{"id":28,"date":"2018-06-25T12:50:35","date_gmt":"2018-06-25T16:50:35","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/chapter\/case-study-2-1964-port-alberni-tsunami\/"},"modified":"2018-06-25T15:21:15","modified_gmt":"2018-06-25T19:21:15","slug":"case-study-2-1964-port-alberni-tsunami","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/chapter\/case-study-2-1964-port-alberni-tsunami\/","title":{"raw":"5.1 - Case Study: 1964 Port Alberni Tsunami","rendered":"5.1 – Case Study: 1964 Port Alberni Tsunami"},"content":{"raw":"On the afternoon of Good Friday, March 27, 1964, the strongest earthquake recorded in North America, and the second strongest ever recorded, occurred in Alaska. The Great Alaskan Earthquake was a 9.2 magnitude subduction zone (megathrust) earthquake located at a depth of approximately 25 kilometres. It lasted four minutes and 38\u00a0 seconds. 131 people died in the earthquake and ensuing tsunami's (USGS, 2012).\r\n\r\nThe epicentre of the earthquake was 125 kilometres\u00a0east of Anchorage, Alaska, where many inadequately engineered houses, buildings and infrastructure were\u00a0damaged or destroyed.\u00a0Three hundred kilometers southwest, some areas near Kodiak were permanently raised by 9.1 metres. Southeast of Anchorage, areas around the head of Turnagain Arm near Girdwood and Portage dropped as much as 2.4 metres. A massive underwater slide at Port Valdez in Prince William Sound created an 8.2 metre tsunami that destroyed the village of Chenega, killing 23 of the 68 people who lived there. Post-quake tsunamis severely affected Whittier, Seward, Kodiak and other Alaskan communities, as well as people and property in Oregon, California and British Columbia.\r\n\r\n[caption id=\"attachment_192\" align=\"aligncenter\" width=\"400\"]\"Figure<\/a> Figure 8.11 Calculated travel time map for the tectonic tsunami produced by the 1964 earthquake in Alaska. Map does not show the height or strength of the waves, only the calculated travel times. Number represents time in hours for the wave to reach the destination.[\/caption]\r\n\r\nTwo types of tsunami were produced as a result of the earthquake: a\u00a0tectonic tsunami<\/strong>\u00a0caused by the movement of the tectonic plates, and\u00a0subaerial landslide (or submarine) tsunami<\/strong>\u00a0caused by underwater landslides. About 20 of these smaller tsunamis were responsible for the majority of the tsunami damage in over 20 countries, including Canada, Peru, New Zealand, Papua New Guinea and Japan.\u00a0The largest recorded wave was at\u00a0Shoup Bay, Alaska, at\u00a0 height of about 67 metres.\r\n\r\nThree hours after the quake, a 1.4 metre tsunami wave reached Prince Rupert, BC, and did little damage. Then, around midnight, the first of two waves began travelling up the 40 kilometre\u00a0Alberni Inlet toward the towns of Alberni and Port Alberni. The narrow inlet amplified the size and intensity of the wave, and when it struck the two towns it had a height of 2.44 metres. One hour later, a second, larger wave of 3.05 metres hit. It was the second wave that caused most of the damage, lifting\u00a0houses off their foundations and sweeping\u00a0log booms on shore. The second wave was followed by four more waves ranging in height from\u00a01.52 metres and 1.83 metres\u00a0and ocurring at roughly 90 minute intervals.\r\n\r\nIn total, the tsunami washed away away 55 homes and damaged 375 others. It\u00a0caused $5 million in damage in Port Alberni and Alberni. The mill at Port Alberni, which employed 4,000 people, was temporarily closed. Incredibly, there were no fatalities in either town. The tsunami lead directly to the amalgamation of Alberni and Port Alberni into a single town in 1966.\r\n

Animation of Tsunami Generated by the Earthquake<\/h2>\r\nIf you are reading this in print, you can see the animation at https:\/\/www.youtube.com\/watch?v=rJOGJApz1M0<\/a>.\r\n

Attributions<\/span><\/h2>\r\nFigure 8.11<\/strong> Calculated Travel Time Map for 1964 Alaska Tsunami (http:\/\/en.wikipedia.org\/wiki\/File:Calculated_Travel_Time_Map_for_1964_Alaska_Tsunami.jpg<\/a>) by Ngdchazards\u00a0 used under CC BY SA 3.0 (http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en<\/a>)","rendered":"

