Introduction to Geohazard

generalized term for continental crust

"granitic"

How to calculate %Ionic Character (IC):

%IC = {1-exp[(-0.25)(E1-E2)^2 ]} x 100 where: E1= electronegativity of element 1 E2= electronegativity of element 2

General Characteristics of Mantle

- Thick (~2900 km) relative to the radius of Earth (~6370 km) and constitutes ~83% of Earth's total volume. -contains an average of approximately 40-45% SiO2 which means it has an ultrabasic composition. -contains number of sublayers (upper mantle and transition zone, and lower mantle) -distinguished from the crust by being very rich in MgO (30-40%) and to a lesser extent, in FeO

Mineral transformations within the transition zone (Hefferan & O'brien, 2010)

---> 1. Olivine (Mg2SiO4) 2. Wadleysite/Beta Spinel (Mg2SiO4) @ 410 km depth 3. Ringwoodite (Mg2SiO4) Garnet (Mg2SiO4) @Transition Zone 4. Perovskite [(Mg,Fe,Al)SiO3] & Periclase (MgO) @660 km depth

What is a element?

-Fundamental building blocks -smallest matter that can't be broken down

Responsibilities of Scientists and Engineers to Assessments, Predictions, and Warnings.

-Hazard Assessment -Prediction -Reduction of Risk -Early Warning -Communication

Responsibilities of Public Officials to Assessments, Predictions and Warning.

-Risk Assessment -Planning and Code Enforcement -Early Warning -Response -Communication

The effectiveness of a warning depends on:

-The timeliness of the warning. -Effective communications and public information systems to inform the public of the imminent danger. -The credibility of the sources from which the warning came.

Responsibilities of Citizens to Assessments, Predictions and Warning.

-Understanding of Hazards -Understanding of Early Warning Systems -Communication

Risk involves the following

-hazard assessment. -location of buildings, highways, and other infrastructure in the areas subject to hazards. -potential exposure to the physical effects of a hazardous situation. and -the vulnerability of the community when subjected to the physical effects of the event.

Major minerals in the mesosphere (660km to ~2900km depth)

-perovskite and periclase [(Mg,Fe)O] -Magnesiowustite [(Mg,Fe)O] -Limenite [(Fe, Mg) TiO2] -Stishovite (SiO2) -Ferrite [(Ca, Na, Al) Fe2O4]

Hazard Assessment consists of determining the following:

-when and where hazardous processes have occurred in the past. -the severity of the physical effects of past hazardous processes (magnitude). -the frequency of occurrence of hazardous processes. -the likely effects of a process of a given magnitude if it were to occur now; and -making all this information available in a form useful to planners and public officials responsible for making decisions in event of a disaster.

examples of states of matter

1. Gold (solid) 2. Mercury (liquid) 3. Oxygen (gas)

Give example of Earth's heat sources

1. heat from when the planet formed and accreted, which has not yet been lost 2.frictional heating caused by denser core material sinking to the center of the planet 3. heat from decay of natural occuring radioactive elements/nuclides

All other elements percentage

1.5%

the outer core is inferred to be a liquid with density:

10-12 g/cm3

Examples of long lived radioactive isotopes

235U (Uranium), 238U, 232 TH (thorium), and 40K (Potassium)

What is a system?

A collection of related objects and the processes relating these objects

Acceptable risk is a risk exposure that is deemed acceptable to an individual, organization, community or nation. Acceptable risks are defined in terms of the probability and impact of a particular risk.

Acceptable Risk

It is the ability of a population to cope and/or prepare to the effects or impacts of a particular hazard.

Adaptive Capacity

a gain of electrons, resulting in a negative (-) charge

Anions

These are hazards that occur as a result of human interaction with the environment. They include Technological Hazards, which occur due to exposure to hazardous substances, such as radon, mercury, asbestos fibers, and coal dust.

Anthropogenic Hazards

Solid but mobile layer

Asthenosphere

These are also natural hazards but processes operating in the atmosphere is mainly responsible

Atmospheric/Hydr0meteorologic Hazards

the make-up of solid matter on Earth:

Atoms --> Elements --> Compounds ---> Minerals ---> Rocks (From smallest to largest)

Percent Silica content of Oceanic Crust and Oceanic Crust, sequentially;

Averages ~50% SiO2 & Averages ~60% SiO2

Involves the circulation and exchange of elements and minerals within the ecosphere and its environment. The global cycle of carbon, oxygen, hydrogen, and nitrogen are among the examples that fall under this category.

