DRAFT - Tsunami Response Plan Playbook Santa Cruz Harbor Maritime Community

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Tobias Brooks
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DRAFT - Tsunami Response Plan Playbook Santa Cruz Harbor Maritime Community Page 1 Best to display on 11X17 paper Purpose and Use of this Real-time Tsunami Response Plan

It has been developed with assistance from the harbor by the California Tsunami Program and funding from FEMA.

The information within the playbook can also help the harbor develop tsunami mitigation strategies (other guidance is available for this).

First, it requires that the harbor fill out information about their harbor (see Background information on Page 2, and Playbook information on Pages 4-7); this should be

When a tsunami is occurring, follow the steps outlined on Page 2.

multiple sources, including the tsunami alert message from the National Tsunami Warning Center, the city or county emergency manager, and/or the National Weather Service,

1 DRAFT - Tsunami Response Plan Playbook Santa Cruz Harbor Maritime Community Page 1 Best to display on 11X17 paper Purpose and Use of this Real-time Tsunami Response Plan Playbook PURPOSE: This product will help the harbor prepare, plan, and respond to strong currents and damage from future tsunamis. It has been developed with assistance from the harbor by the California Tsunami Program and funding from FEMA. It is essential that harbor staff become familiar with the playbook before use. The information within the playbook can also help the harbor develop tsunami mitigation strategies (other guidance is available for this). USE: This playbook is designed to help the harbor with tsunami response activities by providing enhanced info about the tsunami based on specific inputs for the harbor. First, it requires that the harbor fill out information about their harbor (see Background information on Page 2, and Playbook information on Pages 4-7); this should be done when the Playbook is first received. The California Tsunami Program will work with the harbor to get this information. When a tsunami is occurring, follow the steps outlined on Page 2. The harbor master or emergency response manager should fill out information about the source earthquake and tsunami on Page 2; this information can be obtained from multiple sources, including the tsunami alert message from the National Tsunami Warning Center, the city or county emergency manager, and/or the National Weather Service, Regional Weather Forecast Office. Keep in mind that this information can change during the first hour or two after the earthquake occurs. Finally, compare the tsunami forecast amplitude (wave height) to the maximum tsunami amplitude on the scenario table on Page 3. Choose the scenario (Page 4-7) which best matches the forecast information. Follow the instructions on the page for that scenario. Each scenario Playbook may be accompanied by a digital file indicating the response and evacuation plans; this can be shared during an emergency with emergency responders in the field.

2 Background Information on Harbor Page 2 Table of Contents Tsunami Response Plan Playbooks Page 1: Purpose and Use of Maritime Tsunami Playbooks Page 2: Background Information on Harbor and Table of Contents Page 3: Quick Reference Page for Determining Real-Time Tsunami Response Activities Pages 4-5: General Tsunami Information (Alert Messages) Pages 6-9: Tsunami Response Scenario Playbook Plans Pages Page 10: Notable Historical Tsunamis and Tsunami Modeling Results Page 11: Plan for Safe Offshore Evacuation of Boats Page 12: Tsunami Evacuation Zone Map for Santa Cruz Area Explanation of FASTER Analytical Tool: To determine the full impact of the tsunami, other variables such as tidal and storm conditions must be considered. An analytical method has been created which incorporates important variables that will impact the ultimate tsunami flood level. The FASTER calculation, which will be provided by the local jurisdiction to the harbor during a tsunami event, is used on Page 3 to determine if piles will be overtopped and inundation of dry land will occur. The simplified components of the calculation are as follows: Background information (previously filled out by harbor): Harbor/Jurisdiction/Geographic Location: Height of shortest pilings above Mean Sea Level: Elevation of lowest land above Mean Sea Level: Areas of harbor previously damaged or showing potential for damage: Areas known to be safe in previous events and based on modeling: Distance offshore and time to reach 30 fathom (180 feet) depth (see Pg. 11): Background information on harbor: 1)Height of piles and land where inundation might occur. Useful for determining if the tsunami will overtop piles and if land inundation will occur. 2)Summary of areas of past tsunami damage and areas that will be safe during all tsunamis. 3)Offshore distance and time for ships to reach 30 fathoms. This has been determined a safe depth for vessels during all distant tsunamis.

Quick Reference Page for Determining Real-Time Tsunami Response Activities Page 3 NOTE: It is important to review all sections of this Playbook prior to using it during a tsunami emergency.

