KNOWLEDGE BOX 4.4 THE RING OF FIRE

The Ring of Fire, also called the Circum- Pacific Belt or Pacific Ring of Fire, is a horseshoe- shaped seismically active belt of earthquake epicentres, volcanoes and tectonic plate boundaries that fringe the Pacific basin (see Figure 4.4).

FIGURE 4.4 The Ring of Fire

Source: Adapted from Encyclopaedia Britannica (http://media- 1.web.britannica.com/

eb- media/57/5457- 050- 84F0FBED.jpg).

What are the known risk factors associated with adverse health outcomes?

The activity level of a volcano, such as the frequency of emissions of harmful gases and volcanic mudfl ows between eruptions, is a key factor that indicates the future behaviour of the volcano and the current impact it has on neighbouring commu-nities. While there are currently no standardised tools to estimate the population risk from being exposed to volcanic activities, the Smithsonian Global Volcanism Program (GVP) is a method of assessing the volcanic hazard risk by scoring erup-tion characteristics, such as type of lava fl ow, maximum output capacity, eruperup-tion history and volume of surrounding glaciers and snowcaps. It is worth noting that most of the active volcanoes in the twenty- fi rst century are in highly dense urban areas, such as Tokyo, Mexico City, Jakarta and Manila. For a location with a high population density, a good early warning system and evacuation plans are vital to mitigating the impact of volcanic eruptions. Countries typically classify volcanoes into “high”, “medium” and “low” risk based on the volcanoes’ eruption history, number of people affected and potential economic losses.

What are the health impacts of volcanic eruption?

Volcanic eruptions result in the highest mortality rates when compared with other types of natural disasters. This high level of mortality is due to the risks of pyro-clastic fl ows , which can result in high levels of deaths, fatal injuries and severe

Volcanoes are associated with the movements of tectonic plates along this belt;

thus, the belt is called the “Ring of Fire”. An overwhelming majority of the world’s strongest earthquakes and approximately 75% of the world’s volcanic activities occur within the Ring of Fire. Ecuador, Papua New Guinea and the Philippines are examples of countries that are located in the active volcano regions. Volcanoes along the Ring of Fire are not equally distributed. Indone-sia is the country with the highest number of active volcanoes in the world, followed by Japan, the United States and Chile. The Ring of Fire has been the setting for several of the largest earthquakes in recorded history, including the Chile earthquake of 1960, the Alaska earthquake of 1964, the Chile earth-quake of 2010, the Japan earthearth-quake of 2011 and the earthearth-quake that gener-ated the devastating Indian Ocean tsunami of 2004.

Other than the Ring of Fire, areas prone to volcanic eruptions include “hot spots” in the ocean where the earth’s crust is weak and island chains that are formed by the erupted magma, like the one across the North and South Atlantic Oceans.

Sources: USGS (2015), Ring of Fire (n.d.).

burns. Pyroclastic fl ow is a mass of hot volcanic ash, lava fragments and gases that erupt from a volcano and move rapidly down its slope. It can travel more than 300 kilometres per hour and may reach temperature as high as 600 ° C to 900 ° C (Jay, 2006; Hogan & Bearden, 2007). The fragmentary material emitted from a pyroclastic fl ow is called tephra (Hansell et al., 2006). Ashes are tephra frag-ments that are less than 2 mm in size. Ashfall that follows an eruption, particularly wet ash, can damage buildings and contaminate water sources. Heavy ashfall can cloud the sky, leaving people living in complete darkness during the day. The free silica and high iron content of ash irritates the upper and lower respiratory airways, eyes and skin. High levels of airborne ash (daily average total suspended particles (TSP) of 3,000–33,000 μg/m3) can result in a two- to threefold increase in hospital admissions and a three- to fi vefold increase in emergency room visits for respiratory- related illnesses (Baxter, Ing, Falk, & Plikaytis, 1983). Lapilli are tephra fragments between 2 and 64 mm in size, while lava bombs or blocks are those larger than 64 mm (Jay, 2006). The ejection of lava bombs can cause severe head injuries, burns and blunt trauma . Volcanic gases , such as sulphur diox-ide, carbon dioxide and hydrogen fl uordiox-ide, also impose signifi cant health hazards.

Sulphur dioxide can be irritating to respiratory airways, eyes and skin. Hydrogen fl uoride can also generate the same effect, but when it is ingested by animals, it will produce fl uorosis and cause death. Breathing carbon dioxide with a concen-tration greater than 20% can also cause unconsciousness and asphyxiation in humans (Baxter, 1990).

What are the responses needed?

Volcanic events are relatively uncommon compared to other natural disasters. The important health problems to consider when responding to the health needs after volcanic eruptions are the provision of health care for burns, injuries, inhalation and respiratory trauma from exposure to ash and toxic gases. Securing all the lifeline infrastructure and managing post- impact health risks are also crucial.

