Prediction of Volcanic Eruptions Vo s l c e Long Term Prediction a no Identify volcanoes and the frequency and style of their eruptions (a geological problem).

Establish probabilities of eruption, style and location for Part II individual volcanoes. Prediction Establish the level of risk based on historic and geologic Impact of eruptions record. Supervolcanoes E.g., for individual volcanoes: determine most likely routes Volcanoes in space for lahars, nuees ardentes, lava flows, etc., and avoid construction in those areas.

Hazard zones have been distinguished around Mt. Shasta Hazard zones have been distinguished around Mt. Shasta based on topography and past experience with eruptions. based on topography and past experience with eruptions.

Zone 1: areas likely to be affected Zone 1: areas likely to be affected Zone 1 most frequently. Most future flows Zone 2 most frequently. Most future flows from summit eruptions probably from summit eruptions probably would stay within this zone. would stay within this zone.

Zone 2: areas likely to be affected by lava flows erupted from vents on the flank of the volcano or that move into zone 2 from zone 1.

Short-term prediction Hazard zones have been distinguished around Mt. Shasta based on topography and past experience with eruptions. Based on the recognition of a pattern of events prior to Zone 1: areas likely to be affected previous eruptions. Zone 3 most frequently. Most future flows from summit eruptions probably Gas emissions: rates of emission and type of gas changes in would stay within this zone. some volcanoes.

Zone 2: areas likely to be affected Important gases include sulfur dioxide (SO2) and carbon by lava flows erupted from vents dioxide (CO ) on the flank of the volcano or that 2 move into zone 2 from zone 1. Changes in concentration may reflect movement of the Zone 3: areas likely to be affected magma up the vent. infrequently and then only by long lava flows that originate at vents in zones 1 and 2

1 Surface tilting: recognition of changes in the land Earthquakes: generated as the magma moves up the surface due to building pressure in the conduit. feeder conduit to the vent. A surface bulge appeared on Mt. St. Helens prior to its eruption. When viscous magma becomes stuck in the conduit strain April 8, 1980 energy builds as more magma tries to push out.

Movement takes place in a series of “jerks” as the rock material breaks. Each “jerk” produces an earthquake.

Magnitudes generally less than 5 M. April 26 May 2

The more earthquakes the further the magma has moved.

Mount Spurr, Alaska: The 1992 Eruption of Crater Peak Vent A combination of approaches is likely the key to short-term prediction.

Black bars: earthquake USGS frequency. Red lines: volcanic eruptions.

The impact of volcanic eruptions Volcanic Hazards Lava flows

Commonly destroy property in Hawaii and Iceland.

Damage limited to the vicinity in the immediate area of the volcano.

Fatalities rare due to slow speed of advancing lava flow.

2 Ash fall An ashfall 10 million years ago killed these rhinos that are preserved at Ashfall Fossil Beds State Historic Park, Nebraska. Extensive property damage and fatalities can result from heavy ash falls. Death was not by burial but by lung failure due to inhaling the ash. Significant ash in the upper atmosphere can circle the globe in a matter of weeks. More than 80 commercial jets have been damaged by flying through volcanic ash clouds.

Mt. St. Helens’ ash cloud

Pyroclastic flows Lahars can be the most devastating outcome of many volcanoes. Lahars are fast moving mudflows that can inundate urban areas that are nearby the eruption. A relatively small eruption of Nevada del Ruiz, Columbia, in 1985, generated a lahar when the volcano melted a 2.5 km2 area of snow and ice. Lahars can also dam rivers and which can lead to extensive flooding. Water and debris rushed down the slopes, picking up more debris along the way.

A 5 metre wall of water and debris Nuée ardentes destroy life and property in their paths. slammed into the town of Amero, 72 km from the volcano. 60 people, thousands of animals and fish, and hundreds of acres of lumber were destroyed by ash flows from Mt. St. Helens.

A Nuée Ardent killed 20,000 people when Mt. Vesuvius The lahar killed exploded and shed a pyroclastic flow across the village 28,700 people and of Pompeii in 79 AD. destroyed over 5,000 structures in the city.

3 Landslides

People and animals Landslides can be generated when a volcano collapses died instantly from the during an eruption. rushing cloud of hot gas and ash. During the Mt. St. Helens eruption 2.3 km3 of debris slid down the mountain at speeds up to 240 km/hr.

The slide traveled over 24 km and left a 45 m deep deposit.

350,000 years ago Mt. Shasta experienced a similar eruption and landslide that was 20 times greater than that of Mt. St. Helens.

