Dr. Pedro A. de Alba 
- Professor of Civil Engineering
T: 603 862 1417
padealba@hypatia.unh.edu
Kingsbury Hall
Civil Engineering , UNH
Durham, NH 03824
Current Projects
When a sand which is saturated is shaken by earthquake loads, it "liquefies" which means that it temporarily loses a large proportion of its strength. Earthquakes can produce high-velocity liquefaction flow slides in slopes of saturated sandy soils; they can occur in both constructed embankments such as earth dams and in natural slopes. Such slides have produced a great deal of damage during earthquakes and, more importantly, considerable loss of life. For example, over 600 people died when their neighborhoods were buried by landslides during the 2001 earthquake in El Salvador. Professor Tom Ballestero (CiE) and I are trying to model liquefied sand as a viscous fluid by measuring the behavior of spheres and plates falling through liquefied sand in the lab. If we can model liquefied sands in this way, it should be possible to predict how these sands will behave after they liquefy, and how far they will 'run out' during sliding.
In a separate study, a group of mechanical engineering seniors, directed by Professor Barry Fussell (ME) and I are developing a new device to simulate miniature flow slides in the lab under carefully controlled conditions. The students will design and build this device as their senior capstone project in mechanical engineering. We hope to have it operating by June of 2005.
Meanwhile, I continue to be involved in the operation of an array of strong-motion instruments on an island in San Francisco Bay, where we plan to measure the ground motions produced by a large earthquake which is predicted to occur (with a 62% probability) by 2030. This site was established by Professor Jean Benoît (CiE) and I in 1992, and I continue to collaborate with the California Strong Motion Instrumentation Program in its operation.
Selected Publications
"The National Geotechnical Experimentation Site at Treasure Island, California," by J. Richard Faris and Pedro de Alba, in National Geotechnical Experimentation Sites, J. Benoit and A. J. Lutenegger, Eds., Geotechnical Special Publication 93, American Society of Civil Engineers, April, 2000.
"Acceleration Distribution and Epicentral Location of the 1755 "Cape Ann" Earthquake from Case Histories of Ground Failure," by Christopher Ellis and Pedro de Alba in Seismological Research Letters, Volume 70, No. 6, November/December 1999.
Selected Grants
"Laboratory Qualification and Field Behavior of Piezometers for Measuring Earthquake-Induced Pore Pressures," with Professor Jean Benoit. Sponsor: National Science Foundation. 1998-2000.
"Geotechnical Experimentation Planning Committee for Treasure Island, California, Deep Instrumentation Array," Sponsor: National Science Foundation. 1999-2001.
Courses Taught
- Introduction to Geotechnical Earthquake Engineering
- Foundation Design I and II
- Soil Mechanics
- Advanced Soil Mechanics
- Soil Testing for Engineering Purposes