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Tsunami Messaging Project


Participants on this webinar are listed at the bottom of this page.

These are notes following the webinar-enabled discussion held February 6, 2014, about tsunami terms. More notes from a lively discussion appear below.

Tsunami Messaging Project – 02/06/2014

Notes from the discussion of February 6, 2014

Christina Zarcadoolas, a professor from Columbia University, reminded us that messages relaying complex, technical information, are best written for public audiences when written with these cautions in mind:

* use shorter sentences.
* limit number of relative phrases and clauses.
* use active voice.
* line length 7-9 words.

The assembled group began discussing tsunami terms found on this wiki page.

General term–tsunami

Local tsunami has a distinctly different nature to it.

Terms like “far-field,” “distant,” or “ocean-wide” introduce confusion.

In Oregon, they use “distant” and “local” tsunami terms. These are important because they are two different hazards.

The term “distant” and “local” tsunami seem to be inherently understandable.

Introduces question about where do you draw the line between a distant and a local tsunami?

“Distant source” or “local source” tsunami. Perhaps this is handled within the definition. But it does make it clearer for the general public.

Terms and definitions under review:

A distant source tsunami is capable of widespread destruction, not only in the immediate region of its generation but across an entire ocean. These tsunamis are usually generated by large magnitude earthquakes. Also called “teletsunami”, “far-field tsunami” or “distant tsunami.”

A distant source tsunami is capable of widespread destruction near its source and across the ocean. A large magnitude earthquake is usually the cause of a distant tsunami. Also called “teletsunami”, “far-field tsunami” or “distant tsunami.”

A tsunami can cause widespread destruction. The destruction can be in the immediate area of the earthquake that generates a tsunami.

Ongoing comments from discussion:

A distant source tsunami has public safety implications. You won't feel the earthquake if it happens on the other side of the ocean.

Other terms to consider in this list–

* great earthquake

* large magnitude earthquake

* Regional source tsunami – travel time within 1 - 3 hours, such as within the Caribbean Sea. (You may or may not feel it.) A tsunami that falls between a distant source and a local source tsunami.

Consider using all three terms: Local source, Regional source, Distant source

We need to keep in consideration of where we are relative to the event that causes the tsunami.

Next terms for discussion:

METEOTSUNAMI – A tsunami caused by weather. Much more discussion is required before going further with this.

Amplitude is a term that comes out in the warning messages, so we should define this term.

Amplitude is the deviation between mean sea level to the wave height.

Wave height: The vertical distance between the wave peak and adjacent trough. Need to include in definition how “wave height” is understood by the public on the shore. Am I high enough?

Magnitude: a different term from amplitude. Related to earthquakes, not tsunamis. We should explain this.

Runup: an important concept.


Think about what terms are on the list that we don't need to include (considering general public is the audience.)

Think about what terms are not on the list that should be.

Terms that should remain on the list.

02/06/2014 webinar participants

Amanda Admire Eureka CA Redwood Coast Tsunami Work Group
Sam Albanese Anchorage AK NWSFO Anchorage
Nicolas Arcos Honolulu HI ITIC
Melinda Bailey Fort Worth TX NWS Southern Region
Jaye Compton Camp Murray WA Washington Emergency Management
Nicolas Hippisley-Coxe Los Angeles CA American Red Cross
Donna Hughes Crescent City CA Redwood Coast Tsunami Work Group
Rocky Lopes Silver Spring MD NWS HQ Tsunami Program
Jeff Lorens Salt Lake City UT NWS Western Region
Sue Perry Pasadena CA USGS SAFRR Program
Cindi Preller Anchorage AK NWS Alaska Region
Cindy Pridmore Sacramento CA California Geological Survey
Christa Rabenold Silver Spring MD NWS HQ Tsunami Program
Althea Rizzo Salem OR OEM
Justin Van Es Pearl Harbor HI Joint Typhoon Warning Center
Wendy Vaughon New York NY Columbia University
Christa von Hillebrandt Mayaguez PR NWS Caribbean Tsunami Warning Program
Brynne Walker Camp Murray WA Washington Emergency Management
Walt Zaleski Fort Worth TX NWS Southern Region
Christina Zarcadoolas New York NY Columbia University


Jeff Lorens, 2014/02/07 15:13 Here's my thoughts on terms to keep/add/drop: Types of tsunami: Distant, Local, Regional, Meteotsunami (add) Tsunami Terms: Amplitude, Bore, Inundation, Initial Wave (in lieu of “leading wave”), Wave Height, Wave Period, Wave Length (all specific to tsunami), trough, crest, tsunami debris (add), current (applied to tsunamis), time of initial (wave) arrival, resonance, runup, seiche, source, water level, tsunamigenic, recede (or recession) Earthquake Terms: Magnitude, epicenter, earthquake depth, subduction zone, strike-slip fault

Amanda Admire, 2014/02/25 18:14 Sorry for the delay in posting this info. I agree with Jeff that tsunami debris and tsunami currents are important terms to include here since they are in the media during and post event. Below are the terms I think should be kept or added to the list of terms: Types of tsunamis: local, regional, distant, meteotsunami Tsunami terms: amplitude, bore, inundation, inundation distance, inundation height/tsunami height/maximum water level (based on the definitions, I believe these are synonymous), inundation line, leading wave, propagation, recession/draw-down, harbor resonance, runup, seiche, source, travel time and initial arrival, tsunamigenic, wave crest, wave trough, tsunami wave height, tsunami wave period, tsunami wavelength, tsunami currents, tsunami debris Earthquake terms: epicenter, intensity, magnitude, subduction zone, strike-slip fault, reverse fault, normal fault

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messagenotes02062014.txt · Last modified: 2014/05/13 14:02 by christa