The Historic American Engineering Record, a part of the National Park Service, produced a very detailed poster for identification of truss bridges. While these bridges aren’t as common in southern California, they still get plenty of use. Railroads are the most common user of these types of bridges, specifically the Pratt Truss.
Well, that was strong! I felt it here in San Diego. First time I felt my building sway and it shook for a while. USGS is now reporting the quake as a Mw 7.1, which is 11 times larger than the one yesterday. This, assuming a larger one doesn’t happen, has also been deemed the “main shock” and the 6.4 was the “fore shock”. USGS and Caltech are a bit slow right now. If you felt this one, please let USGS know once their servers are not slow or not working. They need your help!
From Caltrans and CHP, damage reports are coming in of rockfalls on 178 in Poison Canyon, a sinkhole on 178 near the Trona Pinnacles turnoff, and buckling up to 4 feet as well as large cracks in other areas. Do not drive fast through any of the earthquake affected areas. Also be aware that rockfalls will be likely in all the local mountain ranges, so be careful. State 127 near Ibex Pass is covered with rocks, and that is a fair distance away from the epicenter.
http://scedc.caltech.edu/recent/
Working map of all earthquakes in California and Nevada by Caltech. Links to USGS as well on the page.
USGS site now working!
https://earthquake.usgs.gov/earthquakes/eventpage/ci38457511/executive
Well, it has been a while but I finally made it back up to Grapevine Canyon for a more formal cleanup. I, and two others, cleaned up the upper and lower water stops along I-5 in Grapevine Canyon on Saturday, June 29, 2019. We filled nine bags and found many interesting items including a printer/copier. Next cleanup should be in early September most likely.
Representatives from the Ridge Route Preservation Organization, including myself, recently met with a few people from the Angeles National Forest regarding the Ridge Route. A summary of the meeting can be found on the ridgeroute.org site – http://www.ridgeroute.org/june-2019-update/ .
In January, I was asked to do some research regarding the potential for a landslide on the Ridge Route near Templin Highway. I thought it would be a good opportunity to get some practice writing a geologic report. While I’m not a professional geologist, I still find it a lot of fun to do . I added a copy of the report on this site, available for download. I would love to hear feedback from any other geologists out there.