Understanding Natural Hazards: Hilo’s Tsunami History & Communication Preparedness Issues and Response Improvements

Introduction Tsunamis are a series of waves of very long length and period that can travel up to one thousand kilometers per hour in the open ocean. They are caused by disturbances that displace large volumes of water and are usually generated by seafloor displacement during earthquakes, but they can also be caused by volcanic eruptions, submarine landslides, and oceanic bolide impacts. Tsunamis can impact coasts on either ocean-wide, regional, or local scales. In the open ocean the tsunami wave height may be only a meter or two, but as the wave approaches shallow water it slows down and begins shoaling resulting in dramatic increases in wave height. Damage from a tsunami is caused by inundation, wave impact, and sediment erosion and deposition. In general, the larger the tsunami, the greater the impact (SOEST, 2012). Tsunamis have killed more people in the Hawaiian Islands than all other natural disasters combined. The Hawaiian Islands have been hit by numerous tsunamis, some generated thousands of miles away, others the result of earthquakes and landslides occurring within the archipelago (Hawaiian Encyclopedia, 2012). Big Island, Hilo: Brief Tsunami History (When, Origin, Magnitude, and Impact) Tsunamis are an ever-present threat to the people of Hawaii and have proven to be one of the most deadly natural disasters on the islands (Sutton, 2011). An estimated 221 people have been killed by tsunamis in Hawaii in the twentieth century. Most of these deaths occurred on the Big Island during the tsunamis of 1946 and 1960, two of the largest tsunamis to strike in the Pacific (Pacific Disaster Center, 2012). Seven of the fifteen destructive tsunamis that reached the Big Island between 1812 and 1975 led to damage in Hilo; six of those seven were caused by earthquakes off the Chilean coast (Sutton, 2011). Historically, the city of Hilo has been the target of many destructive tsunamis (Sutton, 2011). Approximately 25 percent of the property and population of Hilo are located within its tsunami inundation area (Sutton, 2011). The natural shape of Hilo Bay amplified the waves, which then surged onto land. Hilo has a population of approximately 45,000 and is the second largest city in the Hawaiian Islands (Hawaii Encyclopedia, 2012). Following a brief history of tsunamis on the Big Island -- focused on Hilo: 1868: An earthquake measuring 8.0 on the Richter scale on the island of Hawai‘i causes a landslide that destroys a village and creates a localized tsunami reported to be more than 60 feet high. Nearly every European-style home in the Ka‘ū district of Hawai‘i Island was destroyed. The mud flow buries a village of 31 people along with about 50 animals, killing 40 people in all. The tsunami kills 48 people when water surges ashore up to 60 feet high, sweeping away the ancient village of ‘Āpua in Puna (Hawaii Encyclopedia, 2012). 1877: A large earthquake occurs near Peru, and a tsunami arrives in Hilo before dawn. 37 houses are destroyed, 45 people are killed, and many more injured (Hawaii Encyclopedia, 2012). 1918: A 5-foot high tsunami arrives in Hilo, doing little damage (Hawaii Encyclopedia, 2012). 1923: An earthquake in the Aleutian Islands generates a tsunami that sends waves to more than 20 feet above normal in the Waiākea area of Hilo (Hawaii Encyclopedia, 2012). 1946: The tsunami of April 1, 1946 was the deadliest natural disaster in the history of modern Hawaiʻi (Nishimoto, 2002). This tsunami was generated by a magnitude 7.1 earthquake in the Aleutian Islands (Pacific Disaster Center, 2012). An estimated 159 people in the Hawaiian Islands were killed, including 96 in Hilo and 24 in Laupāhoehoe on Hawai‘i Island. The tsunami brought 15 waves in all, rising up to 56 feet above sea level in some places, and 33 feet in Hilo where close to 500 homes and businesses are destroyed and more than 1,000 more damaged, causing an estimated $26 million in damage, including railroads, bridges, piers and ships (Hawaii Encyclopedia, 2012). 1952: On November 4, 1952 a tsunami was generated by a magnitude 8.2 earthquake on the Kamchatka Peninsula in the USSR. In Hawaii, property damage from these 12-foot waves was estimated at $800,000-$1,000,000; no lives were lost. The waves beached boats, caused houses to collide, destroyed piers, scoured beaches, and moved road pavement especially in Hilo (Pacific Disaster Center). 1960: This tsunami was caused by an earthquake in Chile. The Chilean earthquake -- magnitude 8.3 -- occurred 6,600 miles away from the Hawaiian Islands. The tsunami waves generated by the earthquake took more than 15 hours to reach Hawai‘i’s shores. Hilo once again took the brunt of the damage as it was hit by at least seven significant tsunami waves over a 2-hour period. The third wave was the most destructive. In Hilo Bay, the tsunami created a bore that rushed ashore at a speed reported to be more than 37 miles per hour, surging water as high as 36 feet above sea level. In all, 61 people were killed in Hilo, with 43 more requiring medical care for their injuries. In addition, at least 229 homes were destroyed, as well as 308 public structures and businesses. The destruction was most severe near Hilo’s Kamehameha Ave., where entire city blocks were washed away. Damage was estimated up to $50 million. Many people died because they went to the shoreline to investigate what was happening as the water drained out from the bay and river (Hawaii Encyclopedia, 2012). 