Tsunami Warning System: Response Criteria, Message Types, and Graphical Products

1. U. Washington Tsunami Certificate ProgramCourse 2:Tsunami Warning SystemsSession 10Tsunami Warning MessagesJuly 29, 2007 8:30-9:20am Page 1

2. Outline • Response criteria • Basis • Example • Flow charts • Message Types • Message Content • Graphical Products • WMO standards Page 2

3. Response Criteria • Initial TWC response must be as quick as possible • Base initial response on seismic processing and well-planned procedures • Especially critical for regional events • Set procedures for all possible earthquake scenarios • Supplemental message procedures can not be so scripted • Too many possible situations • More time to contemplate decisions • Analyst judgment comes into play more as the event proceeds • Response criteria normally set conservatively • Infrequent events • Much uncertainty – especially just after origin time Page 3

4. Response Criteria • How to best convey the response criteria to analysts? • Criteria clearly displayed in center • Run simulations regularly • Set up a practice machine • Set up an automatic prompt (next slide) Page 4

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6. Response Criteria • Basis for criteria • Historical data • Tsunami Models • Especially important where no historical data exists • For example, Gulf of Mexico • Tectonic setting • Comparative analysis • If there is no historic data, can the area be compared to other regions with history? • Geologic setting • Landslide potential? Page 6

7. Tsunamis impacting WCATWC AOR Page 7

8. Tsunamis impacting WCATWC AOR Page 8

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11. Message Types • Most countries have their own definitions for warning, watch, etc. • There is no international standard for definitions • U.S. just re-defined its definitions • Messages must be understandable to primary recipients Page 11

12. Message Types - Warning • Tsunami Warning: • A Tsunami Warning is issued by the Tsunami Warning Centers when a potential tsunami with significant widespread inundation is imminent or expected.  Warnings alert citizens that widespread, dangerous coastal flooding accompanied by powerful currents is possible and may continue for several hours after arrival of the initial wave. Warnings also alert emergency management officials to take action for the entire tsunami hazard zone.  Appropriate actions to be taken by local officials may include the evacuation of low-lying coastal areas, and the repositioning of ships to deep waters when there is time to safely do so.  Warnings may be updated, adjusted geographically, downgraded, or canceled.  To provide the earliest possible alert, initial warnings are normally based only on seismic information. • Warning means big wave could come – head to high ground Page 12

13. Message Types - Advisory • Tsunami Advisory: • A Tsunami Advisory is issued by the Tsunami Warning Centers due to the threat of a potential tsunami which may produce strong currents or waves dangerous to those in or near the water.  Coastal regions historically prone to damage due to strong currents induced by tsunamis are at the greatest risk. The threat may continue for several hours after the initial wave arrival, but significant widespread inundation is not expected for areas under an Advisory.  Appropriate actions to be taken by local officials may include closing beaches and evacuating harbors and marinas, and the repositioning of ships to deep waters when there is time to safely do so.  Advisories are normally updated to continue the Advisory, expand/contract affected areas, upgrade to a Warning, or cancel the Advisory.  • Advisory means strong surges possible, but no inundation expected – Get off the beach Page 13

14. Message Types - Watch • Tsunami Watch: • A Tsunami Watch is issued by the Tsunami Warning Centers to alert emergency management officials and coastal citizens of an event which may later impact the Watch area. The Watch area may be upgraded to a Warning or Advisory (or canceled) based on updated information and analysis.  Therefore, emergency management officials and coastal citizens should prepare to take action.  Watches are normally issued based on seismic information without confirmation that a destructive tsunami is underway.  • Watch means that a wave may have been generated that could impact your area – stay tuned Page 14

15. Message Types - Information • Information Statement: • An Information Statement is issued to inform emergency management officials and coastal citizens that an earthquake has occurred.  In most cases, Information Statements indicate there is no threat of a destructive tsunami affecting the issuing Tsunami Warning Center’s Area of Responsibility and they are issued to prevent unnecessary evacuations as the earthquake may have been felt in coastal areas.  An Information Statement may, in appropriate situations, caution about the possibility of destructive local tsunamis. Information Statements may be re-issued with additional information, though normally these messages are not updated. However, a Watch, Advisory or Warning may be issued for the area, if necessary, after analysis and/or updated information becomes available. • Information generally means that no danger is expected – enjoy the beach Page 15

16. Message Content • Exercise – What should be in the message??? Page 16

17. Message Creation • Not enough time to create messages on the fly • Must be automatically created based on some control information • Source location • Magnitude • Tsunami arrival times at points of interest • Observed wave heights • Evaluation options specified by analyst • Pre-defined criteria • Analyst must have ability to modify message • Language • Difficult to issue in other languages • Can be done, but hard to modify Page 17

18. Message Content • Basic content of tsunami messages: • Header (WMO standard) • Headline (who is in a warning) • Evaluation (impact threat) • Observed wave heights • Earthquake information • Tsunami arrival times • Background information (watch/warning definitions) • Follow-up message information • Public messages • Easier to read Page 18

19. Message Content • Supplemental messages: • Flow charts can provide guidance for supplemental bulletins • Upgrades to warning • Downgrade to Advisory • Cancellation • All clear • Still minor danger • Final Supplement • See web site for example messages Page 19

20. Messages – Graphical Products • Break out here and look at WCATWC and PTWC web sites • Future improvements: • Max wave height (energy directionality) maps • Telescoping warning/advisory/watch maps • Inundation maps for certain sites Page 20

21. WMO product headers (PTWC) Page 21

22. Message Example • WEPA43 PAAQ 230944 • TIBWCA • TSUNAMI INFORMATION STATEMENT NUMBER 1 • NWS WEST COAST/ALASKA TSUNAMI WARNING CENTER PALMER AK • 244 AM PDT MON OCT 23 2006 • ...THIS TSUNAMI INFORMATION STATEMENT IS FOR ALASKA/ BRITISH COLUMBIA/ WASHINGTON/ OREGON AND CALIFORNIA ONLY... • NO - REPEAT NO - WATCH OR WARNING IS IN EFFECT FOR THE STATES AND PROVINCES LISTED ABOVE. • EVALUATION • BASED ON MAGNITUDE AND HISTORIC TSUNAMI INFORMATION THE EARTHQUAKE WAS NOT SUFFICIENT TO GENERATE A TSUNAMI DAMAGING TO CALIFORNIA/ OREGON/ WASHINGTON/ BRITISH COLUMBIA OR ALASKA. IN COASTAL AREAS OF INTENSE SHAKING LOCALLY GENERATED TSUNAMIS CAN BE TRIGGERED BY UNDERWATER LANDSLIDES. • PRELIMINARY EARTHQUAKE PARAMETERS • MAGNITUDE - 6.8 • TIME - 0140 AKDT OCT 23 2006 • 0240 PDT OCT 23 2006 • 0940 UTC OCT 23 2006 • LOCATION - 16.4 NORTH 102.5 WEST - OFF COAST OF GUERRERO MEXICO • DEPTH - 21 MILES Page 22

23. Tsunami Warning Messages - Summary • Initial response must be pre-planned for all possible scenarios. • Response criteria can become complex over large AORs. Information must be presented in a clear way to the analysts. • Message types and meanings vary between countries and there is no international standard. In the U.S.: • Warning -> Evacuate to max expected limit • Advisory -> Move away from the beach • Watch -> Stay tuned for more information • Information -> No danger • Messages must be composed automatically based on source parameters. Page 23