The Geotechnical Extreme Events Reconnaissance (GEER) report for the moment magnitude 7.7 earthquake that struck the Mexican State of Michoacan on September 19, 2022 is now available. The earthquake was an interface subduction earthquake along the Middle America trench megathrust near the central Pacific coast of Mexico. Approximately 6,000 houses were damaged, as were 116 schools. There were two fatalities attributed to a building collapse in the earthquake and another two fatalities in a M6.9 aftershock several days later. The report can be downloaded from the GEER association.
Italian Court Action Likely to Harm Efforts to Mitigate Earthquake Losses
On 22 October, 2012, an Italian court convicted six internationally respected scientists of manslaughter. The scientists Enzo Boschi, Giulio Selvaggi, Franco Barberi, Claudio Eva, Mauro Dolce, and Gian Michele Calvi have been sentenced to prison terms, barred from public office, and ordered to pay court costs and damages.
Their offense could have been avoided by precisely predicting the timing and nature of the tragic 2009 earthquake in L’Aquila. However, such precise, short-term earthquake prediction of the type evidently sought by L’Aquila is currently impossible. Because of the ungainly complexity of earthquake systems, knowledge of physical details is incomplete; the diverse expressions of earthquake processes deliver contradictory messages; and measurements of earthquake phenomena can be inaccurate. Glaringly, the indictment accused the scientists of having provided “incomplete”, “contradictory”, and “inaccurate” information.
[Editor] Click through for the rest of the press release from the GSA. [/Editor]
Chile Earthquake 2010 – Magnitude 8.8
The Claremont Tunnel – Designed to Survive Fault Rupture on the Hayward Fault
The Claremont tunnel beneath the Berkeley Hills on the east side of Oakland is a water supply tunnel that serves over 800,000 customers in Richmond, Oakland, San Leandro and neighboring communities. One of the unique things about the tunnel is that it crosses the active Hayward Fault. Most of the time when you talk about designing for earthquakes youâ€™re talking about designing to withstand the seismic forces. In this case, the designers needed the water transmission tunnel to withstand up to 7.5-ft of offset due to fault slip and still maintain a minimum level of service. (Photo credit: Sue Bednarz, Jacobs Associates, Inc. by way of Civil Engineering Magazine)
This post describes the relatively recent Claremont Tunnel Seismic Upgrade Project as reported in Civil Engineering Magazine (May 2008, v. 78, no. 5, pp 58-63, 96-97).