Health risks include mucosal (eye) irritations and skin and respiratory tract burn injury from volcanic ashfall, pyroclastic fl ows, mudfl ows, tsunamis and vol-canic earthquakes. Toxic gases may also cause suffocation and respiratory diseases.

Volcanic eruptions cause loss of infrastructure, agricultural land and property and economic loss. Indirect health impacts from relocation and the loss of homes are more likely to cause greater adverse outcomes than direct injuries from falling rocks and burns. Surveillance systems to detect volcanic movements and early warning systems are regarded as the most effective ways to prevent the adverse impacts of this type of disaster.

In summary, volcanic activities are common in places located along the Ring of Fire. Volcanic eruptions with pyroclastic fl ows of ash and lava bombs result in a high mortality rate and respiratory problems. Volcanic ash can affect people miles away from the volcano. These events are likely to affect neighbouring communities by emitting hazardous gases and particles.

Meteorological hazard: tropical cyclone/hurricane/typhoon While storms refer to a wider variety of disturbances in the atmosphere and are often accompanied by strong wind, rain, snow, thunder and lightning, hail, fl ying sand or dust, t ropical cyclones are meteorological hazards which are character-ised by low atmospheric pressure, spiral rain bands and strong winds of 64 knots or more. Depending on the location, these hazards are named differently. Tropical cyclones occurring in the Indian Ocean and South Pacifi c are called cyclones , those originating in the Western Atlantic and Eastern Pacifi c are called hurricanes and those happening in the Western Pacifi c are called typhoons (CRED, 2009).

Tropical cyclones may bring heavy rain, strong winds or even large storm surges.

Secondary disasters, such as mudslides and landslides, may occur near mountainous areas. Landed tropical cyclones can also generate tornadoes that may bring further health and socio- economic risks to the community.

How is it reported?

A number of measuring scales are used regionally to describe the intensity and impact of tropical cyclones. The World Meteorological Organization (WMO) rec-ommends the relevant scale according to the geographic location of the oceanic basin and the maximum speed of sustained winds (see Table 4.2).

TABLE 4.2 Scales for measuring the intensity of cyclones in various oceanic basins

Region Scale

Atlantic and Eastern Pacifi c Oceans Saffi r- Simpson Hurricane Scale Western Pacifi c Ocean RSMC Tokyo’s Tropical Cyclone

Intensity Scale

North Indian Ocean India Meteorological Department

Tropical Cyclone Intensity Scale Southwestern Indian Ocean Southwest Indian Ocean Tropical

Cyclone Intensity Scale Source: WMO (n.d.).

What are the known risk factors associated with adverse health outcomes?

Vulnerability to a tropical cyclone depends on location and infrastructure. Popula-tions residing in low- lying coastal areas face the highest risk of an adverse impact from tropical cyclones. These coastal areas are particularly vulnerable to storm surges and heavy rain, which may cause coastal fl ooding or temporary displace-ment. People residing near rivers are also at risk of fl ash fl oods. Infrastructure factors that increase vulnerability include poor building design, lack of or ineffective early

warning systems, insuffi cient evacuation time and inaccurate perceptions of risks and safety. Vulnerability to cyclones is further increased by population growth, urbanisation, increasing coastal settlement and global warming (Doocy, Daniels, Murray, & Kirsch, 2013). Since the twentieth century, populations in Southeast Asia, the Western Pacifi c and the Americas have faced increasing risks posed by cyclones, typhoons and hurricanes.

What are the direct health impacts of a cyclone?

A tropical cyclone could cause events such as fl ooding, storm surges, landslides and infectious disease outbreaks. As information and records in less- developed countries are often inaccurate or inaccessible, the true health impacts of a cyclone are hard to measure and only partially documented (see also Case Box 4.2). Clinically, the most common health conditions observed after a cyclone are minor injuries, including lacerations, blunt trauma and puncture wounds

CASE BOX 4.2 TYPHOON HAIYAN IN THE PHILIPPINES Typhoon Haiyan hit the Philippines on 8 November 2013. It affected nine regions, 44 provinces and nearly 600 municipalities. Its economic impact is estimated to be about $700 million in damage to agriculture and infrastructure alone.

Key fi gures

• 14.1 million affected people

• 4.1 million displaced

• 6,190 deaths

• 1,785 people missing Shelters

• More than 1.1 million houses damaged, half of which were completely destroyed

• Lack of relocation sites

• Only 2% of displaced population housed at 381 temporary evacua-tion sites

• 3,993,753 displaced people living outside evacuation centres Food security

• 30% of the affected population facing food insecurities and dependent on food assistance for survival

• Food security and agriculture cluster targeting 3 million people in need of food assistance

FIGURE 4.5 The aftermath of Typhoon Haiyan in the Philippines

Source: Photo by Trocaire/CC BY 2.0 (https://commons.wikimedia.org/wiki/

File:Tacloban_Typhoon_Haiyan_2013- 11- 14.jpg; https://creativecommons.org/

licenses/by/2.0/deed.en).

