Lessons from the 1960 Chile Earthquake Tsunami for New Zealand Coastal Communities
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Kotuitui: New Zealand Journal of Social Sciences Online ISSN: (Print) 1177-083X (Online) Journal homepage: https://www.tandfonline.com/loi/tnzk20 Developing an effective tsunami warning system: Lessons from the 1960 Chile earthquake tsunami for New Zealand coastal communities David Johnston , Rylee Pettersson , Gaye Downes , Douglas Paton , Graham Leonard , Katharine Pishief & Rob Bell To cite this article: David Johnston , Rylee Pettersson , Gaye Downes , Douglas Paton , Graham Leonard , Katharine Pishief & Rob Bell (2008) Developing an effective tsunami warning system: Lessons from the 1960 Chile earthquake tsunami for New Zealand coastal communities, Kotuitui: New Zealand Journal of Social Sciences Online, 3:2, 105-120, DOI: 10.1080/1177083X.2008.9522436 To link to this article: https://doi.org/10.1080/1177083X.2008.9522436 Copyright Taylor and Francis Group, LLC Published online: 19 Apr 2010. Submit your article to this journal Article views: 647 View related articles Citing articles: 2 View citing articles Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tnzk20 Johnston et al.—Developing an effective tsunami warning system 105 Kōtuitui: New Zealand Journal of Social Sciences Online, 200 8, Vol. 3: 105–120 1177–083X/08/0302–0105 © The Royal Society of New Zealand 2008 Developing an effective tsunami warning system: lessons from the 1960 Chile earthquake tsunami for New Zealand coastal communities DAVID JOHNSTON 1 RYLEE PETTERSSON 2 GAYE DOWNES 1 DOUGLAS PATON 3 GRAHAM LEONARD 1 KATHARINE PISHIEF 1 ROB BELL 4 1Joint Centre for Disaster Research GNS Science/ School of Psychology Massey University Wellington PO Box 756 Wellington 6140, New Zealand 2Ministry of Civil Defence and Emergency Management Wellington, New Zealand (currently private researcher, Nelson) 3School of Psychology University of Tasmania Launceston, Tasmania, Australia 4National Institute of Water & Atmospheric Research PO Box 11115 Hamilton 3251, New Zealand Abstract The magnitude 9.5 earthquake on 22 May 1960 in southern Chile was the largest instrumentally recorded earthquake in the 20th century. It generated a tsunami that swept the shores of Chile and radiated out across the Pacific, with the major loss of life in Chile and, despite warnings being issued, in both Hawai‘i and Japan. The absence of a Pacific-wide tsunami warning system at the time meant that the tsunami struck New Zealand without an official warning being issued. Fortunately, there was no loss of life despite widespread damage to coastal facilities. A large aftershock occurred in Chile 3 days later (25 May) and fears about a tsunami from this event resulted in the broadcasting of a nationwide warning on radio in New Zealand. Newspapers of the day reported that thousands of people around the country were evacuated, making this the largest and most widespread evacuation in New Zealand’s history. Almost the entire population of Whitianga, Waihi Beach, Whakatane, Ohope, and Opotiki were moved to high ground for several hours and, in many other communities, people self-evacuated from coastal fringes. After the event, there was much discussion in the newspapers of the K07025; Online publication date 8 December 2008 Received 5 December 2007; accepted 28 October 2008 106 Kōtuitui, 2008, Vol. 3 need to improve both warnings and public awareness of the hazard, and of the appropriate response to warnings. Over the 40 years from 1960 up to the 26 December 2004 Indian Ocean tsunami, public awareness of New Zealand’s tsunami risk and preparedness had waned. Since 2004, the renewed focus on tsunami has built on a range of improvements in emergency management policies and practices, and the lessons identified from the event paved the way for a number of new initiatives to get underway to enhance the New Zealand’s tsunami warning capacity and capability. Keywords tsunami; public response; warnings; 1960 INTRODUCTION With a magnitude estimated to be about 9.5 (Kanamori 1977), the earthquake on 22 May 1960 at 19.11 UT (Universal Time; 07.11 NZST 23 May) in southern Chile was the largest instrumentally recorded earthquake in the 20th century. It generated a tsunami that swept the shores of Chile and radiated out across the Pacific (ITDB/PAC 2004) (Fig. 1). There was major loss of life in Chile (about 800 from the tsunami) and, despite warnings being issued, in both Hawai‘i (61 deaths) and Japan (199 deaths). According to the Integrated Tsunami DataBase (ITDB/PAC 2004), the 1960 earthquake caused a large local tsunami with a maximum recorded run-up in Chile of 25 m. The tsunami resulted in US$550 million (US$3.6 billion in 2005 values) in damage in Chile. Another US$24 million (US$158 million in 2005 values) in damage occurred in Hawai‘i, and