Some new research on the Newmark Displacement Method for earthquake-induced landslides indicates that the method may be on the unconservative side. The Landslide Blog provides a short summary of the paper by Li et al. (2018) that was recently published in the journal Landslides. Their research was based on physical models on a shake table, comparing the results of the model experiments with a Newmark analysis. The paper should be worth a read for geotechnical engineers practicing in seismically active areas. It sounds like some additional study is needed to confirm these results and if they are true, propose different ways of analyzing earthquake-induced landslides.
The Mt. Soledad Landslide in a La Jolla California neighborhood destroyed 3 houses and damaged others and it also shut down Mt. Soledad Road for an entire year after it occurred in October of 2007. Residents blamed the city of San Diego, and 65 homeowners filed suit, claiming that leaking pipes caused the landslide and the City should cover damages.
Last week, a superior court judge ruled in favor of the City of San Diego. So far I have not seen anything indicating if the residents plan to appeal the ruling.
One interesting note regarding the trial, the City released an 8-minute cell phone video taken by a geotechnical engineer or drilling contractor employed by the City that showed the road cracking and buckling just prior to failure. The homeowners used the video to try to make their own case. Click through for a portion of the video and a link to the full one.
As a follow up to a previous post, the San Andreas Fault Observatory at Depth (SAFOD) team has announced that they have successfully completed their drilling and obtained cores of the San Andreas Fault at depths in excess of 2 miles below the surface. The zone of interest is approximately 135-ft in length. The core size is 4-in diameter. They have cemented in a 7-in casing and the next phase of the project will be to perforate the casing within the fault and install monitoring equipment consisting of seismometers, accelerometers, tiltmeters and a fluid pressure transducer. Read on for more info and links. (Image credit: EarthScope / NSF)