Water

• The majority of the affected population have limited access to safe drink-ing water

• Water supply damage and contamination: Many water systems destroyed, and over half of the surface resources and half the groundwater contami-nated by polluted waters from industry activities, agricultural chemicals, and domestic waste and septic systems, increasing the threat of disease outbreaks

Source: Joint UNEP/OCHA Environment Unit (2014).

The 2013 Super Typhoon Haiyan in Asia was the third Category 5 typhoon to strike the Philippines since 2010, and tore through Tacloban in the province of Leyte, affecting about 13 million people. Figure 4.5 shows a devastated Tacloban after Typhoon Haiyan. Merely four weeks earlier, the Super Typhoon Usagi landed in southern China and affected more than 2.7 million people.

With an increasing number of extreme weather events due to climate change (from 99 in 1980 to 269 in 2011), Asia is likely to be hit by stronger typhoons more frequently in the coming decades. The 2013 World Disaster Report iden-tified access to information and technology as one of the major challenges to a community’s disaster preparedness, survival, and recovery.

caused by collapsed buildings and falling debris. Eighty per cent of cyclone- related injuries are found in the lower limbs (Shultz, Russell, & Espinel, 2005).

Asphyxiation, trauma and electrocution are commonly observed in a tropical cyclone disaster. Post- traumatic stress disorder and depression have also been observed after large- scale tropical cyclones. However, the true human impact is hard to measure. A tropical cyclone can cause secondary disasters, like fl ooding, storm surges and landslides, leading to additional deaths and injuries. Unless cyclones are related to fl oods or sea surges, they usually cause relatively few deaths and injuries.

Of note, although outbreaks of infectious disease rarely occur after major hur-ricanes and associated fl oods, waterborne and food-borne diseases can result from contami nation of water and food crops. Displacement of people to crowded shelters can lead to transmission of infectious respiratory disorders. Standing water can pro-mote mosquito breeding and in turn lead to vector-borne diseases. Damaged wires can also cause electrocutions and fi res.

What are the response needs?

Cyclones are characterised by strong winds and precipitation. They could result in high numbers of injuries and massive destruction of infrastructure. Injuries are the most common direct health effect of a tropical cyclone. Victims need wound management, antibiotic treatment and tetanus prophylaxis. Health care facilities located in at- risk areas should take precautions by ensuring build-ing safety, preparbuild-ing a contbuild-ingency electricity supply and practisbuild-ing evacuation protocols.

What are the public health needs after cyclones/typhoons/

hurricanes?

Effective response after storm disasters requires that responders address (1) the basic survival needs of affected people, including food, safe water, sanitation, shelter, health care and access to necessary information, and (2) disaster- related injuries with sound management: antibiotic treatment, where indicated; tetanus prophylaxis and measures against other health risks. Specifi cally, environmental health risks should be anticipated and minimised through measures such as ensuring adequate supplies of safe food and water and controlling disease vectors. Health care facilities should have contingency electricity and water supplies. Regularly updated evacuation pro-tocols and emergency drills are essential to ensure the relevancy of the emergency plans and familiarity of community residents with these important procedures. Last but not least, access to information is critical for preparedness, survival and recovery after community disasters (see also Knowledge Box 4.5 and Case Box 4.3).

Although media coverage of cyclones and their aftermath often focuses on the immediate ravages, injuries, deaths and economic loss, typhoons and hurricanes

also bring less visible long- term consequences for health. Well- organised lon-gitudinal data and comprehensive surveillance information are often limited in low- income settings, and, as a result, information about the long- term physi-cal and mental health consequences of cyclones and the ensuing fl oods for the population is not available to guide evidence- based disaster emergency prepared-ness and response planning. Research agendas at the community level should identify predictors of and barriers to the ability of households and communi-ties to respond to disaster warnings, and also assess the effectiveness with which information about health responses after a disaster is delivered. Research also needs to explore the best way to organise surveillance data and systems to reduce post- disaster health risks. How to mobilise community volunteers to engage in evidence- based, post- disaster health action remains a major operational challenge for governments, frontline workers and academics, and gaps in technical knowl-edge must be tackled.

Tropical cyclones are likely to adversely affect populations in low- lying coastal areas. For disaster mitigation, solution should target modifi able risk factors, such as poor building design, lack of early warning systems, inadequate disaster pre-paredness, insuffi cient time for evaluation and inaccurate perception of risks and safety. Improved weather forecasting systems with community- wide, early warn-ing systems and continuous public education may mitigate the adverse health impact by heightening community risk perception and people’s responsiveness to warnings.