This walk, the first in a series of walks located on or alongside the Hayward Fault in Berkeley, will first take you along some of the streets and paths that criss-cross the fault, while admiring the houses which are the most vulnerable if the fault should rip open here, and then will show you some of the wildfire hazards which will no doubt increase the risk of a firestorm when we have the next great earthquake on the fault.
As you look at some of the stupendous views across the Bay to San Francisco along the way, and try to imagine the movement of the Pacific Plate underneath you as it slides past the North American Plate a little to the east, you will be awed by the magnitude of the devastation that will likely occur very soon.
As a bonus, you will get to traverse four of the most beautiful paths or walkways in the system administered by the Berkeley Path Wanderers Association, and hopefully get a new appreciation for the work they do in making our City of Berkeley ever more beautiful. Enjoy it, while it is still intact.
This walk is notable for the absence of almost all evidence of the Hayward Fault. It has been so long a time since it last ripped open that nature, and more recently mankind, have completely obliterated its traces. Fault creep, which is visible evidence of slow movement, typical on the Hayward Fault south of Oakland, is almost completely absent on this section. As the saying goes though, absence of evidence is not evidence of absence, as we will come to find out very soon.
This walk is about 2 miles long, with a total rise in elevation of about 200 feet. Some of it is quite steep. However it is designed so it rises gradually to the highest point, and the steepest part is downhill at the end. It is not wheelchair accessible. Parking is available on Euclid Avenue alongside Codornices Park.
Here is an overview image, courtesy of the USGS and Google Earth, with the red line being the approximate location of the fault (plus or minus 100 feet or so), and the black line being the route of the walk. The start is at the white square in the top left corner.
To summarize, walk south through Codornices park, past the playgrounds, across the ballpark to Berryman Reservoir, south on the path around the reservoir, end then emerge onto Euclid Avenue at Codornices Road. Walk east and then north-east up Codornices Road all the way to the top and back. Continue south on Euclid Avenue a few paces and turn east up Rose Walk.
When Rose Walk ends, keep going on Rose Street to Greenwood Terrace, down Greenwood Common and back, south on Greenwood Terrace to Buena Vista Way, east on Buena Vista Way to La Loma Avenue, south on La Loma to La Vereda Road, east on La Vereda to Cedar Path, and down (west) on Cedar Path to La Loma.
Then go north on La Loma to the back of Hillside Elementary School, down the steps and through the back yard of the school, out the front and then north on Buena Vista to La Loma Steps, down La Loma Steps (west) to Le Roy Avenue, north on Le Roy to Rose Walk, and then east on Rose Street to Tamalpais Road.
Go north on Tamalpais Road all the way to Tamalpais Path, and west down Tamalpais Path to the bottom, where you will find the Tots Playground where you started.
The walk starts at Codornices Park, at the Tots Playground, built right on top of the fault. Try to find any trace of the fault. You won’t find a thing!
Continue south past the playgrounds, and check out the picnic table at the intersection of the north and south forks of Codornices Creek. As you sit here contemplating what you are about to see on this walk, or rather what you won’t be seeing in terms of direct evidence of the fault location, note that this picnic table is, as near as can be determined, right on top of it. If it starts to rock, get ready to run.
Walk south across the ballpark near the bank to the east of the playing field, and try to see any evidence of the fault in the bank that separates the grass from the trees. Curve around to the west, and go through the gate to Berryman Reservoir.
Berryman Reservoir and Codornices Road
Take the pathway to the south around the west side of Berryman Reservoir, a treated water reservoir built behind an earthen dam in 1878. The Hayward fault runs just a few feet to the east of the reservoir. During the 1990′s, seismic studies revealed that a major seismic event could damage the dam, possibly creating a deluge of 15 million gallons of water cascading down the hill to the west.
EBMUD began to lower the water level in 1998, and by 2006 new pipes had been built to bring water from Summit Reservoir higher up in the hills to the customers formerly dependent on the Berryman Reservoir. The reservoir is now empty, and no longer is a hazard to the homes and businesses downhill. Plans are being made to build a new seismically safe storage tank at the site.
Walk south on Euclid just a few paces, and then turn east up Codornices Road. As you begin to round the curve to the north-east, look south-east at the back of houses which actually front onto Rose Street and Rose Walk. They are all faced with wood, and they are all sitting on top of the fault. Although wood frame houses fare quite well in earthquakes (provided they are anchored down), they do not fare well in the fiery aftermath. Note though, that they have tile roofs, which is a plus, but see also that there is far too much rampant vegetation surrounding them.
Keep going up Codornices Road to the top, and look down at the roof of Berryman Reservoir to the west. Note that the fault crosses Codornices Road just as you begin on the upslope, and runs along the back of Berryman Reservoir. The houses at the top of Codornices Road are extremely vulnerable, being so close to the fault, and backing onto the uncontrolled vegetation of Codornices Park.
