today
8:30 a.m. Audubon Society Field Trip See Event Description
read >9 a.m. Arcata Farmers' Market Arcata Plaza
read >9:30 a.m. Discovery Walk: Unknown Waterfront See Event Description
read >9:30 a.m. Manila Dunes Restoration Manila Community Center
read >10 a.m. Manila Dunes Guided Walk Manila Community Center
read >10 a.m. Library Book Sale Humboldt County Library
read >10 a.m. Dia de los Muertos and Mexican Folk Art Sale Private Eureka home
read >10 a.m. Final Arcata Farmer's Market Arcata Farmers' Market (off the plaza)
read >11 a.m. Donlin Foreman Dance Workshop Dell'Arte
read >2 p.m. Humboldt Coastal Nature Center Draft Trails Plan Walk Stamps House
read >5 p.m. Bati Zado and Show Redwood Raks World Dance Studio
read >6 p.m. The Tumbleweeds Chapala Cafe
read >6 p.m. Ali Chaudhary (jazz duo) Libation
read >6:30 p.m. Not Evil, Just Wrong Humboldt Area Foundation
read >7 p.m. Guitar Stan (country) Old Town Coffee & Chocolates
read >8 p.m. Guitar Orchestra of Barcelona Arkley Center for the Performing Arts
read >8 p.m. Stones in His Pockets Arcata Playhouse
read >8 p.m. A Christmas Carol North Coast Repertory Theater
read >8 p.m. Donna Landry Swing Dance Moose Lodge
read >8 p.m. North Coast Wind Ensemble Fulkerson Recital Hall at HSU
read >8:30 p.m. The Last Minute Men (international) Cafe Mokka
read >9 p.m. Ian McFeron Band (folk rock) Six Rivers Brewery
read >9 p.m. The Michael Paul Band WAVE @ blue lake casino
read >9 p.m. The Generatorz (classic rock) Central Station Cocktail Lounge
read >9 p.m. Taxi Bear River Casino
read >9 p.m. VJ Itchie Fingaz Pearl Lounge
read >9 p.m. Jack Ruby Presents + Blue Street + Acufunkture (DIY rock) Jambalaya
read >9 p.m. 2nd Annual Scorpio Bash The Red Fox Tavern
read >10 p.m. Music by DJ Sidelines
read >10 p.m. DJ Icy Hot Aunty Mo's Lounge
read >10 p.m. Jemimah Puddleduck (rock) Humboldt Brews
read >10 p.m. White Manna + Midday Veil + The King Salmon Duo (rock) Jambalaya
read >11 p.m. Radio Moscow (psychadelic blues) + Mosquito Bandito (one-man surf/garage) The Alibi Lounge and Restaurant
read >previous columns
March 13, 2008
In Formation
The V-formations of honking Aleutian Cackling Geese that decorate our ...
read >March 6, 2008
The Ins and Outs of Tides
The Moon's gravity decreases with distance, so it pulls unequally ...
read >
Photos
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Tsunnami range simulation. Courtesy USGS.
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Tsunami travel times. Diagram by Don Garlick
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Plot of wave height verses water depth. Diagram by Don Garlick.
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Graph of tide guage at Sitka, Alaska. Diagram by Don Garlick.
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Diagram showing how waves break and tsunamis surge. Diagram by Don Garlick.
Tsunami Terrors
By Don Garlick
Understanding the nature of tsunamis could save your life. They are usually caused by large earthquakes, coastal or submarine. You could expect timely warning of a tsunami generated thousands of miles away, but if our local Cascadia Megathrust is the culprit, the violent shaking would be your cue to head for the highest ground reachable within a few minutes.
Tsunami waves have wavelengths of a few hundred kilometers and travel at almost 800 km per hour in deep water. The first image shows a simulation, by the USGS, of waves 4 hours after their creation by the Magnitude 9 Cascadia quake of Jan 26, 1700, dated by Japanese records. The map shows the propagation of such a tsunami at hourly intervals. It would reach Hawaii in five hours. One generated in Hawaii would reach us in five hours.
The plot of wave height verses water depth explains how a wave may be imperceptible at sea but damaging on the coast. Additionally, long-wavelength waves are more likely to surge than to break. A tide gage at Sitka, 1,000 km from the 1964 Alaskan epicenter, reveals the long duration of tsunami waves.
On March 26, at about 10:30 a.m., there will be a test of NOAA's Tsunami Warning System. Visit www.wrh.noaa.gov/eka/misc/tsunamitest.php for more information.
I thank Prof. Lori Dengler for her input.
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