Volcanic Gases SO2 emissions can have direct effects on life in the vicinity of a volcano. In addition to making magma more explosive, volcanic eruptions also include gases that can be deadly to all life. An eruption in 1783 of Laki Crater (Iceland) produced a sulfurous haze that lasted for 9 months and killed 75% of all livestock and 24% of the Icelandic population.

Volcanoes release more than 130 to 230 million tonnes of

CO2 into the atmosphere every year

Humans add CO2 at the rate of approximately 22 billion tonnes per year (150 times the rate of volcanic production)

CO , SO and CO are the most abundant of harmful gases. 2 2 Human CO2 production is equal to that if 17,000 volcanoes like Kilauea were erupting every year.

Mammoth Mountain is If the air that we breath has more than 10% CO2 it a relatively young becomes deadly because it displaces the Oxygen that we volcano that is emitting need for respiration. large volumes of CO2. Lake Nios, Cameroon, is a very deep lake within a volcanic crater.

The lake is so deep that hydrostatic pressure forces CO2 to remain at the lake bottom.

When the pressure of the CO2 exceeds a certain limit the Gas concentrations in the soil in gas rapidly bubbles up out of the lake and flows as an some areas near the mountain are invisible gas cloud down the adjacent slopes. high enough to kill trees and small animals. On August 61, 1986 such a gas release flowed 19 km suffocating 1,700 people along its route.

4 Tsunamis Lake Nyos 10 days after the 1986 eruption Caused by the displacement of seawater by eruptions of volcanic islands and submarine volcanoes.

Krakatoa (1883 eruption) killed 36,000 people by the tsunami, alone (the most deadly outcome of the eruption).

The fountain in the This is the newly forming background lifts CO 2 summit of Krakatoa, growing up to the surface so where the 1883 eruption blew that it no longer the top off of the original accumulates. volcano.

Global Climate Change A series of eruptions of Tambora (Indonesia) extruded up to 150 km3 of magma (solid equivalent), much of it into the Due to ash and gas that may spend years in the upper atmosphere. atmosphere; reduces incoming solar radiation.

SO2 from an eruption forms tiny droplets of sulfuric acid in the upper atmosphere.

The droplets significantly increase global albedo…..a negative radiative forcing that leads to cooling. Tambora (1815 eruption) was followed in 1816 by the “year without a summer”. Mt. Pinatubo (1991) released 22 million metric tons of SO 2 Average global temperature is estimated to have been and reduced the Earth’s average temperature by 0.5 reduced by 3 degrees Celsius. degrees Celsius in the year following the eruption.

In June of 1816 there was widespread snowfall throughout Approximately 260,000 people have been killed by volcanoes in the eastern United States. historic times…most by a handful of individual eruptions.

The normal growing season experienced repeated frosts as cold air extended much more southerly than normal.

Food shortages and starvation are attributed to the deaths of 80,000 people.

The global population was about 1 billion people in 1816.

Our current population is a little over 6 billion.

The 1816 fatality rate would have resulted in a death toll of nearly 500,000 people due to starvation.

5 Volcanic Explosivity Index

http://pubs.usgs.gov/publications/msh/comparisons.html

Deadly Historic Volcanic Eruptions An eruption in 1902 following the growth of a lava dome on the side Mt. Pelée of the mountain. (West Indes) VEI = 4

Lava domes are constructed of A stratovolcano along viscous lava and are prone to the Caribbean trench. collapse, unleashing a violent pyroclastic flow.

The nuée ardente that was generated when Mt. Pelée erupted swept 6 km downslope through the town of St. Vincent.

6 Tambora (1815) VEI = 7 Almost the entire population of 30,000 The largest eruption of historic time. people were killed within minutes of Greatest impacts from pyroclastic flows and inhaling the hot gases ash and gas eruptions. and ash. Approximately 150 km3 of ash was erupted with the explosions. There were only two survivors; one was in a 10,000 people were killed by bomb impacts, tephra falls and dungeon! pyroclastic flows.

By far the largest impact was on the Earth’s atmosphere.

The eruption plume reached 44 km above the earth, loading the stratosphere with ashes and gases.

Krakatoa (1883) VEI = 6

The concentration mercury On the Island of Rakata, Krakatoa was one of in ice cores from glaciers in 130 active volcanoes in Indonesia (the country Wyoming record a peak in with the most active volcanoes in the world). atmospheric mercury that corresponds to the Tambora eruption. The volcano had been inactive for almost 200 years prior to a series of small eruptions that began in 1883. The atmospheric impact caused the “year without a summer” along with 80,000 deaths due to famine and disease.

