Some surprises can be pleasing.

But when it comes to earthquakes and West Coast agriculture, including orchard crops, there’s nothing pleasant about the thought of the potential damage that could result, including to tree nut operations.

Halfway through 2019, this has already been a year of surprises for many California farmers. Coming on the heels of last year’s devastating wildfires, early fall freezes greeted the new year followed by exceptionally heavy rainstorms, a few but strong wind events and most recently, a series of frightening earthquakes and aftershocks in and around Kern County. Kern is one of the nation’s leading agricultural counties.

Residents in Ridgecrest, a desert community about 150 miles north of Los Angeles, have been cleaning up since a magnitude 6.4 temblor shook the region early July 4, and a 7.1 quake hit the same area on the evening of July 5. Dozens of smaller earthquakes have been felt since.

A shaking ground can easily damage irrigation systems and disturb deep tree root structures, although county Agricultural Commissioner Glenn Fankhauser said last week he hadn’t yet received any reports of agriculture-related damage.

Perhaps the truly disheartening aspect is that when it comes to seismic activity, it isn’t over until it’s over, and as of this writing, no one seems to know when it will end.

Caltech seismologist Dr. Lucy Jones reports aftershocks from the quakes could stretch well into the weeks ahead.

Earthquake risks for Golden State agriculture

According to the Food and Agriculture Organization (FAO) of the United Nations, natural disasters including earthquakes pose a serious risk to farming and livestock operations worldwide.

“An average of 3.5 million people are affected by earthquakes every year…although risks are normally associated with cities, the effects on the rural sector and farming communities can be devastating,” notes the FAO on their website.

Earthquakes can and have caused loss or injury to rural life, loss of crop yields and livestock, damage or destruction to irrigation systems and networks, and damages to stock tanks, and farm and ranch buildings.

In Haiti, after the 2010 earthquake that caused unprecedented damage, FAO provided seeds, hand tools and fertilizers to farming families throughout the country in order to help them re-establish agricultural production that had been lost or damaged. In the 2016 earthquake that struck Nepal, damage to livestock operations due to the earthquakes was estimated at $10.1 million USD, while damage to agriculture crops and production was $28.6 million USD.

Common damages include crop destruction in fields, destabilization of soils and ground support, damages to root systems, redistribution of aquifer resources or watersheds, disruption or destruction of irrigation systems, and loss of livestock.

For tree nut producers in both Pakistan and Iran, earthquakes have destroyed nut orchards in the past, greatly reducing production numbers and decreasing total acres of planted orchards.

California damage assessments

Serious earthquakes and agricultural operations are no exception to the rule. While there seems to be few historical records spotlighting specific agricultural losses from previous earthquakes, extensive damages this month in Kern County have been noted, including an estimated $70 million total damage including damages to buildings and roadways, while government and private sector assessments continue, little is known about the long-range effects the natural disaster may have for agriculture across the state.

In 2014, the Alfred E. Alquist Seismic Safety Commission for the State of California prepared a final report titled, “Earthquakes and California Agriculture: Where are the Vulnerabilities?” In that report, prepared by Scott J. Brandenberg of the University of California, Los Angeles, Daniel A. Sumner of the University of California’s Agricultural Issues Center and others, noted that Golden State agriculture is at serious risk to earthquake damage.

“California agriculture is especially vulnerable to damage from earthquakes for three main reasons. First, a substantial share of farm production and the associated marketing and processing activities are in regions particularly susceptible to seismic activity. Second, agriculture relies on public infrastructure, especially for power and transportation, that is likely to suffer disruptions following earthquakes, and redundancies are few in the rural systems,” the report summary notes.

Sumner confirmed by phone last week that in addition, a third risk is much of California agriculture is devoted to highly perishable commodities and farm and marketing activities, such as milking cows and processing milk or harvesting and shipping fresh vegetables that must be done without delay.

“In addition to these concerns, long term capital losses to the soil itself remain a concern in some regions,” he said.

Also, at risk is the California cattle industry, Sumner noted. Meloland Cattle Company was hit by a large earthquake in April 2010 that was centered just across the border in Mexico. The Meloland case study shows how dependent feedlot operations are on power grid, water and transportation infrastructure.

“Monterey County is the most important source of lettuce and other greens in the United States and an earthquake that knocks out power to cool storage facilities would be devastating to things like fresh produce and dairy operations. Large dairy herds cannot be hand milked so the loss of automatic milking systems could also cause major economic losses and threaten herd health,” Sumner said.

The study is available online at this link.

In yet another West Coast study, the shaking on areas with land reclamation increases the liquefaction potential and ground failure when loose or water-saturated soils shake.

If an earthquake should rattle the Central and Northern Valleys, there is also some concern over the stability of levees in Northern California that form the Sacramento-San Joaquin Delta, the hub of the state’s water system that provides water to about 25 million Californians and to millions of acres of agriculture in the region.

California’s valuable tree nut industry could also be vulnerable in the event of a major earthquake.

“In addition to the potential risk for direct tree loss [in a tree nut orchard] and damages to a root system in a major earthquake [near the orchard], potential impacts to irrigation systems could be a major problem. We have pressurized irrigation systems with rigid piping in California in addition to other types of irrigation systems and our dependency on water wells is also critical. Any type of disruption in irrigation systems, especially when it’s needed the most, could be a major concern,” explained Luke Milliron, Area Sustainable Orchard Systems Advisor in Butte County.

He said fortunately there has not been a major earthquake in his region since he became an advisor and he was unfamiliar with any research or studies conducted on the topic. But he said he believes it would be reasonable to consider the possibility damages or disruptions could occur if a major earthquake were to directly hit tree nut country.

He said he is so far unaware of any agricultural damages that may have been caused in the most recent round of earthquakes and tremors as those occurred far from his geographic area. Assessments are still underway.

“Earthquakes, they are something we have to think about,” he added.

Natural disasters, including deadly earthquakes, can be devastating to human life and can and do affect the socio-economic stability of life regardless where they strike. Agricultural operations are far from immune from such major problems – food for our thoughts in a year of disasters large and small. 

Additional Resources

Earthquake Country Alliance

California Institute of Technology Seismology Laboratory

Latest USGS Earthquake Event Map

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