I'm a little behind with this one, regular readers might know why, but here are the top content items of the first three months of 2008 (as of 4/3/08 actually). They are in order of normalized hits (number of page impressions per day) with the total number of page impressions listed in parenthesis. There were a few near the top of the list that I was a little surprised to see and you might notice some funny math, but I didn't bother to hand edit things. Click through for the whole list.

From ENR:

The San Diego County Water Authority board of directors last week certified the environmental impact report to raise San Vicente Dam by 117 ft.

The $568-million project, to be built on top of the existing San Vicente Dam in Lakeside, will expand the reservoir to hold an additional 52,000 acre-ft of water for use during emergencies and another 100,000 acre-ft of water to supplement imported supplies during dry periods.

The Dam will be constructed of roller compacted concrete and will reportedly be the largest dam raising ever performed in the US and the largest using roller compacted concrete in the world. (Photo by O'Connor Construction Management, Inc.)

Since Friday May 2, the Chaiten Volcano in Chile has been erupting steam and ash in a most spectacular fashion for the first time since 7400 BC. The column of ash and steam rose over 17 km high and drifted over the Andes Mountains into Argentina and over the Atlantic. The terrestrial and aerial/satelite imagery of this event is amazing and frightening. Geology.com has an excellent page covering the latest info on the Chaiten  eruption.

There is concern now that the energy of the volcano has leveled off and a collapse of the ash column could happen at any time creating a pyroclastic flow of super-heated ash and vapors much like the one that buried Pompei. The photo at the left is of a lightning storm interacting with the dust and steam from the erruption, it looks like armageddon! (Photo by Carlos Gutierrez / UPV / Landov)

The regular news media as well as the geo-blogosphere are all abuzz about Monday's 7.9 magnitude earthquake in central China. Official death toll is at 12,000 right now and that's in Sichuan Province alone.  My guess is that number will swell substantially in the coming days. If you haven't seen photos and video yet, they are absolutely gut-wrenching. My heart and prayers go out to the victims of this disaster. (Photo by Liu Hai, AP)

Several geo-bloggers have posts about the earthquake. Harold Asmis of Ontario-GeoFish describes the earthquake as a "big valley-thrust earthquake" or what he calls the "Fist of God". Dave's Landslide Blog has started compiling reports of landslides related to the earthquake in this landslide prone region of China. And here is the USGS info on the earthquake.

ADAMA Software has released several updates to their popular MSE Wall design software and Reinforced Soil Slope software packages. Update 9 to MSEW 3.0 was posted on April 25. The changes include several updates related to the AASHTO 2007 code, and the option to use either the Simplified Method (AASHTO) or the Coherent Gravity Method (CGM). And there is now an option for considering live load (LL) in calculating Tmax for strength and connection but ignoring it for pullout.

Update 2.2 to ReSSA 3.0 was posted yesterday, May 5 after several itterations of the update were posted during the month of April.  The update includes a fix for handling geometries where multiple points have the same X-coordinate but different Y-coordinates. It also allows for the specification of a vertical seismic coefficient as well as a horizontal one. And the latest updates allow the inclusion of the safety map in the printout, include modified calculations of reinforcement quantities, and allow user-selected colors for reinforcement layers that now shows up in the printout too. Click through for the download link.

The Countywide Recycling & Disposal Facilities in Stark County, Ohio have a new round of problems. There has been much debate over an underground fire reportedly caused by the disposal of aluminum dross waste, a byproduct of aluminum production, dumped between 1993 and 2001. The site has long received complaints for odors and for a long time denied that there was a fire. They have also had problems with slope stability, including a failure of a portion of the south slope in 2006, possibly a result of the destabilizing effect of the fire. Early this year the Ohio EPA cited the facility for violating 8 environmental regulations after waste was found to have migrated outside the permited waste area.

Their latest problems involve a tear or leak of a geosynthetic lining that caps the facility to control gas and odors from the underground fires and regular landfill gas. The leak resulted in 500 to 5,000 gallons of leachate spilling into a sediment pond. The material fortunately did not leave the site and was pumped out of the pond and transfered to a treatment plant where their leachate usually goes. The landfill, one of the largest in Ohio, handles about 6,000 tons of trash a day, including about half of Summit County's residential garbage.

Story by way of Geosynthetica. Image from Long Live the Village Green.

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 100 seconds to travel down the mountain and engulf a portion of a nearby coal mining town. 76 people were killed, and a number of bodies were never recovered because of the massive amount of material. Since 2003, they have installed real-time monitoring equipment to warn if the mountain fails again, which seems likely based on an interesting video (requires Windows Media Player). It shows some of the massive tension cracks at the top of the limestone mountain. (Photo by Natural Resources Canada by way of Dave's Landslide Blog)

Arizona State Geologist Lee Allison blogged about some recent news coverage of earth fissures as a result of the AZGS' release of the first of their earth fissure maps. Here is what he said:

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]