and have seats around the evening fire.

In Japan there is the character of Namazu, a great catfish who lives restrained deep underground. Every now and then it thrashes loose, upending society with destructive shaking and floods from the sea. According to one authority, Namazu originated around the sixteenth century from “the Chinese ao, a hybrid fish/turtle/dragon.”

Namazu got a big boost with the Ansei Edo earthquake of 11 November 1855, the third of three catastrophic quakes in central Japan in 1854-1855. In Edo (modern-day Tokyo), the worst damage was in the wealthy quarter, and after a few weeks of aftershocks and widespread fear the city’s mood lightened as money flowed to pay for rebuilding. Widespread cartoon leaflets from the time record the changing attitudes in the form of catfish imagery.


The earthquake, personified as the catfish Namazu, forces money from wealthy property owners. Wikimedia image

That catfish, the Big One, is still around, ready to thrash and ready to hand when the Japanese need a symbol. A stylized Namazu is part of the national earthquake warning system‘s iconography.

Source

In the mythology of ancient Greece, Poseidon the earth-shaker rules both the sea and earthquakes. So does his ancient Roman version, Neptune. Both personages embody the connection between earthquakes and tsunamis.

The U.S. Geological Survey has a small collection of earthquake legends from these and other cultures.

These ancient personifications all share the same feature: they present Earth forces as animate, as beings. The geologist’s Earth is also an active one, but we have always regarded it as, in Hutton’s 1785 phrase, “a machine of a peculiar construction.” It doesn’t have a soul. The geologist’s Earth is an engineering conception — the more science can understand this version of Earth, the better our engineering will be. It’s wonderful for what it makes possible, but not the first and last word.

The beauty of the animal personification is that an animal is an integral being, connected within itself. These days it would pay off, I sometimes think, to bring the Earth and its attributes back into the family. I suggest that we could use personifications today — not seriously, but ceremonially.

I suggest that we think of the half-forgotten Makkeweks, a sea being like Poseidon and Namaku and Whale, as our local earthquake avatar. We have a single story, from the Rumsen Ohlones of the far South Bay, that refers to this being. Coyote came to the shore with his wife, having instructed her about the various sea creatures — sea lions, sharks and so forth — and told her not to fear them, as they are our uncles. But he didn’t tell her about Makkeweks, and when Makkeweks showed up she was frightened to death, whereupon Coyote had to revive her.

It’s reasonable that our local Ohlone tribes, of the Huichin community, shared a story much like this, perhaps with the same names. And so it’s fitting that the city of Oakland has commissioned and placed a bronze statue of Makkeweks in Snow Park, down by the lake.

Maybe somehow we could recognize that Makkeweks, the Big One, is our uncle, part of the family, an actor in the world who belongs among us and for whom we must always make room in our lives.

Stop saying “overdue”

25 October 2021

The last week has had its share of local earthquake news, even though there weren’t any earthquakes nearby. It all centered around the release of volume 3, the last part, of the massive HayWired Scenario report, conveniently timed for 21 October, anniversary of the 1868 Hayward earthquake (not to be confused with the 17 October earthquake of 1989).

HayWired is a virtual magnitude-7 earthquake, complete with aftershocks, that represents a typical Big One on the Hayward fault. Seismologists created it as accurately as their science permits, then asked emergency responders, social scientists, planning agencies, structural engineers and other specialists what they think would happen to the Bay area and how they would handle it. Volume 3, “Societal Consequences,” presents all their answers, as accurate as their expertise permits.

In brief, the consequences would be dreadful. Ace reporter Ron Lin of the Los Angeles Times wrote an able summary that I’ll just point you to rather than write my own. Besides, I covered some of the same ground a few months ago.

The East Bay Times, to its credit, also ran Lin’s story, and two days later it issued a wake-up editorial, “Prepare today for next major Bay Area earthquake,” aimed at goosing its readers into action against the threat. It’s a bit overdone, starting with the opening paragraph: “Gulp.” I don’t really mind that, but the editors went on to say something sloppy that I will focus on today:

“We know that the last major earthquake on the Hayward Fault occurred in 1868 — 153 years ago. We also know that, on average, dating back to the year 1134, the fault produces a major earthquake roughly every 150 years. So, yes, we’re overdue.”

No, we are not overdue. Scientists don’t use that word because it’s a deep error in thinking. Something that’s overdue is late, behind schedule, and earthquakes don’t follow a schedule. I don’t like scaring people with inaccurate statements.

Ron Lin, to his credit, stopped short of using the O-word:

“The Hayward fault is one of California’s fastest moving, and on average, it produces a major earthquake about once every 150 to 160 years, give or take seven or eight decades. It has been 153 years since the last major quake — a magnitude 6.8 — on the Hayward fault.”

Instead, he included the uncertainty around that irresistibly tempting “average.” That was helpful, but he didn’t come up with the best word.

Even the U.S. Geological Survey creeps close to the wrong word in its excellent Fact Sheet 2018-3052 titled “The Hayward fault — Is it due for a repeat of the powerful 1868 earthquake?” It sidles up to this D-word, and by implication the O-word, by saying that “the interval between successive quakes has varied from 95 to 183 years, averaging 150 years, and it is now more than 150 years since the 1868 earthquake….” and trails off with that coy string of dots. The sentence leads with the uncertainty, which is good, but the conclusion it implies is not correct. The graphic it goes with is useful in showing the raw numbers behind the average:

There’s a rhythm to this timeline, but not a good beat. Here’s a longer timeline, currently the best we have, that presents the uncertainty of the radiocarbon-based dates in it:


Source: USGS

Those snappy stars are actually smeared into blurs. For instance, the date of that event “in the year 1134” that the newspaper cited is uncertain by over a hundred years.