3 Quick Reference Page for Determining Real-Time Tsunami Response Activities Page 3 NOTE: It is important to review all sections of this Playbook prior to using it during a tsunami emergency. When a Tsunami Alert is issued, fill out the Quick Reference page below and follow steps on the right side of the page to determine response activities for the harbor: Step 1: Obtain information about earthquake and tsunami from National Tsunami Warning Center in Alaska, regional NOAA-Weather Forecast Office, and/or county emergency manager. (e.g. ) Event/Incident Name Earthquake location Earthquake magnitude Tsunami Alert level Forecasted tsunami amplitude/wave height (will be compared to Peak Amplitude in Step 2) Forecasted tsunami arrival time Highest projected tidal height (above Mean Sea Level) for first 5 hrs after arrival Ambient ocean/storm conditions for first 5 hrs after arrival Calculate/obtain FASTER tsunami run-up value in first 5 hours (see Page 2 for FASTER approach) Calculate/obtain FASTER tsunami run-up value at highest tide (see Page 2 for FASTER approach) Step 2: Compare and match forecasted tsunami amplitude/wave height in Step 1 to Peak Amplitude in the table. Refer to associated Playbook page to determine actions for securing vessels and repositioning ships away from areas of expected damage to safe areas within the harbor or offshore (Pg. 11) (modeled data in parentheses). STEP 1: Collect general tsunami information, used with table in Step 2 to determine appropriate actions to follow: 1) Earthquake location and magnitude. 2) Tsunami Alert level. 3) Forecast amplitude and arrival time provided by Warning Center. 4) Tidal and storm conditions provided by local Weather Forecast Office. 5) FASTER calculation, provided by WFO or county. STEP 2: Chose scenario/event from Step 1 that best matches tsunami information on the table: 1) Compare forecast amplitude/wave height from real event in Step 1 to peak amplitude column from historical events/ scenarios on table (highlighted in red box at left). 2) Find matching scenario in playbook. 3) Go to appropriate playbook page and follow instructions for response. 4) Each Playbook scenario may have digital maps or information available for sharing with people in the field or other offices. Step 3: Infrastructure considerations: Will the tsunami overtop harbor pilings? (compare FASTER run-up value to lowest pile height) Will the tsunami inundate dry land? (compare FASTER run-up value to lowest land elevation) STEP 3: Estimate of potential inundation of land and overtopping of piles: Helps estimate the potential and amount of inundation, and if piles will be overtopped. Land evacuation should be coordinated with city or county emergency manager.

4 General Tsunami Information for Maritime Communities Page 4 There are a number of TSUNAMI HAZARDS that could directly affect boats/boaters: Sudden water-level fluctuations Where boats and docks hit bottom (grounded) as water level drops Docks and boats could overtop piles as water level rises Strong and unpredictable currents, especially where there are narrow openings/parts of harbor Tsunami bores and amplified waves resulting in swamping of boats and damage to docks Eddies/whirlpools causing boats to lose control Drag on large keeled boats causing damaging forces to boats tied to docks Collision with other boats, docks, and debris in the water Dangerous tsunami conditions can last tens of hours after first wave arrival, causing problems for inexperienced and unprepared boaters who take their boats offshore The National Weather Service, National Tsunami Warning Center in Alaska provides tsunami information for California. The following are significant tsunami Alert levels: WATCH - Issued to alert emergency managers and the public of an event which may later impact the Watch area. May be upgraded to an Advisory or Warning - or canceled - based on updated information and analysis. ADVISORIES Peak tsunami wave heights between 1-3 feet are expected, indicating strong and dangerous currents can be produced in harbors but inundation of dry land is unlikely. WARNINGS Tsunami wave heights could exceed 3 feet, indicating very strong, dangerous currents and inundation of dry land is anticipated.

5 General Tsunami Information for Maritime Communities Page 5 Actionable Tsunami Alert Levels: Tsunami Advisories and Warnings are the two actionable Alert levels for maritime communities. Actions taken will depend on the Alert level and the forecasted tsunami wave height or amplitude for a particular harbor. For both Advisory and Warning level events, it is important that clear and consistent directions are provided to the entire boating community and waterfront businesses. If there is not sufficient time to use the playbooks, consider the following general actions for your maritime communities for either Advisory or Warning level events: ADVISORY All activities below should be completed no later than one hour before forecasted tsunami arrival. Evacuate the public from all structures and vessels in the water. Coordinate with local law enforcement to limit access of public along waterfront areas. All personnel working on or near the water should wear personal flotation devices. Advise facility maintenance to shut off fuel to fuel docks, and all electrical and water services to all docks. Secure and strengthen all mooring lines throughout harbor, specifically areas near the entrance or narrow constrictions. Do not allow public to re-enter structures and vessels in the water until Advisory is canceled. WARNING All activities below should be completed no later than one hour before forecasted tsunami arrival. Evacuate the public and harbor personnel from all structures and vessels in the water, as well as all land-ward areas identified in the mapped tsunami evacuation area (last page). Advise facility maintenance to shut off fuel to fuel docks, and all electrical and water services to all docks. Secure and strengthen all mooring lines throughout harbor, specifically areas near the entrance or narrow constrictions. Do not allow public to re-enter tsunami evacuation area until Warning is downgraded or cancelled. Follow instructions for an Advisory if Warning is downgraded to an Advisory level.

