This is an interesting topic, but the article isn't particularly good or informative. It doesn't do anything to explain the actual scientific importance of this, if there is even one, or if this was just a notable relic showing the real world results of known geological processes. The term "Holy Grail" also doesn't seem to apply to this at all. That term is usually reserved for something that is almost impossible to find, but would be incredibly valuable if it was discovered.
As a geologist, there's no scientific importance to that specific curb at all. It is a really frequent field trip stop, though.
A lot of people go there when they lead field trips (I have too), and it winds up in a lot of photos. Mostly, it's a convenient photo-op in an easily accessible area. It's certainly not the only offset curb, but it arguably makes the nicest photo.
There are a lot of vineyards in the area that give much more impressive examples of active tectonics, i.m.o. - It's more clear that there's a gradient of deformation.
All this having been said, though, there is very frequently a lot of tension between the local department of transportation and geologists. There are a _ton_ of very significant geologic localities that have been destroyed to widen roads despite geologists begging the DOT find another way. Of course, many of these localities are roadcuts in the first place, so it's a bit hard to convince people of their significance.
Also, in case anyone's wondering why the "fault" looks like the boundary between to slabs of concrete: The actual surface trace of the fault isn't exactly at the boundary of the two slabs. It's just that one slab is mostly on one side, and the other slab is mostly on the other side. The slabs are rigid, so instead of breaking, they slide past each other.
John McPhee's Pulitzer-winning _The Annals of the Former World_ is arguably 1000 (wonderful) pages made _possible_ by road cuts... something he gleefully expounds upon.
Geologists don't get budgets to do section hills to check out their innards.
Strangely, federal highway builders do... and do.
Presto! Tons of fresh data just waiting for you to pull over and check it out...
I have a friend that refers to the local highway dept as "the department of outcrop construction".
That's also why you should never be in a car with a geologist at the wheel... We spend far too much time looking at the rocks and far too little looking at the road.
Did I miss the part where seismologists told the city, "hey, if you ever want to 'fix' this part, could you let us know first so we can discuss options?" Because, though I didn't read every word in the article, it sounds to me like the scientists woke up one day to a fixed curb and then complained because the city didn't just osmotically know this "common knowledge".
As to the city getting around to fixing something that was known to be broken in the 70s, well, that kind of snark just writes itself.
I think this is just supposed to be an interesting offbeat article, nobody is really seriously complaining. The tweet about the city destroying a "classic geopilgrimage site" is mostly tongue in cheek, her next tweet was https://twitter.com/mikamckinnon/status/746477175994408960
Agreed. I noticed that as well since I also follow Mika McKinnon. However, now I just noticed something strange. I'm blocked by Emily Lakdawalla? Since I never speak to people on Twitter, I must follow somebody which qualifies me for a block list. I really dislike that concept.
How would the city even keep track of such one-off requests? There is no database for such minute details. It would need to be generic enough to fulfill any request, but also queryable to find specific information.
Geologists have been keep track of the curb for 45 years now. City administrations and officials come and go. Surely previous officials must have known about the significance, but that "knowledge" was not passed onto the next set of administrators.
Probably the best way would be making it self-documenting: installing some sort of plaque or stand describing it and why it is scientifically interesting. Then any work crews sent out to destroy it can see the plaque and exercise some discretion in sending it up channels to ask.
Once upon a time my father discovered that the right of way along the road beside our property had several species of somewhat rare semi-protected carnivores plants growing in it. My dad contacted the county about it, they made a note of it, The mowing crew mowed over it the next day. He replanted the area with plants and seeds from his own collection, and the county put up "Do Not Mow, protected plant sanctuary" signs in the middle of the right of way. The mowing crew's solution...take down the signs so they could mow, and then put them back up when they were done.
Landmark databases occasionally do get that minute. Something like this could be listed with a location of "Southeast corner of Rose and Prospect". Of course, something demonstrating surface faulting like this would be better off in a location like a city park or something, because an offset that big would be non-fun for someone to stumble on.
I attended a meeting with the GIS guy for the University I worked for. Every Bench, utility box, smoker's ash tray, Police Emergency Call Box, CCTV Camera, Light pole etc along with who it belonged to (City, University, County, Ga Power) was logged in ArcGIS.
Cities use GIS systems for this type of thing. My city puts [some/all] of this data online. You can query street furniture, parking zones, water mains, city parks, ...
You can't, but it doesn't matter. They state that the curb runs perpendicular to the fault. No matter which way you rotate it, the "east" side is being pulled south.
It is, however, this isn't the plate boundary. The Pacific Plate is sliding northward, however, the fault boundary for the plates is the much better known San Andreas Fault. The Hayward fault is parallel to it and a few dozen miles east of it.