The volcanoes of Indonesia are due to the northeastward subduction Krakatoa began its eruptive stage on May 20, 1883 immediately of the Indo-Australian plate beneath the Eurasian plate. following a strong earthquake (no sensors were there to measure it).

Stratovolcanoes with a high probability of violent eruption. The first explosions were heard 160 km away and sent steam and ash upwards to a height of 11 km.

By August 11 three vents were active on the volcano.

On August 26 several loud eruptions took place over the course of the day sending dust and ash to over 25 km elevation into the atmosphere.

7 On August 27, four very large eruptions began at 5:30 am. The caldera collapsed with the explosion, from an original height of 450m above sea level to 250m below sea level. The last of the four was the largest and could be heard from Sri Lanka to Australia, up to 4,600 km from the volcano. The blast itself is thought to have ejected 20 km3 of tephra.

A 23 km2 area of the island was gone following the fourth eruption. The pyroclastic flow was experienced at sea as far as 80 km away.

Ships experienced hurricane force winds loaded with tephra and smelling strongly of Sulfur.

Burn-related fatalities were recorded up to 40 km away from the blast.

An estimated 4,500 people died from the direct effects of the blast.

The collapse of the caldera, combined with the explosion, generated Along low lying coasts of Java the waves washed 8 km onshore, a massive tsunami with a maximum height at landfall of 45 m. dragging people along with them as they washed back to sea.

The impact was greatest on the nearby islands. The tsunami was recorded as a small rise in sea level as far away as the California coast (20 hours after the fourth blast). Coral blocks up to 600 tons were washed ashore. An estimated 36,417 people were killed by the tsunami alone. This steamship was carried almost 2 km onto the land and dropped 10 m above sea level. Ash from the volcano fell to Earth as far away as 2,500 km downwind over the days following the eruption.

Ash and gases in the upper atmosphere led to a lowering of global temperature by several degrees.

Could Krakatoa have been the cause of humanity’s descent into the Dark Ages?

Anak Krakatoa (child of Krakatoa) has grown through Catastrophe: An Investigation into the Origins of the Modern World, ongoing volcanism where by David Keys, investigates the role of extreme climate change in a Krakatoa had existed. series of events in human history over the 6th and 7th centuries AD.

The fall of ancient super cities. It’s undergoing a constructive phase of mild strombolian and The sharp decline of ancient civilizations: Persia, Indonesia, the Nasca vulcanian eruptions. culture of South America, and southern Arabian civilizations.

The breakup of the Roman Empire and the formation of many nation states.

Restructuring that led to a new united China. But, there’s a little more to this story…..

8 This was also the first time that the Bubonic Plague spread through much of the known world. Keys suggested that a major impact of an asteroid or comet or a major volcanic eruption might have accounted for the global climate change This epidemic had hit Alexandria in 541 AD after spreading from east that led to the onset of the dark ages. Africa. No major impact structures are known to have formed over the required The disease is believed to have killed 900,000 people over a 100 year time so investigations focused on a volcanic eruption. period. Ken Wohletz of the Los Alamos National Laboratory took on a These events all appear to be linked to a major climatic change that took collaboration to try to find a volcanic source of such a major eruption. place in 535 AD. He summarizes some of his ideas at: A written description of the time describes a major atmospheric event: http://www.ees1.lanl.gov/Wohletz/Krakatau.htm “The Sun became dark, and its darkness lasted for about 18 months. Each day, it shawn for about four hours and still this light was only a feeble shadow.”…. John of Ephesis Historical evidence of calamity in both the northern and southern hemispheres suggested a near-equator eruption and his search focused on Indonesia, a major volcanic hot-spot.

Wohletz’s work identified thick pyroclastic deposits in Indonesia, near Wohletz describes in some detail a hypothetical eruption of Krakatoa that Krakatoa, that were dated to be about 1500 years old. would have produced such a caldera.

Further investigation showed a possible volcanic caldera where Krakatoa now resides.

As the volcano begins to erupt the Sunda Straits do not exist as the land The onset of eruption was only of steam due to water entering the had been built up by volcanic activity over thousands of years. vent(s), blowing rocks and ash upward with it.

Phreatic eruptions are due to the boiling of groundwater by heat due to the magma chamber as magma slowly rose towards the surface.

9 Once at the surface the 900 degree Celcius magma, charged with gas With the ultra plinean eruption the caldera would form as it collapsed and and water vapor would cause an ultraplinean (very explosive) eruption. seawater would rush into the magma vent. Material would be ejected at a rate of 100 to 1000 million kg/second, Water would flash into vapor causing a giant phreatic eruption to eject much of it falling in the vicinity, the remainder rising into the stratosphere debris and vapor upwards and cause pyroclastic flows across the ground. where it would travel around the world.