about US$500 000 to US$1 million (US$3.3–6.6 million in 2005 values) in damage on the United States west coast. In Japan, the waves were more than 6 m high, causing US$50 million ($US330 million in 2005 values) in damage. The absence of a Pacific-wide tsunami warning system at the time meant that the tsunami struck New Zealand without an official warning being issued. Fortunately, there was no loss of life. However, there was widespread damage to coastal facilities. The first waves of the tsunami arrived in the late evening of 23 May 1960, unobserved by most people. Nevertheless, the lives of several people in Hawke’s Bay, Gisborne, and Banks Peninsula were endangered, although no-one was seriously injured. The tsunami caused considerable minor damage to houses, boats, shops, wharves, jetties, port facilities, and boatsheds. Peak run-up heights ranged from 0.5 to 4 m throughout the east coast and at some places on the west coast of both the North and South Islands of New Zealand. The Chatham Islands, 1000 km to the east of Christchurch, were also strongly affected. The largest run-ups observed in New Zealand were in Gisborne (about 3.5 m), Napier (about 4 m), around Banks Peninsula (about 3 m), and in the Chatham Islands (about 3.5 m). The Earthquake and War Damage Commission received 69 claims from the 1960 tsunami, from Whangarei to the mouth of the Catlins River, with the greatest number coming from the Banks Peninsula and central Hawke’s Bay (EQC 1961). Total losses recorded were £5549 (about $193 000 in 2006 values) (EQC unpubl. files). These figures probably do not reflect the total losses but the real figure is likely to be modest nevertheless. The impact of the tsunami was actually reduced by some of the largest waves occurring within an hour or two of low tide over a significant part of the coast (G. Downes pers. comm. 2006, unpubl. New Zealand Tsunami Database). After the initial tsunami, a large aftershock occurred in Chile and fears about a tsunami from this event resulted in the broadcasting of a nationwide tsunami warning on 26 May 1960. Johnston et al.—Developing an effective tsunami warning system 107 1420 1410 1500 19 h 1400 1320 1400 18 h 20 h 1435 1520 1420 1220 21 h 1220 17 h 22 h 19 h 1020 1720 16 h North America Japan 1718 1210 1013 15h 1823 1721 14h Midway 09220840 1825 0816 0848 13h 1330 0802 1900 Hawaii 12h 1050 0756 2200 Wake 1033 1018 11h 1333 Johnston 0958 0657 10h 24 h 24 23 h 23 Guam 1130 1303 0500 1640 Truk 0450 1436 1320 0435 0440 Kwajalein Christmas Island 9h Canton 0903 8h 0140 7h 0924 0120 6h 0034 South 5h Pago Pago 0038 America 4h 0912 0733 2345 0842 Pacific Ocean 2240 2236 3h Australia 1135 16h 1015 2135 15h 1140 2115 0935 1040 0830 2h 0945 1500 2100 1h 14h 0710 0745 1911 13h New Zealand 12h 5m 0100 Rise Arrival time of initial rise or fall (GMT) Fall Wave front times for 1960 Chilean Tsunami Fig. 1 Travel-time map for the 1960 tsunami (modified from de Lange 1998; data from NOAA). This paper specifically focuses on the public and organisational response to the 26 May 1960 tsunami warning and discusses the methods of alert, the issue of “non-response” to warnings, the impact on utilities, post-tsunami public debate, and developing improved tsunami warnings since 1960. This discussion provides an analysis of public and government reactions to tsunami warnings and response, and looks at the lessons identified from the 1960 event. METHOD The principle method of data collection for the 1960 tsunami impact and evacuation story was a comprehensive analysis of articles in 38 newspapers (listed in Appendix 1) in print across New Zealand in May–June 1960. A systematic content analysis of the themes arising from the newspaper articles was undertaken. In addition, interviews were conducted between November 2004 and December 2007 with 18 eyewitnesses of the 1960 tsunami and who were evacuated. Oral accounts were collected from Akaroa (2), Blenheim, Christchurch (2), Lyttelton, Napier (2), Okains Bay, Opotiki, Paroa, Pigeon Bay, Te Awanga, and Whitianga (5). THE 1960 TSUNAMI WARNINGS After the initial tsunami, a large aftershock occurred in Chile (probably M7.5, 25 May 0834 UT listed in ITDB/PAC 2004), and fears about a tsunami from this event resulted in the broadcasting of a nationwide warning on radio in New Zealand. The sequence of events is as 108 Kōtuitui, 2008, Vol. 3 follows: a warning was received from Honolulu by the Air Department in Wellington at 11.43 a.m. (NZST) on 26 May that “a fresh, disastrous earthquake in Chile” had occurred and that a tsunami could possibly reach New Zealand within an hour ( Otago Daily Times , 27 May 1960). It was reported that “the appropriate departments and authorities were immediately notified, including the Marine Department, the Police, harbour masters, and the Government Emergency Organisation” ( Otago Daily Times , 27 May 1960).