Maybe I’ve made it clearer what frosts me (and most seismologists) about the O-word. Now the correct, best word for the situation on the Hayward fault is this: the fault is ready for a major earthquake. It’s primed, loaded, set to go. This is scientifically correct because we’ve measured the actual motions of the crust around the fault and know that since 1868 it has accumulated enough strain energy (the kind in a stretched rubber band) to be released in a HayWired-sized earthquake. “Ready” is not as scary as “overdue,” but sit with it and the word is pretty motivating just the same. Are YOU ready?

The prospect of reading the whole HayWired Scenario report is intimidating. I recommend Chapter R as a good summary that will guide you to specific chapters where you can dive deeper.

The HayWired scenario of lost homes

5 July 2021


Soft-story damage in San Francisco’s Marina district, 1989. Retrofit programs in Oakland aim at preventing this kind of destruction.

As you all know, the Hayward fault runs through the middle of Oakland and the whole East Bay, and as you all know it will rupture some day in a large, destructive earthquake — a catastrophe on the scale of the 1906 San Francisco quake and fire, or Hurricane Katrina in New Orleans in 2005.

A large group of researchers led by the U.S. Geological Survey has been working with governments, insurers and others on ways to foresee what the earthquake will do, in hopes we can counteract the worst of it beforehand and cope better with it afterward. Their product is a detailed earthquake scenario, called HayWired, that enables planners of all kinds to work together in a coordinated way and come up with meaningful, actionable recommendations. I’ve been following the effort, and reporting on it here, for four years now.

Last week I checked in on the state of the effort in an online seminar by SPUR, the regional planning nonprofit, titled “Where Is Home after a Large Earthquake in the Bay Area?” (This and previous seminars can be found here.) Prompted by the release of new chapters in volume 3 of the HayWired report, it focused on rebuilding housing after the HayWired quake in the communities most at risk. Forgive the metaphor, but we have to light a fire under all levels of government and keep blowing on it.

The HayWired scenario earthquake is a magnitude-7 event that occurs on an April morning, rupturing the whole northern half of the fault from an initiation point under the Crestmont neighborhood. As the shaking ends, landslides grind their way down hundreds of hillsides, bayside ground turns to soup and almost 500 large fires are triggered. Some 800 people are dead, not counting deaths related to the fires. In the nine-county Bay area, a million buildings are damaged or destroyed. Property losses amount to $40 billion in Alameda County alone. These are the best estimates we know how to make.

That’s all before we get to the local impacts. A belt of badly damaged neighborhoods extends along the fault from Pinole to Fremont plus outliers in Novato, Pleasanton and Vallejo, but the community most at risk is all of East Oakland.

Even when the houses survive, neighborhoods don’t just heal. People will keep leaving heavily damaged areas, in “voluntary displacement,” for three understandable reasons:

1. They can’t afford to stay — their jobs fail, their money runs out, rents rise too high.

2. They can’t stand to stay — roads and transit and water are down for months and perhaps longer; schools and shelters shut down; aftershocks drive them nuts.

3. They don’t have to stay — they’re young, they’re mobile, they’re ready to go somewhere better.

Voluntary displacement was a notable factor after the 1994 Northridge earthquake, when neighborhoods turned into “ghost towns” as people kept moving out, especially where multifamily residences were common. In New Orleans it was even worse. And it will be a big consideration in East Oakland, where so many residents already have “vulnerability factors” like low income, language problems, youth and old age, and lack of education.

I’m almost done with the bad news. Government money will be slow in coming and far short of the need. Earthquake insurance will help individuals who can afford it, but no one will be made whole. And some areas will require a complete makeover, which will take years of planning and be politically fraught.

What can be done to help in advance? We have shoestrings of help like the state government’s earthquake insurance fund. We have the state’s Earthquake Brace + Bolt program that helped pay to strengthen 15,000 dwellings. (Until they announce more funding for 2021 especially for underserved neighborhoods, you can find qualified contractors on their website.) Oakland has a slow-moving mandatory retrofit project aimed at saving our existing housing stock from collapse. Those small-scale programs are laudable, but they won’t cut it.

Speakers at the seminar pointed to larger efforts. On the biggest scale, SPUR issued a report this year on fixing the Bay area’s massive housing problem over the next 50 years. Every new house or apartment is more earthquake-resistant than anything older, which is why I strongly favor housing construction at all scales. I learned the most from Maziar Movassaghi of the state Department of Housing and Community Development, who had hard-won advice from the 2018 Camp Fire disaster. Recovery has taken years because people couldn’t build new multifamily housing until the roads and infrastructure were ready, and then the financing took even longer. The bureaucracy is complicated, the money is tight and it all takes too long for people to endure. And all the while the pressure is to do the easiest thing — build back what used to be there — rather than the resilient thing — build something better.

What Movassaghi recommended was to have plans in place for housing recovery after disasters, the lack of which was a big obstacle after the fires. (He noted a good example from San Jose.) Funding agencies won’t just write a big check — a multiyear community development block grant — if your city can’t show them it knows what it’s doing. Such plans, he said, should be made jointly by community-development folks and emergency-management folks, to make sure the new neighborhood will come through the next disaster better than it did this one. Having good plans in place can save your city years of misery.

For most of us this kind of work is above our pay grade, but it’s within our horizon of concern. We can do what citizens do: listen, learn and lobby our public servants.

Previous posts:

HayWired, an imaginary earthquake coming in 2018

News from the HayWired fault

Earthquake advice for Oaklanders 4: What to do