1964: One of North America’s largest earthquakes ever recorded -- magnitude 8.4 on the Richter scale -- occurs in Alaska, sending tsunami waves toward the Hawaiian Islands. In Hilo, the waves rise to more than 12.5 feet. No people die in the Hawaiian Islands (Hawaii Encyclopedia, 2012). 1975: November 29, two strong earthquakes shake the southeast region of Hawai‘i Island, causing a small eruption of Kīlauea Volcano and generating a localized tsunami that hits the remote Ka‘ū area on the southeast shore of the island of Hawai‘i. One of the 1975 earthquakes registered at least 7.2 on the Richter scale. The tsunami comes ashore near the site of an old Hawaiian village that is now a campground area called Halapē. The ground in the area sinks some 12 feet and rocks fall from the cliffs above. A tsunami wave sweeps campers onto a rugged lava field and washes some of them into a huge crack in the lava, killing two people and injuring many more. One of the tsunami waves traveled more than 300 feet inland (Hawaii Encyclopedia, 2012). 2010: At approximately 8:34pm on February 26, 2010, a magnitude 8.8 earthquake occurred in the subduction zone off the south-central coast of Chile. Its epicenter was relatively close to the location of the Chilean earthquake that generated the devastating 1960 tsunami. The tsunami waves arrived in Hilo at 11:38 am, with wave heights of less than 3.1 feet (Sutton, 2011). 2011: the Big Island of Hawaii did sustain some damage as a result of the tsunami of March 11, 2011; however, the damage reported was relatively minimal. There were no deaths or serious injuries reported (Fischer, 2011). The King Kamehameha Kona Beach Hotel got a foot of water in the lobby and canoes in the harbor were destroyed. Flooding was also reported in Kahului. The waters surged in some harbors hours after the initial wave hit. At Napoopoo at Kealakekua Bay, one wave reached at least 100 feet inland and an elevation of 11 or 12 feet (Star-Advertiser, 2011). Communication Preparedness Issues A review of historical data for Hawaii reveals that significant tsunamis have been reported for only four of twenty-six potentially tsunamigenic earthquakes from 1868 through 2009 with magnitudes of 6.0 or greater. During the same time period, three significant tsunamis have been reported for substantially smaller earthquakes. This historical perspective, the fact that the last significant local tsunami occurred in 1975, and an understandable preoccupation with tsunamis generated around the margins of the Pacific suggest apparent deficiencies in i) personal awareness of what to do in the event of a possible local tsunami, ii) the distribution of instrumentation capable of providing rapid confirmation that a local tsunami has been generated, and iii) the subsequent issuance of timely warnings for local tsunamis (Walker, 2010). Many of the fatalities and injuries associated with past tsunamis can be attributed to such deficiencies as lack of awareness of tsunami hazards, human error, inadequate support of mitigation efforts, and poor communications between scientists, government agencies, and the general public (Walker, 1996). 1946 and 1960 tsunamis caused tragic loss of life and enormous economic damage in Hilo and along the shores of the Hawaiian Island chain. Even though the government agencies knew there was a tsunami alert and the media were broadcasting warnings, the 1960 tsunami took the lives of sixty-one people in Hilo only fourteen years after ninety-six people were killed during the 1946 event. Over twelve hours notice of a possible large tsunami was given in 1960 and the siren warning system sounded more than four hours prior to the event. Contributing to the tragic loss of life was a lack of communication between government agencies in addition to media inaccuracies and a public that was not educated in tsunami safety (Johnston, 2012). The most serious deficiencies are found in the following areas: a lack of knowledge of tsunami hazards at nearly every level of our society, an ineffective warning system for locally generated tsunamis primarily affecting the Kona, Ka,u, and Puna coasts of the Big Island, and the probability of unacceptably high levels of false warnings for Pacific-wide tsunamis (Walker, 1996). Most aspects of communications are continually tested and upgraded by State and County Civil Defense agencies, as well as the Pacific Tsunami Warning Center. However, one perceived glaring deficiency in communications is likely unless corrective actions are taken. Because of an absence of instrumentation along parts of the Puna and Kona coastline from Punaluu to Kapoho, a small unfelt earthquake could generate a highly localized but destructive