Volcanic Hazards

StudyBlue printing of Volcanic Hazards html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; background: transparent; } body { line-height: 1; } blockquote, q { quotes: none; } blockquote:before, blockquote:after, q:before, q:after { content: ''; content: none; } /* remember to define focus styles! */ :focus { outline: 0; } /* remember to highlight inserts somehow! */ ins { text-decoration: none; } del { text-decoration: line-through; } /* tables still need 'cellspacing="0"' in the markup */ table { border-collapse: collapse; border-spacing: 0; } /* end RESET */ .header { min-width:800px; } .logo { padding:6px 20px 2px 20px; margin:0; font-size:25px; font-weight:bold; 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-moz-border-radius: 5px; -webkit-border-radius: 5px; } .print-button a:hover { background-color:black; } .theNote .content { width: 8.0in !important; margin: 5px auto; padding:20px; background-color:white; } .theNote .header { border-bottom: 1px dashed #C8C8C8; font-size: 17px; padding: 0 0 10px; line-height: 19px; color: #00ADE1; min-width:500px; } .theNote .body { font-size: 14px; line-height: 19px; padding: 10px 0; } .theNote{ padding:6px 0; clear:both; background-color: rgb(200,200,200); } .theNote h3{ color: rgb(100,100,100); } .theNote h1, .theNote h3{ background-color:white; padding:2px 20px; width:8.0in !important; margin: 0 auto; font-size: 15px; } .theNote h1{ padding-top: 10px; font-size: 15px; } .theNote h1:first-child{ font-size: 20px; } .theNote h3 { font-size: 14px; font-weight: normal; } #options { border: 3px double #ccc; padding: 5px 12px; margin: 10px 50px 10px 20px; float: left; } #info { border-top: 1px solid #ccc; padding-top: 5px; font-style: italic; } li { margin: 5px 10px 5px 25px; } ul li { list-style: disc; } ol li { list-style: decimal; } img { border: 0; } table { clear: both; width: 100%; border: 1px solid #c5c5c5; border-width: 1px 0; margin: 0; page-break-after: always; } table#page { page-break-after: auto; } td { text-align: center; font-size: 12px; border-bottom: 1px dashed #c5c5c5; height: 1.75in; width: 50%; padding-left: 15px; } .leftside { border-right: 1px solid #cccccc; padding: 0 15px 0 0; } .bottom td { border-bottom: none; } .clearfix { clear:both; line-height:1px; height:1px; } img { max-width:80%; max-height:150px; margin:20px; } @media print {.header { display: none; } .content .header{ display:inherit; } table { border: 1px dashed #bbb; border-width: 1px 0; } .theNote{ background-color:white; } } Volcanic Hazards tsunamis, equakes, hurricanes, and tornadoes, mass movements, floods, heatwaves, blizzards, droughts, volcanoes volcanoes- since ∼1600 ∼260,000 people have been killed Tambora 1815 AD- deadliest eruption 71,000-92,000 deaths Toba 74 AD- wiped out >99% of world's human population most active volcanoes on earth are not the biggest killers frequent eruptions tend to be small active volcanoes are closely monitored, better understood people who live near dormant volcanoes are more skeptical of danger frequency of disasters and number of victims are likely to increase in future vulnerability of societies will also increase major population centers on or near volcanoes are growing Pyroclastic flows extremely fast ∼150 m/s very hot ∼1000 C high impact forces people tend to live in valleys Surges even faster than flows can be even hotter than pfs pathways not confined to valleys Lahars - about 10% of all volcanic fatalities cause by these high velocities ∼100 km/hr high impact forces flow down valleys can flow ∼300 km from vents and submerge lowlands very frequent Sector collapse debris avalanches, pyroclastic flows volcanic tsunamis often occur without warning 25% of volcano fatalities in past 250 yrs have been from volcanogenic tsunamis Krakatau 1883- generated pyroclastic flows, impacted the sea- caused tsunami waves ∼37 m high --> 36,000 fatalities Tenerife: sector collapse or caldera collapse Volcanic gases toxic gases are directly responsible for ∼3% of volcano deaths since 1900, kill people every year lead indirectly to starvation and disease by poisoning crops- 40% of volcano deaths 1600-1982 Lake Manoun- 1984 39 people died (suffocation) Lake Nyos- 1986 1700 people died CO2 is denser than atmosphere, valley filling, displaces oxygen Airborne volcanic ash economic- planes abrasion of exterior forward facing surfaces on planes accumulation of ash in surface openings loss of visibility ingestion of ash into engines- melts, reforms as glass (ash is made of glass) Lava flows primarily economic/natural resources, property impacts Disaster mitigation includes all activities toward reducing risk of volcanic hazards and/or vulnerability catastrophes are often rooted in societal responses to eruptions volcanic hazard maps: first and most important step toward mitigating volcanic hazards forecasting and prediction of eruptions depends heavily on volcano monitoring Examples of hazard mitigation "sabo dams" and dikes- built to slow down or divert lahars drainage of crater lakes with tunnels degassing of CO2 from lakes (Nyos and Menoun) education and warning programs- distribution of videos showing hazards at Pinatubo installation of monitoring systems Icelandic fire hosing Case studies Nevado del Ruiz 1985 relatively small eruption, glaciers melted, generated lahars 23,000 people died night, no warning, poor monitoring, communication, planning 2 . Pinatubo 1991 2nd largest eruption in 20th century 1 million people in hazard region (in danger) 350 people died extensive monitoring, communication