Check Out These Interesting Earthquake Facts

Here are a few interesting earthquake facts shared through the Earthquake Hazards Program of the United States Geological Service (USGS):

1.  The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, Alaska on Good Friday, March 28, 1964.

2.  The largest recorded earthquake in the world was a magnitude 9.5 in Chile on May 22, 1960.

3.  Alaska is the most earthquake-prone state and one of the most seismically active regions in the world.  Alaska experiences a magnitude 7 earthquake almost every year, and a magnitude 8 or greater earthquake on average every 14 years.

4.  From 1975 to 1995 there were only 4 states that did not have any earthquakes:  Florida, Iowa, North Dakota and Wisconsin.

5.  Florida and North Dakota have the smallest number of earthquakes in the United States.

6.  The magnitude of an earthquake is a measured value of the earthquake size.  The magnitude is the same no matter where you are, or how strong or weak the shaking was in various locations.  The intensity of an earthquake is a measure of the shaking created by the earthquake, and this value does vary with location.

7.  Most earthquakes occur at depths of less than 50 miles (80 km) from the Earth’s surface.

8.  The hypocenter of an earthquake is the location beneath the earth’s surface where the rupture of the fault begins.  The epicenter of an earthquake is the location directly above the hypocenter of the surface of the earth.

9.  A seiche (pronounced SAYSH) is what happens in a swimming pool during and after an earthquake.  It is “an internal wave oscillating in a body of water” or, in other words, it is the sloshing of the water in a swimming pool, or any body of water, caused by the ground shaking in an earthquake.  It may continue for a few moments or hours, long after the generating force is gone.  A seiche can also be caused by wind or tides.

10. The swimming pool at the University of Arizona in Tucson lost water from a seiche (sloshing) caused by the 1985 Magnitude 8.1 Michoacan, Mexico earthquake 1240 miles (2000 km) away.

Retrofitting Substandard Basement Foundations: Can We Afford It?

Quite often, installing foundation anchoring brackets in the basements of older homes is compromised by deteriorating concrete.  These older foundations deteriorate for a variety reasons, but the most common cause stems from poor cement and sand mixtures.  During a significant seismic event, lateral forces can cause disintegration of these substandard foundations.  There are many workarounds for this condition, most of them carrying huge price tags.  Fault Line’s professional engineering staff has devised an affordable solution to bridge the gap between inadequate foundations and monumental rehabilitation costs. Expertly engineered wood frame sheer panels are installed on proper footings in key load transfer sections adjacent to the concrete foundation. 

WN #1                         WN #2                        WN #3

We invite you to call us today to schedule an appointment to evaluate your basement foundation anchoring project.  Your safety (and guarding your wallet) is our first priority.

Cascadia Study Complete – Findings Show Earthquake Risks VERY Real

Cascadia Study Complete – Findings Show Earthquake Risks VERY Real

Over the past 13 years, researchers from Oregon State University’s College of Earth, Ocean and Atmospheric Sciences (CEOAS) have been analyzing the Cascadia Subduction Zone, a region off the Northwest coast where the Juan de Fuca tectonic plate is being subducted beneath the continent.

Chris Goldfinger, a professor at OSU’s CEOAS, is the lead author of the study, which took 4 years to complete.  The 184-page report is the most comprehensive overview ever written of the Cascadia Subduction Zone.  The report itself, fairly technical in nature, confirms that the region has had numerous earthquakes over the past 10,000 years.  It suggests that the southern Oregon coast may be most vulnerable based on recurrence frequency.  The study concludes that there is a 40 percent chance of a major earthquake in the Coos Bay, Oregon region during the next 50 years, and that the quake could approach the intensity of the Tohoku quake that devastated Japan in March of 2011.

“Over the past 10,000 years, there have been 19 earthquakes that extended along most of the margin, stretching from southern Vancouver Island to the Oregon-California border,” Goldfinger noted.  “These would typically be of a magnitude from about 8.7 to 9.2—really huge earthquakes.  We’ve also determined that there have been 22 additional earthquakes that involved just the southern end of the fault,” he added.  “We are assuming that these are slightly smaller—more like 8.0—but not necessarily.  They were still very large earthquakes that if they happened today could have a devastating impact.”

The clock is ticking on when a major earthquake will next strike, said Jay Patton, an OSU doctoral student and co-author of the study.  “By the year 2060, if we have not had an earthquake, we will have exceeded 85 percent of all the known intervals of earthquake recurrence in 10,000 years,” Patton said.  “The interval between earthquakes ranges from a few decades to thousands of years.  But we already have exceeded about three-fourths of them.”

The last mega-earthquake to strike the Pacific Northwest occurred on January 26, 1700.  Researchers know this, Goldfinger said, because written records in Japan document how an ensuing tsunami destroyed that year’s rice crop stored in warehouses.

Patrick Corcoran, a hazards outreach specialist with OSU’s Sea Grant Extension program, says West Coast residents need to align their behavior with this kind of research.  “Now that we understand our vulnerability to mega-quakes and tsunamis, we need to develop a culture that is prepared at a level commensurate with the risk,” Corcoran said.  “Unlike Japan, which has frequent earthquakes and thus is more culturally prepared for them, we in the Pacific Northwest have not had a mega-quake since European settlement.  And since we have no culture of earthquakes, we have no culture of preparedness.  The research, though, is compelling,” he added.  “It clearly shows that our region has a long history of past events, and the single most important thing we can do is begin ‘expecting’ a mega-quake, then we can’t help but start preparing for it.”