Walk back down Codornices Road to Euclid Avenue, and go a few steps south to the beginning of Rose Walk.
Rose Walk and Rose Street
After reading the plaque describing its history, turn east up the Rose Walk Steps. As you approach the top, look uphill. Is it my imagination, or are the steps twisting here? Hard to tell, and even harder to tell whether it is due to old age or fault creep.
As you leave Rose Walk, just before you keep going east on Rose Street, look at the curb opposite, on the south side of Rose Street, alongside the wood-shingled house at the corner of Le Roy and Rose. The fault runs right through here, to the east of that house. Do you see any evidence? None whatsover. No fault creep, no movement. A ticking time bomb.
Continue east on Rose Street for a few steps, and then turn south on Greenwood Terrace.
Greenwood Terrace and Greenwood Common
Go west through Greenwood Common, a modernist residential enclave soon to be the subject of its own architectural book, and note that, in contrast to what you will see later on Tamalpais Road, the homes are being maintained with a defensible space around them. In the event of a firestorm they will likely survive although, as is the case throughout the Berkeley Hills, survivability is dependent as much on your neighbors maintaining a defensible space as well.
If you stand at the end of Greenwood Common, and look down between the houses on either side, you will see tangles of undergrowth and tangled dead vegetation on the properties down the hill. That is exactly where the fault runs, and those homes are the most vulnerable if the fault should give way here.
Buena Vista Way and La Loma Avenue
Just before you turn east on Buena Vista Way, look west at the view of Mount Tamalpais in the distance, and note the elegant white stucco house with the red tiled roof to the right at 2599 Buena Vista Way. That house is built right on top of the fault, as is the house to the left of it. Later on, as we begin to go down the La Loma Steps we will see several other gorgeous houses built right on top of the fault.
Go east on Buena Vista Way almost to La Loma Avenue, and at the last house on the right at the corner, which is surrounded by dense vegetation, look through the bushes at the PG&E gas service at the north west corner of the house. As is typical of most houses in Berkeley, no Emergency Seismic Automatic Gas Shutoff Valve has been installed. This will be a triple whammy in the next earthquake, being a couple of hundred feet from the fault, surrounded by dense flammable vegetation, and not having an automatic gas shutoff valve.
Fires caused by these situations will, just like the 1906 Great San Francisco Earthquake, spread rapidly, and will be totally beyond the capacity of the Fire Department to deal with.
Turn south on La Loma Avenue. Here the fault is just to the west of the houses on the west side, so close to them that it might as well be right underneath. When you get to La Verada Road, just before you turn east up La Verada, turn and look at the house on the corner. Not only is it stunningly beautiful, but it has a well cleared defensible space around it, and is of a fire-resistant stucco and composition roof construction.
La Vereda Road and Cedar Path
Turn east on La Vereda Road and look at the first house on the south side. That un-reinforced brick chimney, already leaning, no doubt will fall through the wood shingle roof when the fault, just 200 feet to the west, starts to move. Many brick chimneys in Berkeley toppled during the 1989 Loma Prieta Earthquake, and it is surprising that this one survived. That ancient, dried out wood shingle roof will burn up like tinder in a minute, and contribute to the firestorm.
Keep going east and then south on La Vereda Road, and look east up the hill at the vegetation surrounding the houses, and the potential for a firestorm. This photograph was taken in the spring when the trees were green, but in the fire season in the fall, it is a very different story.
Keep going a couple of hundred feet and turn west on a poorly marked little separate piece of Cedar Street, and walk downhill to the last house. The entrance to Cedar Path is very hard to find through a small gap on the right. Be careful, because these steps are very steep and uneven. As you descend, look to the south at a patch of vacant land towards a house in the east side of La Loma Avenue. The fault runs right under that house to the bottom of Cedar Path.
As you navigate the difficult terrain at the bottom of the path, you can imagine how this topography was created through the twisting and heaving of past earthquakes.
Go north on La Loma Avenue, and note that there are no utility poles on this street. The electrical, telephone, and cable TV services have been undergrounded. I think the reason is obvious, but when you look at the access covers in the area here right on top of the fault, you may well wonder how they will survive intact when the fault splits, even though they are underground.
The Former Hillside Elementary School
Keep going north on La Loma, and Just before you get to 1550, opposite the intersection of La Vereda Road, you will see a gap in the concrete wall. Go down those steps to the back of the abandoned Hillside Elementary School. It was abandoned for a very good reason. As you stand at the bottom of those steps, looking over the roof of the school, you are standing right on the fault. Scary, isn’t it?
