By Dr. Robert Thorson
The deadly landslide in La Conchita, Calif., was a study in contrast to the Indian Ocean tsunami. Though many of the scenes were familiar — broken homes (literally), body bags, human grief and explicit television coverage — there was one important difference.
Either most tsunami victims were ignorant of what was to come or their governments lacked the resources to help them. The opposite was true in California, where most victims were well informed of the landslide hazard — there were even posted warning signs — but refused the advice of experts and local governments to site their homes elsewhere.
When geologists point out the landslide elephant in the room, they are often accused of being as clinically unfeeling and as cold- hearted as the stones and mud they study. I am truly sorry for individuals who suffered personal grief, especially those involving the deaths of children. But I’m extremely frustrated with a legal system that allows private property owners to live wherever they please, even in this no-brainer case of slope instability, simply because their housing lots were grandfathered in before the deadly situation was fully revealed.
Between landslide events, La Conchita residents benefit from the proximity of the Pacific Ocean and splendid views that steep slopes provide. But when an event happens, it is the public who pays the costs of emergency services, engineering restorations and higher insurance rates. Effectively, we are subsidizing beach access and endangering children simultaneously. How legal is that?
The United States and California governments have invested heavily in landslide mapping and control. The rules of this game haven’t changed much since I mapped slope hazards for the U.S. Geological Survey in 1975. Since then, a generation of geology students has examined the Ventura County coast as a case study of where not to build, owing to the combination of steep slopes, wet, clay-rich soils, rapid tectonic uplift, severe gullying and frequent earthquakes.
Landslide management has many faces. At the scales of districts, cities, counties and states, panning professionals work to ensure that growth, needs and resources are well coordinated; their MO (modus operandi) is to anticipate and plan. Emergency response professionals make sure that when disaster strikes, those in urgent need get help; their MO is to wait and react. At the scale of private property, engineers work to identify any hazard and mitigate it; their MO is to identify and control. Geologists map soil properties, rock type, drainage and active earth processes; their MO is to reconstruct the history of the land and predict what will come. One other profession that is invested in saving lives from landslides is education. Teachers teach that what you know may save your life; their MO is to share what they know and hope for the best.
Who failed the La Conchita residents? Were the geologists, engineers, emergency responders, community planners or earth science teachers culpable? I think not. Like smokers who refuse to quit a deadly pleasure, there is probably no one to blame for the La Conchita disaster except the homeowners themselves, or those who suggested they live there. The La Conchita homeowners willingly chose to live in the barrel of a beautiful gun that shoots landslides instead of bullets, even though experts identified it as a gun. Public officials had warned that the gun was loaded, and teachers had pointed out that the safety lock was off. When the gun finally went off, the most informed residents simply accepted the loss (however tragic) as the price of living there — c’est la vie. The least informed acted surprised and blamed the gun. Some of those in the middle are hoping to sue their neighbors for pulling the trigger, or the government for not locking the gun in a cabinet.
I have two suggestions. First, give community governments more zoning power over natural hazards. Second, give earth science teachers a curriculum that emphasizes dynamic surface processes, rather than the cold hard facts about rocks.