For additional information regarding preparation of the Cascadia study, go to: http://oregonstate.edu/ua/ncs/archives/2012/jul/13-year-cascadia-study-complete-%E2%80%93-and-earthquake-risk-looms-large

To view the complete study, go to:  http://pubs.usgs.gov/pp/pp1661f/

For more information about the OregonStateUniversity’s Collegeof Earth, Ocean and Atmospheric Sciences, visit: www.ceoas.oregonstate.edu

Oregon HazVu Web Tool

Ricardo, our structural engineer, recently learned of a web tool created by the Oregon Department of Geology and Mineral Industries.  This tool allows you to enter an address and see which geohazards may affect that location, including a Cascadia earthquake and tsunami, volcanoes and landslides.  Oregon HazVu also shows those areas with active faults, earthquake soft soil hazards and expected shaking.  You can check out this online tool by going to www.OregonGeology.org/sub/hazvu.

The launching of this viewer was timed to coincide with The Great Oregon Shakeout, a statewide “Drop, Cover, and Hold On” drill designed to encourage people to protect themselves during an earthquake at work, school and home.  Further details are available at www.Shakeout.org/Oregon.

 

Building Your Emergency Disaster Kit

A disaster or emergency supply kit is simply a collection of basic items your household may need in the event of an emergency.  Try to assemble your kit well in advance of an emergency.  You may have to evacuate at a moment’s notice and take essentials with you.  There probably will not be time to search for the supplies you need or to shop for them. 

We may need to survive on our own after an emergency.  This means having our own food, water and supplies in sufficient quantity to last for at least 3 days.  Local officials and relief workers will be on the scene after a disaster, but they cannot reach everyone immediately.  Additionally, basic services such as electricity, gas, water, sewage treatment and telephones may be cut off for days–or even longer.  Emergency supply kits should contain items to help us manage during these outages.

Keep your kit in a designated place and have it ready in case you have to leave your home quickly.  Make sure all family members know where the kit is kept.

Basic Disaster Supplies Kit

Basic emergency supply kits could include the following recommended items: 

WATER:  One gallon of water per person per day for at least 3 days, for drinking and sanitation.

FOOD:  At least a 3-day supply of non-perishable food.  This supply could include:

   – Ready-to-eat canned meats, fruits, vegetables and a can opener

   – Protein or fruit bars

   – Dry cereal or granola

   – Peanut butter

   – Dried fruit

   – Nuts

   – Crackers

   – Canned juices

   – Non-perishable pasteurized milk

   – High-energy foods

   – Vitamins

   – Food for infants

   – Pet food and extra water

   – Comfort/stress foods

Battery-operated or hand-crank radio and a NOAA weather radio with tone alert; extra batteries for both

Flashlight and extra batteries

First aid kit

Whistle to signal for help

Dust mask to help filter contaminated air

Plastic sheeting and duct tape to shelter in place

Moist towelettes, garbage bags and plastic ties for personal sanitation

Wrench or pliers to turn off utilities

Local maps

Cell phone with chargers, inverter or solar charger

Additional Items to Consider Including in Your Kit:

Prescription meds and glasses

Infant formula and diapers

Cash or travelers checks and change

Sleeping bag or warm blanket for each person

Complete change of clothing, including a hat and gloves

Household chlorine bleach and medicine dropper.  When diluted 9 parts water to 1 part bleach, bleach can be used as a disinfectant.  It can be used to treat water by using 16 drops of regular household liquid bleach per gallon of water.  Do not use scented, color safe or bleaches with added cleaners.

Fire extinguisher

Matches in a waterproof container

Feminine supplies and personal hygiene items

Mess kits, paper cups, plates, paper towels and plastic utensils

Paper and pencil

Books, games, puzzles and other activities for children

For additional, detailed suggestions on preparing your emergency kit, visit FEMA’s website located at http://www.ready.gov/basic-disaster-supplies-kit.

Since we can’t know for sure when we’ll find ourselves in an emergency situation, it’s never too soon to start planning and preparing.  Begin to assemble your emergency disaster kit today.  You’ll feel really good once it’s done.

September 7th Earthquake Felt From Portland to Salem

Shortly before 10:00 pm on Friday, September 7th, the region known as Scotts Mills, Oregon, near Woodburn, was again shaken by an earthquake.  This crustal quake was on the same fault that carried the Spring Break quake of March, 1993.  That earthquake, measuring a magnitude 5.6, did some considerable damage to the area, including damage to the State Capitol building in Salem. Parts of the Capitol building were closed for repair for 2 years while the building was seismically retrofitted with additional concrete and steel bars.  This recent September quake, a magnitude 3.5, was not big enough to do any significant damage, but was felt from near Salem to just north of Portland.

Recent Tsunami Evacuation Drill in Coos Bay Rated a Big Success!

On May 31, 2012, three Oregon communities on the bay held their first tsunami evacuation drill, stirred to action by the 2011 earthquake and tsunami that devastated coastal towns in Japan.  Coos Bay Fire Chief Stan Gibson said the vivid TV images of last year’s tsunami in Japan have made people on the Oregon Coast take the possibility much more seriously than about 10 years ago, when new signs laying out tsunami evacuation routes were greeted with complaints that they would just scare the tourists.

The biggest threat to these communities is a megaquake from the Cascadia Subduction Zone, where two plates of the Earth’s crust butt together off the coast.  When they slip, they could send a 40-foot surge of water moving at the speed of a jetliner into the Oregon coast, Washington and Northern California.  After feeling the quake, people have about 20 minutes to reach higher ground.  Authorities advise them to walk, because roads could be impassable and power lines down.  Geologic evidence shows the zone jolts on average every 300 to 600 years, and the last one was 312 years ago.

More than 9,000 people participated in the Tsunami Evacuation Drill comprised of businesses, schools and organizations.  Several residents reported they simply discovered where high ground was and went as high as they could in 15 minutes.

 To view of a clip of the Coos Bay tsunami drill, visit http://coostsunami.org.

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