6 2011 M8.8 Chile Event Background Information: Alert level = Advisory Peak Amplitude = 0.9 meters (observed) Peak Velocity = 4 knots Projected duration of strong currents (see location map below): 3 knots = 20 hrs; 6 knots = 0 hrs; 9 knots = 0 hrs Specific Instructions: Follow general guidance for Advisory-level tsunamis (pg 2) Strong currents and potential scour are expected in areas identified in blue on the map to the right. Consider relocating vessels located within 100 meters (300 feet) of these areas. Specific areas where vessels should be relocated from and docks secured: Under bridges and U dock (completed with maritime community input) Current-Threshold Map D Page 6 D = areas of observed damage from recent events Safe areas for repositioning vessels within Santa Cruz Harbor:..(completed with maritime community input) Map of areas of potential sedimentation, debris accumulation, and extreme shallow conditions (keel damage)

7 M9 Cascadia Scenario Current-Threshold Map Page 7 Background Information: Alert level = Advisory Peak Amplitude = 1.2 meters Peak Velocity = 7 knots Projected duration of strong currents (see location map below): 3 knots = 40 hrs; 6 knots = 10 hrs; 9 knots = 0 hrs Specific Instructions: Follow general guidance for Advisory-level tsunamis (pg 2) Strong currents and potential scour are expected in areas identified in blue and yellow on the map to the right. Consider relocating vessels located within 100 meters (300 feet) of these areas. Specific areas where vessels should be relocated and docks secured: Docks under bridge and U and V docks.. (completed with maritime community input) Safe areas for repositioning vessels within Santa Cruz Harbor:.. (completed with maritime community input) Map of areas of potential sedimentation, debris accumulation, and extreme shallow conditions (keel damage)

8 2011 M9 Japan Event Current-Threshold Map Page 8 Background Information: Alert level = Warning Peak Amplitude = 1.8 meters (observed) Peak Velocity = knots Projected duration of strong currents (see location map below): 3 knots = 40 hrs; 6 knots = 10 hrs; 9 knots = <5hrs Specific Instructions: Follow general guidance for Warning-level tsunamis (pg 2) Strong currents and potential scour are expected in areas identified in blue and yellow on the map to the right. Consider relocating vessels located within 100 meters (300 feet) of these areas. Specific areas where vessels should be relocated and docks secured:. (completed with maritime community input) D D D D D = areas of observed damage from recent events Safe areas for repositioning vessels within Santa Cruz Harbor:.. (completed with maritime community input) Map of areas of potential sedimentation, debris accumulation, and extreme shallow conditions (keel damage)

M9.2 Eastern Aleutian/Alaska Scenario Current-Threshold Map Page 9 Background Information: Alert level = Warning Peak Amplitude = 6 meters Peak Velocity = +15 knots Projected duration of strong

scour are expected in areas identified in blue yellow-red on the map to the right. Consider relocating vessels located within 100 meters (300 feet) of these areas.

9 M9.2 Eastern Aleutian/Alaska Scenario Current-Threshold Map Page 9 Background Information: Alert level = Warning Peak Amplitude = 6 meters Peak Velocity = +15 knots Projected duration of strong currents (see location maps below): 3 knots = 40 hrs; 6 knots = 20 hrs; 9 knots = 10 hrs Specific Instructions: Follow general guidance for Warning-level tsunamis (pg 2) Strong currents and potential scour are expected in areas identified in blue yellow-red on the map to the right. Consider relocating vessels located within 100 meters (300 feet) of these areas. Specific areas where vessels should be relocated from and docks secured: NONE (completed with maritime community input) Safe areas for repositioning vessels within San Cruz Harbor: NONE (completed with maritime community input) Map of areas of potential sedimentation, debris accumulation, and extreme shallow conditions (keel damage)

Page 10 Santa Cruz Harbor Maritime Community Reference Material: Notable Historical Tsunamis and State Tsunami Program Modeling Results Notable Historical Tsunamis: The following table provides very

Note that the largest, most damaging tsunamis in Santa Cruz County history have come from large earthquakes in the Alaska-Aleutian Islands region.

