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Earthquake engineers and scientists headed for Napa quake zone

NOTE: The following was submitted by structural engineer and winery earthquake researcher Joshua Marrow.

Marrow’s name may be familiar to many because he has written extensively for Practical Winery & Vineyard.

He is requesting that wineries in the quake zone reach out to him regardless of whether they have been damaged or not. His efforts will be directed to helping develop a set of “best practices” for the future.

Wineries will be granted anonymity if they wish.


Structural engineers and earthquake science researchers are making their way into the region to study the effects of this moderate seismic event.

One such researcher is Joshua Marrow, a practicing structural engineer and earthquake risk consultant based in San Francisco.  Mr. Marrow has studied the effects of earthquakes on wineries and wine production facilities since 1997.  Mr. Marrow will be arriving in the affected area early Monday morning with his engineering team.  He will be working closely with the Earthquake Engineering Research Institute (EERI) ( research team and participating in the California Earthquake Clearinghouse (

Mr. Marrow’s team and the EERI researchers are looking for wineries to tour and document lessons learned from the earthquake.  Research opportunities include both wineries that have suffered significant damage and those that are in the affected region that suffered little to no damage.  There is value from an engineering perspective to observe both conditions.

Mr. Marrow’s winery research work started with an undergraduate seismic research project at Cal Poly San Luis Obispo in the Architectural Engineering program.  The Cal Poly team toured hundreds of wineries and conducted physical testing of a ½-scale wine barrel stack using a pneumatic earthquake “shake table”.  The project received donations from many wineries and vintner groups throughout the State, all interested in seeing this much-needed research through.

The primary focus of the research was the seismic performance of wine barrel stacks on portable steel barrel racks.  They also studied other seismically vulnerable systems, including stainless steel tank performance, stacked case goods, equipment and building performance.  The research was, and still is, entirely not for profit and received collective funding from hundreds of wineries, including Kendall Jackson, Robert Mondavi, and E&J Gallo.

The research was taken to the next level at UC Berkeley in 1999 and 2000.  Marrow continued the research with full scale earthquake shake table studies of the barrel stacks, both the two-barrel and four-barrel configurations, with stacks of all heights.

The shake table tests demonstrated the two-barrel system had a propensity for collapse under even moderate ground shaking.  The four-barrel rack exhibited exceptional performance and stability in comparison to the two-barrel rack.  Immediately after the completion of the Berkeley laboratory studies the M5.2 2000 Yountville earthquake hit.  It provided a timely opportunity to observe real life damage and compare the findings with the results from the lab testing.  Marrow investigated a number of facilities on the east and south sides of Napa.  Stacks of two-barrel racks collapsed just as we saw in the controlled shake table testing at Berkeley.  This same behavior and vulnerability has been documented over the last day by the photos that have been posted on internet news and social media sources.

Marrow performed further post-earthquake reconnaissance after the 2003 San Simeon earthquake that damaged wineries in the Paso Robles and Templeton regions.  The researchers observed the same damage patterns with the two-barrel rack and resilience of the four-barrel rack.

This South Napa earthquake is well-placed and of great enough magnitude to provide the research team opportunity to document damage in the lower valley areas and Carneros.  They would like to draw off the lessons learned already and see if the damage patterns are consistent with past earthquakes.

The research team is requesting wineries to provide opportunities to observe the following:

  • Wine barrel storage on steel racks and in pyramid configuration above ground and in caves
  • Pallet storage
  • Stainless steel tanks, anchored and unanchored
  • Building performance, especially older warehouse buildings (concrete tilt-up construction and masonry construction)
  • Process equipment including fixed piping and wash facilities

Please reach out to Mr. Marrow directly to coordinate a visit to your wine production facility.  All observations and documentation will remain confidential.  The opportune time to assess the damage is Monday and Tuesday, prior to completion of cleanup.

Mr. Marrow’s contact information is below.  He can be reached via email and mobile phone throughout the week of August 25, 2014.

Joshua M. Marrow, P.E. (CA)


Technical Director | Structural Engineering Group

Partner Engineering and Science, Inc.
111 Pine Street, Suite 1750, San Francisco, CA 94111
T: (415) 704-4022 | F: (415) 952-9421 | C: (415) 656-9325


Joshua Marrow Bio:  Mr. Marrow has been working in the field of structural engineering and earthquake risk management of over 17 years.  He is a Principal with Partner Engineering and Science, Inc., a nationally ranked real estate due diligence, engineering and environmental science firm headquartered in Torrance, California.  He holds a B.S. in Architectural Engineering from Cal Poly San Luis Obispo and an M.S. in Structural Engineering and Mechanics from UC Berkeley.