The Jungle Hill landslide

23 November 2020

Jungle Hill is an odd plot of city-owned land off 38th Avenue in East Oakland. It’s been something of an embarrassment since it collapsed in landslides in the 1910s, marring the carefully tended image of a new and very desirable neighborhood. Landslides are more common in Oakland’s low hills than people think.

Jungle Hill is east of Fruitvale and west of High Street, making it sort of an in-between spot in terms of today’s neighborhoods. Here it is, marked with a red asterisk on the street map.

The area was empty countryside until 1906, when things changed dramatically with the San Francisco earthquake on 18 April. Oakland’s population essentially doubled overnight, and the big landowners leapt into action, putting their long-planned schemes into action as fast as they could. The default scheme at the time was to set up a streetcar line serving a tract of land, then subdivide the tract and sell the lots to people who would build homes on them. The developer would impose various restrictions to assure buyers that they would have neighbors like themselves building houses like their own.

Such was the case in the area of Jungle Hill. Beyond the presence of the streetcar line, the big attraction of the area was its elevation. Here’s the exact same area on the geologic map.

Long-time readers will recognize the orange blobs as the set of ancient gravel hills that I call the Fan. They stand above the flats by a hundred feet or more, which made them desirable home sites, and they’re still Oakland’s homiest middle-class neighborhoods, delightful for rambling. Foothill Boulevard runs along their lower edge. Jungle Hill sits on the western edge of Lobe 6 of the Fan. With that background, let’s zoom in and get oriented.

The streetcar line, spine of the development, went up 38th Avenue, which was named Liese Avenue at the time (a little spur up by the freeway still has that name). The street is still extra wide and displays the slope above Foothill Boulevard well. In 1906, Foothill Boulevard was the brand-new road to Hayward, a great source of city pride and the key to developing the lower hills.

The tract extended several blocks on either side of Liese Avenue. This area was developed starting in 1906 as Boulevard Park, “the most desirable property for home sites that has ever been placed upon the market.” Soon the ads proclaimed, “Elevated land! Magnificant marine and landscape view. All streets macadamized, curb and stone gutters, with 5-foot sidewalks. Water, gas and sewered. Trees and palms in profusion. New electric car line through the tract.”

After listing the prices and terms, they ended, “No Mongolians need apply.” This is how Oakland used to be.

Now we zoom in to the Jungle Hill site.

During heavy rains in January 1911 the hillside north of Ransom Street, overlooking that dogleg at the north end of Santa Rita Street, gave way. Three years later, early in the morning of 20 January 1914, in the midst of a series of storms that ravaged the whole west coast, the hillside farther downhill started moving. The Joneses across the street nearly died when their gas line broke. More sliding happened a few days later.

Here’s what the hillside looks like today from the north (well, in 2014 when I last wrote about this area). Santa Rita Street is hidden at the foot of the hill. The slope to the right of this view (visible in the newspaper photo) is even higher and steeper, but no one seems worried about it and I saw no obvious signs of ground movement in a visit this week.

This setting is very reminiscent of the McKillop Road landslide, which is also on the edge of a lobe of the Fan. Indeed, both sites hosted landslides soon after their development, in the years before 1910. Unlike the McKillop slide, which was notorious in the 1930s and again in the 2000s when it reawakened, Jungle Hill never appeared in the newspapers again, although a MacArthur Metro story from 2007 claims that more sliding occurred in the 1930s.

In any case, the property was long vacant when an early land trust, the Santa Rita Land Trust, scraped together the money to buy it in 1977. Residents put a lot of work into it, installing a path of railroad-tie steps that’s now crumbling. But when the trust petered out and went defunct, the land went to the city.

The hillside has the hummocky appearance typical of landslide sites.

An old wall that once bolstered a homesite looks to be in good shape.

And the climate and views that once made this area so desirable are still there.

The streets above and below aren’t blatantly crumbling. The site appears to have been so stable since 1914 that it could be built upon today. That would be politically difficult, I’m sure.

While I was visiting, I had to see the Carrington Stairs again, known to generations of local kids as “the 72 steps.” It’s still impressive from the top, if a bit grim.

But when you get down, it is fantastic. Click this picture for its full 1200-pixel glory and pay it a visit whenever you’re around.

