Wall (2 of 2) (IMAGE) University of California - San Diego Caption A semi-gravity reinforced concrete retaining wall backs against a soil box as it undergoes a series of violent simulated earthquakes on the shake table at the UCSD Englekirk Structural Engineering Center. Credit UC San Diego Usage Restrictions Credit UC San Diego License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.