Fellow geo-blogger David Petley of Durham University posted today about the 105th anniversary of the Frank Landslide in Canada. The slide had an estimated volume of 30 million cubic meters and took all of about […]
The East Valley Tribune published an extensive set of news features on earth fissures in their Sunday edition, including timeline, maps, videos, and an animation of how fissures form.
KPHO, CBS channel 5 in Phoenix, also has a nice video segment with great aerial shots of the 2005 fissure in Chandler Heights that triggered the recent interest in this hazard.
Here is the video he was referring to.
The only portions of the World Trade Center towers that survived the attack on 9/11 were the basement slurry walls, part of the original shoring and foundation system. The National September 11 Memorial and Museum at the World Trade Center that is currently under construction will preserve a portion of that wall making it the largest exhibit the museum will offer. The wall section displayed will be 62-ft by 64-ft.
The existing slurry walls are being incorporated into the foundation system of the new facility but not without some improvements. The are adding some kind of foundations improvements to stabilize the toe of the walls, the New York Times article calls them caissons, but I don’t know if its a tangent or secant wall or something else. They are also lining them with additional concrete and reinforcement in front of the walls along with additional tiebacks to stabilize them. In the portion of the wall that will be displayed, a counterfort wall will be constructed behind it and new tiebacks will be installed on the front. Work for the counterfort wall will be done by hand in order to avoid the existing tieback cables. All of the existing tiebacks will be left intact. Check out the NY Times article for a great graphic showing the system. (Illustration by New York Times)
ENR reports that a Tunnel Boring Machine or TBM is stuck for the second time in two weeks on Pittsburgh’s light rail expansion project dubbed the North Shore Connector Project. As we described in a previous post, the project will consist primarily of a tunnel underneath the Allegheny River. The drilling began the week of March 3 and has been progressing at a rate of 30-ft/day or 5-ft/day faster than the original goals. Read on for a location map of the project, or download the Google Earth KMZ file showing the project area. (File photo of TBM)
Yesterday the Arizona Geologic Survey (AZGS) released the first two of their 1:12,000 series earth fissure maps to the general public. The mapping program, perhaps the first of its kind in the country, came about after an earth fissures opened up in 2005 near Queen Creek, AZ, southeast of metropolitan Phoenix received much media attention. As a result, the Arizona Legislature passed House Bill 2639 of the 2006 Legislative Session that tasked the AZGS with mapping earth fissures and providing the data to the State Land Department for eventual delivery to property owners in Arizona. More after the break. (At left, the Apache Junction study area map, AZGS)
Released: 4/14/2008 12:02:15 PM
California has more than a 99% chance of having a magnitude 6.7 or larger earthquake within the next 30 years, according scientists using a new model to determine the probability of big quakes.
The likelihood of a major quake of magnitude 7.5 or greater in the next 30 years is 46%-and such a quake is most likely to occur in the southern half of the state.
[Editor] At Left: Figure 1. The colors on this California map represent the UCERF probabilities of having a nearby earthquake rupture (within 3 or 4 miles) of magnitude 6.7 or larger in the next 30 years. As shown in the table, the chance of having such an event somewhere in California exceeds 99%. The 30-year probability of an even more powerful quake of magnitude 7.5 or larger is about 46%. [/Editor]
It’s been a busy month for geo-software. RockWare has announced Version 14 of its popular RockWorks software package, a subsurface data visualization software tool that can handle maps, cross-sections, logs, fence diagrams, 3-D stratigraphic models and volumetrics. A new single-user license is $2,499 and the upgrade price for a single-user license from RockWorks 2006 is $399 (US$). Highlights of a few new features, more images and links after the break. (Images from RockWare – rockware.com)
On April 10, GeoStudio 2007 version 7.1 was released, a significant service pack update. There are numerous bug fixes and some major improvements. Geo-Slope claims that the overall speed of the product is faster when switching between analyses and views, a welcome change. There are some nice changes to the way Sketch Text is handled, which makes it easier to handle annotation of multiple analyses. And something interesting that’s new in SLOPE/W that allows you to specify a â€œSpatial Mohr-Coulombâ€ model which allows unit weight, cohesion and friction angle to vary across the geometry as a function of x and y. I canâ€™t think of a case where I would have used such a model, but it is very intriguing. More features listed after the break along with links.
April 7-11 is National Workzone Awareness Week (NWZAW) which draws attention to the hazards roadway construction crews face from motorists not heeding safety warnings. For 2006â€”the last year for which data is availableâ€”more than 1,000 died in work zones. Figures for 2007 will be released by the National Work Zone Safety Information Clearinghouse later this year. Motorists are also at risk for not following work zone safety precautions. They may face damage to their vehicles, injuries, and loss of life. For 2006, 614 motorists died in work zone crashes. (Graphic by Caltrans)
Below are a few items to think about the next time youâ€™re driving through a workzone taken from a Caltrans fact sheet. More after the break (sorry for the â€œDuhâ€ ones, but I didnâ€™t write them). As someone who occasionally works on the road and knows many more people who do, please, please remember to slow down!
- Most injuries and deaths in the Cone Zone are from rear-end collisions.
- If you slow from 65 to 55 mph for one mile, you only lose 10 seconds on your travel time.
- The first cause of death for people aged 16 to 20 is car crashes. Even if you don’t lose your life causing a car crash, it could still cost you your license or a heavy fine.
- If a car’s speed is doubled, the stopping distance is doubled twice over. For example, if a car traveling at 30 mph requires 100 feet to stop, the same car at 60 mph takes not 200 but 400 feet to stop.
- At 60 mph, you’re traveling 88 feet per second. A lot can happen in one second, so give yourself plenty of room to stop in case of an emergency.
- For the 15,000 miles of California highway Caltrans maintains, it must buy 120,000 new cones every year to replace ones run over by careless drivers.
I can hardly believe it, but today marks the one year anniversary of the launch of GeoPrac! It has been a good ride so far, things haven’t exactly gone quite like I planned, but when has that ever happened? I’m grateful to all of the visitors who frequent the site and particularly to the people who have contributed an article or geonews item. I intend to do a wrapup of the most popular articles/news items of Q1 2008 and a "state of the union" type post with some thoughts about where I intend to take the site in the coming year. But I’ve just been out of gas with the newborn in the house. I’ll try to get to it this weekend.
Here’s to a good first year and many more to come! Cheers!
— Randy (Rockman)