Posted in Landslides, the Fan | 11 Comments »

The changing identities of the Leona Quarry

9 November 2020

Last week I finally gave in and returned to the high hills — for exercise, as permitted by the county health authorities — and couldn’t resist a reconnaissance of the Leona Heights area. It’s Oakland’s boldest and most rugged region. Here it is from Knowland Park, above the zoo.

Most Oaklanders may know it, though, as the mountainside with the huge scar on it overlooking I-580, the former Leona Quarry.

The quarry was first opened by the Ransome-Crummey Company in 1904 and ended operations under Gallagher & Burk in 2003, but it changed hands (and names) several times over the years, making its detailed history hard to trace. Also, newspaper accounts often confuse it with the Leona Heights quarry, which was at the site Merritt College occupies today.

The quarry was first made feasible by an extension of the Laundry Farm railroad, above Mills College. It was originally high up a steep grade, as shown by the pick-and-hammer symbol in the 1915 topographic map.

I believe it was up there because the bedrock was well exposed, making excavation unnecessary at a time of heavy reliance on hand labor. The 1947 map shows that operations had moved downhill, and quite a bite had been taken out of the hillside.

And the 1980 update of the 1959 map shows the quarry scar at its ultimate size.

The whole time, this hillside was being quarried exclusively to make crushed rock. There was a huge demand for coarsely crushed stone in the days before asphalt and concrete pavement. The gold standard for city streets in the late 1800s and early 1900s was macadam, which has completely disappeared since then. You’ll only see it in silent movies.

A macadam road started with a shallow excavation that was filled with several layers of crushed rock, of successively finer grade, topped with fine gravel or rock dust. The jagged, blocky texture of crushed rock made macadam roads exceptionally firm in comparison to plain dirt or gravel, and they didn’t turn to mud in the rainy season.

As Oakland grew, filling in the harbor and airport and covering East Oakland with suburban tracts on an ambitious street grid, its quarry owners prospered, especially the well-connected ones who could arrange favorable contracts and keep wages low. Plain old crushed rock — road metal — was in high demand. Although there were still good markets for crushed rock after the macadam era ended, things were not the same. The Leona Quarry outlasted all of its competition in Oakland thanks to its remote location, good rail transport and ease of production. But eventually the city expanded to the quarry’s doorstep, the quarry ran out of easy rock and the show ended in 2003, when I took this shot of the north end of the property.

That’s when the site took on its next identity — a townhome district. The rock no longer matters.

But it used to. I think the Leona Quarry started running into problems as the standards in the rock business grew steadily stricter.

Leona Heights, the mountain, consists of a body of much-altered volcanic material of Jurassic age that I refer to on this blog as the Leona volcanics. Its eventful history left it impregnated with pyrite, iron sulfide, in many places. A little farther northwest, in the valley where route 13 splits from I-580, there was enough pyrite to support at least two mines. Down at the Leona Quarry there wasn’t as much, but it does exist and, as it does in the old mines, pyrite decays in the air and rain into iron oxides and sulfuric acid. The oxides turn brown, staining the Leona volcanics this typical color.

They also stain the stream water, as seen here in the headwaters of Chimes Creek above the quarry (and elsewhere in the hills).

The west side of the quarry was full of this “red rock” while the east side consisted of a dense blue-gray siliceous rock, more like this specimen I collected there back in 2009.

Whereas the red rock was useless for things like concrete aggregate because of its pyrite content, this was the good stuff. Nevertheless, the market for excellent road metal came to be dominated by huge outfits like Granite Rock — whose co-founder, Arthur Roberts Wilson, started his career at the Leona Heights Quarry back in the 1890s.

Meanwhile today, the former quarry is now a townhome plantation, set at the bottom of a high, steep rocky bowl.

There is no guarantee that the quarry’s second identity will last forever. Fire, earthquake and rockfalls can overcome any defense given enough time (although the Leona Quarry development has a GHAD that maintains the defenses). Zoning changes and real-estate fashions can undermine such enterprises as surely as physical hazards. There is no guarantee that anything we build will last a century, like the quarry did. Like the ancient philosopher said, everything flows.