Don’t dally too long here. If the earthquake happens, you are trapped. The steps you just came down will crumble, and the building in front of you will collapse. Instead, turn left down another flight of crumbling steps, then right onto the concrete pad at the back of the school. Before you on the ground is a filled-in concrete cut where, during the 1970′s, a deep trench was dug to study the fault, in the wake of the Alquist Priolo Earthquake Fault Zoning Act of 1972. Based on the findings, the school was quickly closed and abandoned in 1983
Walk south and around the end of the school, designated as a National Historic Landmark. Designed by Walter Ratcliff in 1925, Hillside has an auditorium with a wood beam ceiling, wood floors, and a view of San Francisco Bay. It was listed as a Berkeley landmark in 1980 and was placed on the National Register two years later.
What to do with it now is a real dilemma, because seismically retrofitting such an old structure to the standards needed to withstand a surface rupture, when it is sitting partly on the fault itself, would cost many millions of dollars.
Buena Vista Way and La Loma Steps
Continue north past Hillside School and along Buena Vista Way. Note the interesting house design and architecture along both sides of the street. The center of the fault zone here runs right underneath the houses on the east side of the street, getting closer to the road itself until it crosses just before the entrance to La Loma Steps.
If there is a fault surface rupture here, it will likely be quite near or even under this lovely house. If I lived there, I am not sure whether I would want to know what is very likely to happen within the next few years. Most people who live in houses like this, built so close to the fault, are completely oblivious to its location and its dangers, because they moved in many years ago before the fault was accurately mapped, and before the probability of the next earthquake on this fault was made known.
Keep going on Buena Vista almost to the point where it turns east, and prepare to turn west on La Loma Steps, built in 1910, now a City of Berkeley Landmark. Just before you do so, take another look at the elegant house on the corner of Buena Vista Way. You may remember we looked back at this as we left Greenwood Terrace. The fault zone runs under that house. Now go down (west) La Loma Steps. As soon as you have gone down a few paces, turn back and look at the lovely herring-bone brickwork of the pathway.
This brickwork, together with the two houses on either side, will likely be destroyed in a surface rupture here on the Hayward Fault, because it runs right underneath this location.
Continue to the bottom of the steps, and before you turn north on Le Roy Avenue, turn around and read the plaque describing the history of the La Loma Steps.
Le Roy Avenue
As you walk north on Le Roy Avenue and admire the houses on the east side of the street, be aware that the owners have to deal with the fact that the fault here runs right through their backyards. As you can see occasionally between the houses, and as we saw when we looked down from Greenwood Common earlier in this walk, there is much uncontrolled vegetation growing up the hillside behind these homes, increasing the risk of a post-earthquake firestorm.
Just before you turn east again on Rose Street, take another look at the house on the south-east corner of Le Roy and Rose St, and see if you can see any evidence of the fault. This is the area we looked at earlier as we left Rose Walk to go north on Rose. There is absolutely no sign of any fault creep here, no evidence whatsoever that two massive pieces of the earth’s crust are slowly sliding past one another.
Go east on Rose Street and turn north on Tamalpais Road. As you go along Tamalpais Road, look to the north-west and note the dense vegation surrounding the houses, which almost climb up to the sky.
To the west of the houses on the west side of Tamalpais Road is a canyon going down to Codornices Park, and at the back of the houses on the east side is a very steep hillside going up more than 500 feet. In September and October, the Santa Ana Winds, more typical in Southern California, could fan a devastating conflagration in this area as they did in the Oakland hills in 1991. The Hayward Fault in this area runs to the west of the houses on the west side of Codornices Road through Codornices Park.
The point to note as go north on Tamalpais Road is how narrow the road is, and how many cars are parked along the road. Access by fire trucks would be very difficult, as was the case in the Oakland Hills Firestorm of 1991. Another similarity between this area and the Oakland Hills Fire area is the steep terrain.
Keep going north on Tamalpais Road and then turn west down the steps of Tamalpais Path.
The thing to note about this area is the dense vegetation so close to the houses, an extreme hazard in the fire season, quite apart from fires caused by the anticipated rupture on the Hayward Fault. Nobody in this area has created a defensible space around their home.
Keep going down the steps, and near the bottom and you will pass a small gate on your right. This is the entrance to a path leading to a beautiful waterfall on Codornices Creek, which is spectacular in January or February during the rainy season. Unless you are very fit, and have lots of time, save that trip for another day.
As you get to the bottom of the steps at Codornices Park, turn around and look at the steps you just descended.
It is likely that the fault runs under Tamalpais Path right about here. It would take an argument between a seismologist and a structural engineer to decide whether that crack is the result of the fault moving, but it sure looks to me like this part of the path is twisting towards the north, which is the direction of movement of this portion of the tectonic plate.
Turn south, and a few steps into the park you will be back at the start at the Tots Playground.