tsunami along shorelines popular with residents and tourists -- i.e., Punaluu, Pohoiki, and Ahalanui --, and in coastal campground areas of the Hawaii Volcanoes National Park. No warnings would be possible in those areas for such a tsunami although some other shorelines at risk on the Big Island are instrumented with devices -- i.e., along the Kona Coast from Honokohau to Milolii -- that would detect such tsunamis and provide Civil Defense personnel with an opportunity to sound warning sirens. History confirms that a highly localized destructive tsunami will occur (Walker, 2004). Even though data from the National Oceanic and Atmospheric Administration’s tsunami buoys has a substantial history of success, warnings perceived as “false” by the public are always a possibility. The people of Hawaii need to understand the limitations of warning systems. They need to know that once the reliability of data used in the warning system is established, false warnings will be reduced or eliminated. Also, for some warnings only limited evacuations may be required (Walker, 2004). Not only does Hawaii have a warning system for Pacific-wide tsunamis but also a warning system for locally generated tsunamis for part of the Big Island. This system also provides an early warning for the rest of the State should a large tsunami occur on the Kona Coast. Historical data and the successful operation of the tsunami sensors on the Kona Coast suggest that local warning criteria should be reviewed to eliminate overcautious, and obviously false, local warnings. Also, some criteria might be eliminated so that warnings can be called more quickly. Necessary upgrades and expansions of the local warning system should be made. These upgrades should be done by informing the public on the differences and characteristics of both Pacific-wide and local warnings (Walker, 2004). Because of existing potential deficiencies in education, instrumentation, and warnings, locally generated tsunamis may be far greater risk to loss of life in the Hawaiian Islands than Pacific-wide tsunamis. These deficiencies should be addressed and corrected by public officials, educators, residents, and visitor industry personnel prior to, rather than after, the next locally generated tsunami (Walker, 2010). Communication Response Improvements Effective tsunami mitigation can only be accomplished through continual awareness education for the public, media and emergency personnel, and with accurate and timely warnings (Johnston, 2012). Messages that are clear, concise, and instructive increase public understanding and allow people to take practical steps to protect themselves before, during, and after a crisis (Sutton, 2011). As the Big Island does not have network television broadcast news stations, local residents rely on more than a dozen AM and FM radio stations, two major daily newspapers, and several smaller weekly papers. These are complemented by online news sites like Hawaii 24/7. Hilo is also the seat for the Hawaii County Civil Defense, which is responsible for coordinating preparedness and response activities for the Big Island (Sutton, 2011). In the weeks prior to 2010 tsunami, Hilo conducted a tsunami drill, exercising the coordination among county departments, testing alert mechanisms, disseminating information via local media, and identifying areas for improvement. These yearly drills, along with monthly tests of the sirens and alert systems, help ensure the local government and its many partners are prepared for an actual event. Alerts on the Big Island include sirens, emergency alert systems (EAS) messages on broadcast radio and television, and public service announcements. Additional strategies include door-to-door to homes in the evacuation zone, helicopter flyovers of “off-the-grid” areas, and police patrols with bullhorns announcing mandatory evacuations. Hawaii County has also implemented a number of self-subscription services that provide alert information to desktop computers and mobile phones, raising the attention of those who have registered for key information (Sutton, 2011). Public officials also monitor social networking responses and post accurate information in reply (Sutton, 2011). In terms of educating the population and reminding them about tsunami risks, Hilo is home to Hawaii’s only tsunami museum, mostly dedicated to the understanding of the 1946 Pacific Tsunami (Wikipedia, 2012). Tsunami Awareness Month is held in April to commemorate the lives lost to the 1946 disaster. In April, NOAA scientists and Civil Defense volunteers visit the schools across the State located in hazardous zones to help them understand risks and improve evacuation plans. The same is done by scientists from the Pacific Tsunami Warning Center and the International Tsunami Information Center to help families prepare for tsunamis (Hawaii 24/7, 2010). Regarding mitigation planning, local public and private authorities should i) implement modeling to determine the effect on Hawaii of a “100-year 9.0 magnitude earthquake” from regions in the Western and Southwestern Pacific, including Japan, ii) expand and upgrade the