10 Page 10 Santa Cruz Harbor Maritime Community Reference Material: Notable Historical Tsunamis and State Tsunami Program Modeling Results Notable Historical Tsunamis: The following table provides very basic information about historical tsunami events; not all tsunamis are represented, especially minor or small tsunamis. Note that the largest, most damaging tsunamis in Santa Cruz County history have come from large earthquakes in the Alaska-Aleutian Islands region. Although the potential for local tsunamis exists, they are much less frequent than distant source tsunamis. Modeled Tsunami Scenarios: Because very large tsunamis are infrequent and the likelihood that the largest potential tsunamis have not yet occurred in Santa Cruz County, the state tsunami program developed a suite of maximum credible tsunami scenarios as part of their tsunami inundation mapping project for local evacuation planning. The general tsunami wave height for key locations from these scenarios are provided below. As identified in the historical tsunami table, the largest tsunamis could occur from large earthquakes in the Alaska-Aleutian Islands region, or from a large submarine landslide offshore in Monterey Bay. Additional information about the length of activity for recent events: Tsunamis activity can last for many hours after first wave arrival. The table to the right shows nearby tide gauge information (Monterey) for several recent, real events on the timing of the various tsunami peaks, i.e. how many hours after arrival did the maximum positive wave occur, the maximum negative wave and the maximum peak to trough wave. This information shows that peak/maximum tsunami conditions can occur nearly 14 hours after first arrival. Monterey Tide Gauge Information 2009 Samoa Arr. Time Max. Amp. Assoc. Trough Height Hrs after arrival Max Peak to Trough Hrs After arrival Max SL Hrs After Arrival 2010 Chile Japan

11 NOTE: The safety of the boating public should outweigh the benefit of saving boats and harbor property during a tsunami. For most harbors in California, it is safer to keep boats docked during a tsunami because most tsunamis are relatively small. On the rare occasion when a large, damaging tsunami and associated strong currents are expected and there are no safe areas within the harbor, the boat owner may consider taking their boat offshore. There are a number of factors that should be considered prior to recommending boats evacuate offshore prior to the arrival of the tsunamis, including: (1) the SIZE of the tsunami; (2) is there sufficient TIME to get to the 30 fathom depth, which has been evaluated as safe depth for boats during distant source tsunamis (map at right); (3) the PREPAREDNESS of the boat and its captain to stay at sea over 24 hours; (4) the WEATHER at sea could be as dangerous as the tsunami itself; and, (5) if significant damage occurs within the harbor, boaters should have enough fuel and supplies to travel to a non-damaged harbor. Plan for Safe Offshore Evacuation of Boats harbor 30 fathoms 50 fathoms Page 11 Note for trailer boat owners: Expect congested boat ramps and remember that you have to get your boat to the trailer, out of the water, and out of the tsunami zone before the tsunami arrives. Information on this page could be replaced with harbor specific evacuation plan/map.

State Tsunami Inundation Zone Map for the Santa Cruz Area Page 12 This tsunami inundation map was prepared to assist cities and counties in identifying their tsunami hazard.

12 State Tsunami Inundation Zone Map for the Santa Cruz Area Page 12 This tsunami inundation map was prepared to assist cities and counties in identifying their tsunami hazard. It is intended for local jurisdictional, coastal evacuation planning uses. The red inundation line represents the maximum considered tsunami inundation from a number of extreme, yet realistic, tsunami sources. In other words, people within the red-colored zones could get wet; people uphill or inland from these areas should be safe during any tsunami. This map, or the local tsunami evacuation map/plan, should be used for evacuation from a Warning-level tsunami event unless otherwise directed by local emergency management officials. For digital copies of this map or inundation maps for other portions of California, visit Information on this page could be replaced with community specific evacuation plan/maps.

What is a tsunami? Capital Regional District Tsunami Frequently Asked Questions (FAQ s) Tsunami (soo-nah-mee)

What is a tsunami? Capital Regional District Tsunami Frequently Asked Questions (FAQ s) Tsunami (soo-nah-mee) Tsunami (soo-nah-mee) Tsunamis (Japanese translation harbour wave ) are waves with a great distance between crests, and are caused by any widespread, sudden movement of large volumes of water. The tsunami