On the afternoon of Good Friday, March 27, 1964, the strongest earthquake recorded in North America, and the second strongest ever recorded, occurred in Alaska. The Great Alaskan Earthquake was a 9.2 magnitude subduction zone (megathrust) earthquake located at a depth of approximately 25 kilometres. It lasted four minutes and 38\u00a0 seconds. 131 people died in the earthquake and ensuing tsunami’s (USGS, 2012).<\/p>\n

The epicentre of the earthquake was 125 kilometres\u00a0east of Anchorage, Alaska, where many inadequately engineered houses, buildings and infrastructure were\u00a0damaged or destroyed.\u00a0Three hundred kilometers southwest, some areas near Kodiak were permanently raised by 9.1 metres. Southeast of Anchorage, areas around the head of Turnagain Arm near Girdwood and Portage dropped as much as 2.4 metres. A massive underwater slide at Port Valdez in Prince William Sound created an 8.2 metre tsunami that destroyed the village of Chenega, killing 23 of the 68 people who lived there. Post-quake tsunamis severely affected Whittier, Seward, Kodiak and other Alaskan communities, as well as people and property in Oregon, California and British Columbia.<\/p>\n

\"Figure<\/a>
Figure 8.11 Calculated travel time map for the tectonic tsunami produced by the 1964 earthquake in Alaska. Map does not show the height or strength of the waves, only the calculated travel times. Number represents time in hours for the wave to reach the destination.<\/figcaption><\/figure>\n

Two types of tsunami were produced as a result of the earthquake: a\u00a0tectonic tsunami<\/strong>\u00a0caused by the movement of the tectonic plates, and\u00a0subaerial landslide (or submarine) tsunami<\/strong>\u00a0caused by underwater landslides. About 20 of these smaller tsunamis were responsible for the majority of the tsunami damage in over 20 countries, including Canada, Peru, New Zealand, Papua New Guinea and Japan.\u00a0The largest recorded wave was at\u00a0Shoup Bay, Alaska, at\u00a0 height of about 67 metres.<\/p>\n

Three hours after the quake, a 1.4 metre tsunami wave reached Prince Rupert, BC, and did little damage. Then, around midnight, the first of two waves began travelling up the 40 kilometre\u00a0Alberni Inlet toward the towns of Alberni and Port Alberni. The narrow inlet amplified the size and intensity of the wave, and when it struck the two towns it had a height of 2.44 metres. One hour later, a second, larger wave of 3.05 metres hit. It was the second wave that caused most of the damage, lifting\u00a0houses off their foundations and sweeping\u00a0log booms on shore. The second wave was followed by four more waves ranging in height from\u00a01.52 metres and 1.83 metres\u00a0and ocurring at roughly 90 minute intervals.<\/p>\n

In total, the tsunami washed away away 55 homes and damaged 375 others. It\u00a0caused $5 million in damage in Port Alberni and Alberni. The mill at Port Alberni, which employed 4,000 people, was temporarily closed. Incredibly, there were no fatalities in either town. The tsunami lead directly to the amalgamation of Alberni and Port Alberni into a single town in 1966.<\/p>\n

Animation of Tsunami Generated by the Earthquake<\/h2>\n

If you are reading this in print, you can see the animation at https:\/\/www.youtube.com\/watch?v=rJOGJApz1M0<\/a>.<\/p>\n

Attributions<\/span><\/h2>\n

Figure 8.11<\/strong> Calculated Travel Time Map for 1964 Alaska Tsunami (http:\/\/en.wikipedia.org\/wiki\/File:Calculated_Travel_Time_Map_for_1964_Alaska_Tsunami.jpg<\/a>) by Ngdchazards\u00a0 used under CC BY SA 3.0 (http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/deed.en<\/a>)<\/p>\n","protected":false},"author":484,"menu_order":11,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-28","chapter","type-chapter","status-publish","hentry"],"part":3,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/pressbooks\/v2\/chapters\/28","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/wp\/v2\/users\/484"}],"version-history":[{"count":2,"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/pressbooks\/v2\/chapters\/28\/revisions"}],"predecessor-version":[{"id":214,"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/pressbooks\/v2\/chapters\/28\/revisions\/214"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/pressbooks\/v2\/parts\/3"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/pressbooks\/v2\/chapters\/28\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/wp\/v2\/media?parent=28"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/pressbooks\/v2\/chapter-type?post=28"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/wp\/v2\/contributor?post=28"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/readingsnh\/wp-json\/wp\/v2\/license?post=28"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}