Posted in Leona volcanics, Quarries and mines | 2 Comments »

Upper Indian Gulch

26 October 2020

When I last featured Indian Gulch on this blog, it was about the easy part, mostly a stroll up Trestle Glen Road. It ended with this glimpse of the living Indian Gulch Creek, bounding down the rock slopes of the Piedmont crustal block on its way to culverted oblivion beneath the elegant Trestle Glen neighborhood.

Upper Indian Gulch lies within Piedmont and the west fringe of Montclair that looks down upon Piedmont. Nowhere is the creek up there accessible to passers-by; if you want to see it you have to buy a house whose lot includes it, or make friends with someone who owns such a house. You’ll have to imagine it running in the dark underneath the street, as it does along La Salle Avenue just above St. James Drive.

Here’s an overview of the upper creek from Google Maps terrain view. The creek has three branches; the west fork is the main branch. To be a stickler, that fork should properly be called Indian Gulch Creek and the other two are just tributaries. The old property line between the two middle Peralta ranchos ran up this valley, Vicente’s on the left and Antonio’s on the right. Later the same line separated the Oakland and Brooklyn Townships of Alameda County. Today neither the ranchos nor the townships are relevant any more, but the boundary influenced the pattern of land ownership a century ago as Oakland expanded its territory and developers shaped the outskirts.

A stroll here is a workout. Part of my Ramble 4, Uptown to Montclair, goes up the creek’s middle fork but the steepest part is pedestrian-unfriendly. Three years ago I featured an excursion into the valley of the east fork. That pretty much exhausts the possibilities in those two valleys. In the west branch, two dead-end roads will take you to the floor of the valley, though the creek is not accessible. Indian Gulch Road leads down from Glen Alpine Road, just above the word “West”:

And Calvert Court swoops from Blair Avenue down into the creek’s highest watershed, where Oakland’s most isolated properties lie.

Here and there, you can get a look at the bedrock under the watershed: sandstone and mudstone of the Franciscan Complex.

And it’s hard, on Piedmont’s winding streets, to grasp the contours of the land. This view across the middle fork at Hampton Park is about as good as it gets.

Really, the best experience of these headwaters is on the rim roads that encircle the watershed. They aren’t photogenic in ways that my camera have caught many times over the years, but the views glimpsed through the trees and past the homes have always pleased my eye.

Looking east-northeast up Hampton Road at Sea View is a good view of the high rim of the east branch, topped by Pershing Drive.

By all means visit Oakland’s best bedrock there.

And don’t miss Wood Drive, along the north rim, where this excellent outcrop of Franciscan metachert awaits.

Indian Gulch is a good candidate for a circumambulation.

Posted in Franciscan rocks, Oakland streams and water | 1 Comment »

Earthquake advice for Oaklanders 4: What to do

12 October 2020

The first thing to do about earthquakes in Oakland is PREPARE! Well OK, but prepare for what?

To get our attention, a team of federal and state geologists got together a few years ago and prepared an elaborate forecast of a seriously large earthquake on the Hayward fault, a magnitude 7 rupture from Point Pinole down to Hayward, and the whole process of coping with and recovering from it. They called it the HayWired Earthquake Scenario to emphasize the 21st-century vulnerabilities of the wired East Bay, where everything depends on electricity and the internet. The scenario was made to be studied closely by people of all kinds whose business is planning ahead. It will do for my purposes.

The HayWired earthquake starts with a rupture on the fault right underneath the Crestmont neighborhood in Oakland, and the rupture proceeds in both directions from there. Strong shaking lasts for a good thirty seconds.

Look around where you’re sitting and picture it. You feel as if two big strong people are shoving you back and forth between them. Impossible to stay standing. More big strong people are going nuts around you: knocking over your bookshelves and dressers, pulling everything out of your cabinets, smashing your aquarium and your floor lamps. Trees outside are snapping off limbs, vehicles on the road losing control. The lights go out. Your laptop flips to the floor, suddenly on battery power. The quake itself roars like a locomotive, and the buildings around you snap, crackle and pop. You hear screaming and car alarms and shattering glass. It goes on and on.

That thirty-second period is what “Drop, Cover, Hold On” is about. If you have the presence of mind to do anything at all, that’s all you should do. Drop to the floor. Take cover underneath something. Hold on to it. Forget about standing in doorways, forget about running somewhere, try not to shout useless things. This is why we have earthquake drills, to make this behavior a life-saving reflex.