The collapse of such a caldera would involve the eruption of 200 km3 of magma; about 75 km3 of ash would be injected into the atmosphere.

In addition, another 150 km3 of water would be ejected as 200,000 km3 of water vapor, much of which would remain for some time in the upper atmosphere as ice crystals (increasing global albedo).

The model suggests that the Earth would have cooled by 5 to 10 degrees Celsius for a period of 10 to 20 years.

Such an event would: Super Volcanoes While not defined officially, lets say any eruption that ejects 1000 km3 or more of pyroclastic material (i.e., VEI 8 or more). Modify weather patterns extensively. According to M.R. Rampino super eruptions take place, on average, Cause crop-failure world-wide. every 50,000 years. Three of the best known eruptions are compared below. Result in poor nutrition that would increase risk to disease.

Decrease populations and lead to political stress that would result in extensive social change.

Possibly leading to the Dark Ages.

10 Toba: the world’s largest Quaternary caldera. Today Toba is a caldera or depression that is occupied by Lake Toba.

It is 100 km long and 30 km wide.

Toba last erupted about The Australian Plate is subducting 75,000 years ago with the beneath the Eurasian plate at a rate largest eruption of the last 2 of 6.7 cm/yr. million years.

Three eruptive events have been The eruption ejected 2,800 cubic km of material and the pyroclastic recognized. flows covered an area of at least 20,000 square km.

840,000 years ago In the immediate vicinity of the volcano ash deposits reach 600 metres in thickness 500,000 years ago

74,000 years ago Ash fall from the eruption covers an area of at least 4 million square km; half the area of the continental United States. Each producing a caldera. Global cooling is estimated at between 3 and 5 degrees Celsius with regional cooling of 15 degrees C.

Samosir Island, rising 750 m above Tropical plant life would have been all but eliminated the lake, is a dome built from lava following the last eruption. Temperate forests would loose 50% of all trees.

It is estimated that the growing population of homo sapiens (i.e., us) was Yellowstone Caldera reduced from 100,000 individuals to as few as 3,000 individuals (97% of Known for its hot springs and geysers, all humans were lost!). Yellowstone National Park, is likely the most popular super volcano in the This reduction had been estimated for approximately the time of Toba’s world. eruption on the basis of genetic studies and is termed the “human population bottleneck”. The park sits on an active caldera that rises and sinks in response to magma movement and pressure fluctuations within the Earth.

Over recent years the surface has risen by as much as a metre and sunk back by 1/3 of a metre.

Thousands of small earthquakes are produced as earth surface moves.

11 The caldera and its magma chamber are due to a hot spot in the mantle The magma chamber is only 5 to 13 km below the land surface. that has moved several hundred kilometres over the past 12.5 million years. The movement is due to the drift of the north American continent over The caldera is 80 km the hot spot. long and 50 km wide.

Ancient, inactive calderas mark the path of the hot spot.

The current caldera was formed with an eruption 640,000 years ago (the Eruptions appear to have a 600,000 year period (that long between Lava Creek Eruption). eruptions) so we’re overdue for another one.

This eruption ejected 1,000 km3 of pyroclastic debris. Previous eruptions spread ash over thousands of km2 across the US.

An earlier eruption (the Huckleberry Ridge Eruption, 2 million years ago) ejected 2,500 km3 of pyroclastic debris.

A smaller eruption happened 1.3 million years ago, releasing 280 km3 of debris.

Heightened monitoring of the Yellowstone Caldera in recent years has led to media concern of an impending eruption. Volcanoes in Space

Government officials and geologists indicate that there have been no clear indicators of high risk at this time.

If such an eruption were to take place, North America and the rest of the world could experience another “Dark Ages”.

NASA

12 Venus has over 100,000 shield volcanoes. Mars Volcanoes on mars: giant volcanoes are present, far larger than Sapas Mons anything on Earth. Anemone 1

120 km http://volcano.und.edu/vwdocs/planet_volcano/venus 40 km

Ceraunius Tholus and Uranius Tholus Craters on the volcanoes suggest that they may not have been active for millions of years.

Not erupting at present but it may still erupt in future. Olympus Mons: 24 km high, 500 km across, with a 6 km high cliff at its base.

13 Olympus Mons is thought to be located over a hot spot but the crust is stationary so that it grew to greater size than any Earth volcano.

Volcanoes on Io (a moon of Jupiter)

Volcano Pele

Volcano Prometheus

14 Babbar Patera Volcano (300 km across)

15