local warning system, iii) implement standardized tsunami education in schools, iv) review warning criteria for local earthquakes, v) harden facilities against salt water flooding, and vi) understand the potential social and economic impact of tsunamis so as to minimize losses and speed recovery in the next large tsunami (Walker, 2004). Historic memory about preparedness efforts on the Big Island is dominated by past tsunami experience and the recognition of the need for increased public education and communication among networked organizations (Sutton, 2011). The 1994 East Java tsunami event was the impetus for a strong local preparedness campaign in Hilo, resulting in increased knowledge about tsunami planning, including recognizing the physical signs of a tsunami, implementing alert systems and street signage, and integrating organizations at the local level (Sutton, 2011). Local preparedness measures increased communication among organizations through coordination with Community Emergency Response Team, opened the doors of the Emergency Operations Center (EOC) to local news reporters, making them communication partners and extensions of the public information function within Civil Defense (Sutton, 2011). County officials have described local broadcast media as extremely important partners for disseminating hazard information to the public in times of emergency (Sutton, 2011). Media outlets have been outfitted with generators and promised fuel access if critical infrastructure is disabled and radio becomes the sole source of public information. News media receive press credentials and passes that allow them access to the EOC. Throughout response, media personnel are able to monitor EOC operations and do not need to wait for official briefings or news releases before disseminating information (Sutton, 2011). The State communication warning process for tsunamis involves several agencies. Seismic recording stations at the U.S. Geological Survey’s (USGS) Hawaiian Volcanic Observatory (HVO) on the Big Island capture the earthquake from its many recording stations. HVO geologists usually have a position of the earthquake within five minutes of the event and send this information to local civil defense authorities. The information from HVO is also immediately provided to the National Oceanographic and Atmospheric Administration’s (NOAA) Pacific Tsunami Warning Center (PTWC) on Oahu and to local civil defense. PTWC makes its own assessment whether to issue or not a bulletin minutes after the HVO report, with its own estimation of location and a different and more precise estimate of the quake’s magnitude. The PTWC is responsible for communicating the information to other public authorities. The PTWC continuously monitors data across the state, mostly from the Big Island since that is where the majority of seismic activity occurs. Primary responsibility for informing the public about emergency situations lies with Civil Defense (CD) which controls the Emergency Alert System (EAS). Multiple communication systems exist between the PTWC and CD; phone lines are backed up with satellite and radio systems. PTWC has a dedicated phone line supported by the Federal Emergency Management Agency. They also communicate via text bulletins through normal weather channels, such as the World Meteorological Organization, an agency of the United Nations, and Advanced Weather Interactive Processing System, a National Weather Service program (Francica, 2006). In 2007, the governor of Hawaii created a committee to suggest methods to include multiple non-traditional communications means to disseminate information (Lingle, 2007). The key recommendations for improving the emergency communications plan were i) update the State of Hawai`i Emergency Alert System plan, ii) establish a “media center” in the CD emergency operations, iii) install dedicated phone lines for accredited electronic and print news organizations, iv) provide updates every thirty minutes to improve the flow of information to the public and help refute unsubstantiated rumors and other sources of false information, v) assign as a liaison officer to be dedicated to the media at any activation of the State EOC, vi) establish a dedicated CD Web site to provide the media with updates online to assist media organizations, vii) assess the feasibility and technological capability of using the text messaging function for emergencies, viii) explore the possibility of communicating via electronic message signs on the freeways, ix) increase public awareness about emergency preparedness, x) work with the Hawai`i consular corps, xi) identify sign language translators, xii) news outlets to restore power during an outage, xiii) provide diesel fuel for backup power generators during extended blackout periods, and xiv) track the progress of recommendations (Lingle, 2007). 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Wikipedia. “Hilo, Hawaii”, accessed on March 3, 2012. http://en.wikipedia.org/wiki/Hilo,_Hawaii Wikipedia. “List of historic tsunamis”, accessed on March 5, 2012. http://en.wikipedia.org/wiki/List_of_historic_tsunamis