You're right. The Hayward fault is a right-lateral fault, striking northwest (parallel to the San Andreas) and the west side moves north relative to North America. The reporter made a booboo.
Has anyone tried to make a timelapse video out of these photos over the decades? Much more interesting than a pic of it fixed. (I didn't find anything out of a quick search.)
I think "destroyed" is going to far, they "reset" the measurement. Just because the curb is realigned does not mean it won't pull apart still. Now that it is "fixed" it would be a good time to install a pair of steel reference standards on the two curbs, then measuring the shift would be easier in the future.
This very phenomenon is why doing GIS work is infuriatingly difficult. A GPS gives coordinates relative to a constellation of satellites, but given how a large chunk of California is drifting a measurable distance, using absolute coordinates would mean all your data on the location of buildings, property lines, and underground infrastructure is increasingly inaccurate.
This is unfortunate for infrastructure but is why we're able to use GPS to measure plate tectonic motions. The geologic consequences of (relative) plate motions are also unfortunate for infrastructure, as well...
Out of curiosity, I just checked to see where the fastest velocity on earth relative to a no-net-rotation reference frame is. Using data from the Global Strain Rate Map[0] (I think this is the study, I was emailed the dataset by the first author a couple of years ago), the maximum velocity is on the Philippine Sea Plate immediately east of Taiwan, clocking in at 471 mm/yr. So any undersea points measured in lat/lon (i.e. WGS84) will be inaccurate at almost half a meter per year (or 0.000005 degrees).
Curious how you could solve that. I guess you would need to time stamp the coordinates. Then if you had data on how each region has moved you could calculate new coordinates over time. Sounds painful.
There's many, many frames of reference you can use to map your GPS data into actual on-ground coordinates. There's a number of systems that do this, but usually it's done with a projection from abstract GPS points into real-world positions via something like this: https://en.wikipedia.org/wiki/World_Geodetic_System
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[ 3.1 ms ] story [ 114 ms ] threadgive em a bonus this year
A lot of people go there when they lead field trips (I have too), and it winds up in a lot of photos. Mostly, it's a convenient photo-op in an easily accessible area. It's certainly not the only offset curb, but it arguably makes the nicest photo.
There are a lot of vineyards in the area that give much more impressive examples of active tectonics, i.m.o. - It's more clear that there's a gradient of deformation.
All this having been said, though, there is very frequently a lot of tension between the local department of transportation and geologists. There are a _ton_ of very significant geologic localities that have been destroyed to widen roads despite geologists begging the DOT find another way. Of course, many of these localities are roadcuts in the first place, so it's a bit hard to convince people of their significance.
Also, in case anyone's wondering why the "fault" looks like the boundary between to slabs of concrete: The actual surface trace of the fault isn't exactly at the boundary of the two slabs. It's just that one slab is mostly on one side, and the other slab is mostly on the other side. The slabs are rigid, so instead of breaking, they slide past each other.
Geologists don't get budgets to do section hills to check out their innards.
Strangely, federal highway builders do... and do.
Presto! Tons of fresh data just waiting for you to pull over and check it out...
I have a friend that refers to the local highway dept as "the department of outcrop construction".
That's also why you should never be in a car with a geologist at the wheel... We spend far too much time looking at the rocks and far too little looking at the road.
As to the city getting around to fixing something that was known to be broken in the 70s, well, that kind of snark just writes itself.
Geologists have been keep track of the curb for 45 years now. City administrations and officials come and go. Surely previous officials must have known about the significance, but that "knowledge" was not passed onto the next set of administrators.
You'd be amazed what municipalities are using ArcGIS for these days. Well, I was, at least.
Zim: "Worse...or better?"
(Or even post something on Twitter like "Hayward readers – we need a quick favor! DM if you have a camera and half an hour. Credit given.")
Anyway, here it is: https://oaklandgeology.files.wordpress.com/2016/06/rosepros-...
And article from where it comes from: https://oaklandgeology.wordpress.com/2016/06/27/loss-of-an-i...
Is that right? The picture seems to show the opposite, and I thought the Pacific Plate was sliding north, relative to the American Plate.
The real world is a complicated, ugly place.
Out of curiosity, I just checked to see where the fastest velocity on earth relative to a no-net-rotation reference frame is. Using data from the Global Strain Rate Map[0] (I think this is the study, I was emailed the dataset by the first author a couple of years ago), the maximum velocity is on the Philippine Sea Plate immediately east of Taiwan, clocking in at 471 mm/yr. So any undersea points measured in lat/lon (i.e. WGS84) will be inaccurate at almost half a meter per year (or 0.000005 degrees).
[0]: http://onlinelibrary.wiley.com/doi/10.1002/2014GC005407/full