Note: September is National Preparedness Month. Follow this year’s campaign on Twitter by searching for the #NatlPrep #BeReady or #PrepMonth hashtags.
This month, as part of #NPM23, I’ll be rerunning some updated preparedness essays, along with some new ones
#17,679
Based on the GSHAP map of global seismic hazard zones (above), few people living in North Africa would have expected a devastating earthquake to strike Morocco last week, killing and injuring thousands of people. While the levels of risk may vary, much of the world's population live in a seismically active area.
In 2006 the USGS calculated that earthquakes posed a significant risk to 75 million Americans living in 39 States.
Since then, populations have changed and/or shifted and ongoing research has uncovered new seismic risks (see USGS: Updated U.S. Seismic Risk Hazard Maps), providing geologists with a better understanding of the extent of ground shaking from these quakes.
A new study, published in 2015 in the journal Earthquake Spectra, nearly doubled – to 143 million - the number of Americans who live or work in areas susceptible to potentially damaging ground shaking.
The New Madrid Seismic Zone (NMSZ), the Pacific Northwest (Cascadia fault), coastal South Carolina, Alaska and Hawaii, and even New York City and parts of New England are at risk of seeing significant seismic activity.
The Pacific, Gulf, and Atlantic coastlines are also susceptible to tsunamis generated from from both local and distant earthquakes (see East Coast Tsunami Threats). For Americans, there is better than a 50-50 chance that they live in an area that is at risk of some seismically induced disaster.
Additionally, there are nearly a dozen `very high risk' volcanoes in the continental US (4 in Washington, 4 in Oregon & 3 in California), along dozens of `lesser' threats. While earthquake damage is generally localized, volcanic eruptions can affect property and populations thousands of miles away.
Over the past 100+ years the United States (excluding Alaska & Hawaii) has experienced a `seismic drought', with relatively few big quakes or volcanic eruptions. As a result, most people assume the next `big one' won't happen in their lifetimes.
In 2019 the SSA (Seismological Society of America) held their annual meeting, and a study was presented that concludes that California's recent lack of major quakes has no precedent in the past 1000 years.
The Current Unlikely Earthquake Hiatus at California’s Transform Boundary Paleoseismic Sites
Glenn P. Biasi, Katherine M. Scharer
Seismological Research Letters (2019) 90 (3): 1168-1176.
https://doi.org/10.1785/0220180244
ABSTRACT
Paleoseismic and historical earthquake records used to quantify earthquake recurrence rates can also be used to test the likelihood of seismically quiescent periods. At principal paleoseismic sites in California on the San Andreas, San Jacinto, Elsinore, and Hayward faults, no ground‐rupturing earthquake has occurred in the last 100 yr, yet this interval is about three times the average interearthquake period for the ensemble of sites.
(Continue . . . )California, they announced, has been in an earthquake drought for the past 100 years. One, that the SSA warns, is unlikely to continue. In a news release they wrote:
They agree that the next 100 years of California earthquakes along these faults could be a busy one. “If our work is correct,” Scharer and Biasi note, the next century isn’t going to be like the last one, but could more like the century that ended in 1918.”
- FEMA and the U.S. government conducted a huge drill seven years ago (see FEMA: Cascadia Rising 2016) involving 20,000 people from both the United States and Canada, in order to prepare for a catastrophic M9.0 quake & tsunami off the Pacific coast.
- And in 2011 – during the bicentennial of the four great New Madrid earthquakes of 1811-12 –FEMA and other federal agencies mounted the largest National Level Exercise (NLE) to that date, revolving around a catastrophic earthquake occurring in the New Madrid Seismic Zone (NMSZ) that would involve eight Central U.S. States.
- Perhaps least appreciated is the seismic history of South Carolina, which in 1886 was struck by an (Est. 7.3-7.6 magnitude) quake that devastated much of Charleston, South Carolina. Shaking was felt as far north as Boston, south to Cuba, and west as far as New Orleans.
Even if you don't live or work in the shake zone of one of the events, should a great quake strike any one of them, the economic and societal impacts could easily spread far beyond the damaged area.
Imagine an M8.0 New Madrid quake collapsing major bridges that cross the Mississippi river, buckling the Midwest's railroad tracks and interstate highways, and taking out the dozens of critical natural gas pipelines that snake through that region.
Imagine an M8.0 New Madrid quake collapsing major bridges that cross the Mississippi river, buckling the Midwest's railroad tracks and interstate highways, and taking out the dozens of critical natural gas pipelines that snake through that region.
A quake of that size could impact the transportation of food, the delivery of energy (power, gas, coal, etc.), the national power grid, and the nation's economy in ways we can only partially imagine.
While we can't prevent the next big quake from happening, we can prepare for it.
Working to improve earthquake awareness, preparation, and safety is Shakeout.org, which promotes yearly earthquake drills and education around the country (see A Whole Lotta Shakeouts Going On).
The third Thursday in October (Oct 19th in 2023) is International Shakeout Day, when dozens of states and countries practice earthquake safety. If you live in or near one of these seismically active areas, I would strongly urge you, your family, and your employees take part in these yearly drills.
But after the shaking stops, you'll have to find ways to cope with the aftermath.
While the government will send help, you could find yourself pretty much on your own for several days and living in less than comfortable conditions for weeks.
For starters - and as a bare minimum - every household should have a disaster plan, a good first aid kit (and the knowledge to use it), an emergency battery operated NWS weather radio, and emergency supplies to last a minimum of 72 hours during a disaster.
As the (above) graphic illustrates (see #NatlPrep: FEMA National Household Preparedness Survey), while we've seen some improvement over past few years, Americans still have a long way to go if we are to cultivate a culture of preparedness.
While 72 hours is an admirable start, I wouldn't feel comfortable with it. Here in the United States many agencies and organizations recommend that households work towards having a 10-to-14 day supply of food, water, and emergency supplies on hand.
As the (above) graphic illustrates (see #NatlPrep: FEMA National Household Preparedness Survey), while we've seen some improvement over past few years, Americans still have a long way to go if we are to cultivate a culture of preparedness.
For more on earthquake preparedness, both here in the United States, and around the world, you may wish to revisit:
Japan's Earthquake Preparedness Messaging - Tokyo's X Day
USGS: Induced Earthquakes Raise Chances of Damaging Shaking in 2016
California Quakes : Concrete Concerns
Estimating The Economic Impact Of A San Andreas Quake
USGS/OGS Joint Statement On Increased Earthquake Threat To Oklahoma