The hard shaking will stop after that endless thirty seconds, succeeded by a lot of reverberations and aftershocks. As soon as you can, get up and deliberately make ready to leave, even if everything seems okay for the moment. This is the stage I’m talking about when I say PREPARE. For details, start with Ready.gov or your own favorite preparedness site.

A couple other things. Stay nearby; don’t try to skip town in your car. Don’t tie up the phone system; text one out-of-town contact and save your phone battery. And be prepared to wait; everything will take time. I made these points in more detail in another post.

We have a hard time facing the threat of large earthquakes. The prospect rouses fear, and too much fear is paralyzing. I suggest thinking in terms of three categories, a set of three mental lists, labeled “Face it,” “Calm down” and “Perk up.”

Face it

I can guarantee you that the Big One will be worse than you imagine. Face it. Bad as it will be, though, that part will pass in less than a minute. The aftershocks, in their own way, will be just as bad, and they’ll go on for months. Maybe this is more of a “thinking about it won’t help” list. Move on to the second list.

Calm down

The Big One will kill hundreds of people, but I can also almost — almost — guarantee that you won’t be one of them. Calm down. If even 1000 people are killed in the East Bay’s population of 2.5 million, the odds against you are so small you can ignore them. Pay attention to the more realistic threats that will hinder your life, not kill you. That leads to the third list.

Perk up

Think about the different spaces in your life — where you sleep, where you work, where your most important stuff is — and come up with tangible ways you can prepare. Perk up. For instance, there are apps, there are ways you can look forward to helping science. Other things that perk me up may appeal only to other geo-geeks, but they include visiting the fault while it’s still sleeping, and the occasional game of quakespotting.

Back in my first post of this series, I said I was thinking about earthquakes because we’re in a year of disasters, and the kind of disaster I know the most about is earthquakes. The reason this really matters to me right now is that while every disaster changes us, every disaster ends. In effect, the aftermath is a new age.

Oakland’s last earthquake, in 1989, changed everyone who went through it — it imposed a certain solidarity upon us. And almost all of the wounds the quake gave us have healed stronger. Damaged buildings have been replaced or renovated.

Freeways and water mains and power lines have been strengthened. Households are better prepared and rehearsed. The city is requiring residences to have their dangerous soft stories fixed.

The disasters of 2020 have affected areas larger than Oakland or even the Bay area. Wildfires have struck huge regions, the unemployment crisis has hit the whole state, and the pandemic is a national tragedy. But they’ll all end. The Trump administration will end. And the next big earthquake, in all its instant and drawn-out consequences, will end. A time will come when we can make some long-awaited changes and build back wiser and better.

This set of posts addresses Oakland’s seismic situation, but that’s only one of the natural hazards we’re prone to. There’s also the complication of living not just with earthquakes, but with everything else about California, like our droughts and floods, our heat waves and landslides, our wildfires and our economy. Earthquakes have intersectionality with all of these other risks — what we do about those risks affects how we act with respect to earthquakes, and vice versa.

For example, landslides can be triggered by winter rains or earthquakes, so consider a big earthquake in winter. As I wrote here for the 150th anniversary of the last big East Bay earthquake, “If we’re lucky during the next big quake, as we were in 1868, the ground will be dry. If we aren’t, and the ground is waterlogged, well, heaven help us because we’ll get both kinds of landslide at once.”

In that perspective, the growing gorilla in the room (to mangle a metaphor), the one that makes all the others worse, is climate change. I thought that Benjamin Hatchett of the Desert Research Institute, in Reno, summarized the situation well in a recent paper about atmospheric rivers: “California’s complex terrain, biogeographical diversity, proximity to the data‐sparse North Pacific Ocean, and large population and economy provide an environment both dependent upon and highly susceptible to weather and climate extremes. These include extreme precipitation events, flooding, land‐surface mass wasting, multiyear droughts and pluvials, heat waves, and wildfires. Many of these extremes are projected to worsen or become more impactful in a warming climate.”

Climate change will force all of us in this civilization, leaders and neighbors alike, to up our game.

Posted in Earthquakes | 1 Comment »

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