Biogeochemical Cycle

a loss of electrons, resulting in a positive (+) charge

Cations

(1) Energy may transfer into and out of the system, but not mass e.g. the Earth as a whole is closed

Closed System

Discontinuity between upper and lower crust

Conrad Discontinuity

It is the transition zone between SIAL and SIMA.

Conrad Discontinuity; SIAL indicates the composition of Silica and Aluminum whereas SIMA indicates the composition of Silica and Magnesium.

electrons are shared between atoms. generally strong bonds (e.g., diamond, pure C)

Covalent bonding

DENR - MGB

Department of Environment and Natural Resources - Mines and Geosciences Bureau

PHIVOLCS

Department of Science and Technology - Philippine Institute of Volcanology and Seismology

A serious disruption of the functioning of a community or a society at any scale due to hazardous events interacting with conditions of exposure, vulnerability and capacity, leading to one or more of the following: human, material, economic and environmental losses and impacts (UNDRR, 2020).

Disaster

Our knowledge of the deep mantle continues to expand, largely based on anomalous seismic signals deep within Earth. These are particularly common in a complex zone near the core- mantle boundary called

D″ layer.

Examples of Natural Hazards

Earthquakes, Volcanic Eruptions, Floods, Mass Wasting, Tsunami, Subsidence, Drought, Typhoons, Tornadoes, and Asteroid Impacts.

Examples of Geologic Hazards.

Earthquakes, Volcanic Eruptions, Tsunami, Mass Wasting and Floods. (Might be common in the Philippines?)

the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond.

Eletronegativity

True or False. Geologic processes do not affect every human on the Earth at all times but are most noticeable when they cause loss of life or property.

False. Geologic processes AFFECT every human on the Earth at all times but are most noticeable when they cause loss of life or property.

True or False. Hazard Assessment and Risk Assessment are synonymous.

False. Hazard Assessment and Risk Assessment are NOT synonymous.

True or False. The Earth's mantle, including the transition zone, consists primarily of peridotite, a mafic igneous rock.

False. The Earth's mantle, including the transition zone, consists primarily of peridotite, an ultramafic igneous rock

True or False. The Oceanic Crust is thick and the depth to the Moho Averages 10-20 km.

False. The Oceanic Crust is thin and the depth to the Moho Averages 5-7km.

True or False. The risk from natural hazards, while it cannot be eliminated, can, in some cases be understood in such a way that we can minimize the hazard to humans, and thus maximize the risk.

False. The risk from natural hazards, while it cannot be eliminated, can, in some cases be understood in such a way that we can minimize the hazard to humans, and thus MINIMIZE the risk.

used synonymously with prediction and other times it is not. In the prediction of floods, hurricanes, and other weather-related phenomena the word forecast refers to short-term prediction in terms of the magnitude, location, date, and time of an event In the prediction of earthquakes, the word forecast is used in a much less precise way - referring to a long-term probability that is not specific in terms of the exact time that the event will occur.

Forecast

are geological processes or phenomenon that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage (UNISDR, 2009).

Geohazard

developed by Victor Goldschmidt, is a geochemical classification which groups the chemical elements according to their preferred host phases into lithophile (silicate loving), siderophile (iron loving), chalcophile (sulfur loving), and atmophile (gas loving).

Goldschmidt classification

Example of Van der Waals bonding

Graphite

Discontinuity between lower mantle and outer core

Gutenberg Discontinuity

a process/phenomenon that may pose a threat to human lives and/or properties

Hazard

Elevation of Continental Crust

Higher surface elevations; mostly emergent above sea level

Density of Oceanic Crust

Higher; less buoyant (Average 2.9-3.1 g/cm3)

detected subducted lithosphere that had sunk all the way to the D″ layer and may be responsible for the anomalously fast velocities

Hutko et al. (2006)

It is primarily a solid ball with a radius of about 1,220 km (760 mi).

Inner core

consists primarily of Fe (~85%) with smaller, but significant amounts of Ni (~5%) and lighter elements (~8-10%) such as O, S and/or H. Has less O, S, and H than in the outer core.

Inner core

electrons are transferred between atoms forming attracting ions (e.g., NaCl). an orderly arrangement of oppositely charged ions. bonds are moderately strong (salt dissolves in water)

Ionic Bonding

The core is composed of two materials

Iron and nickel

(1) No energy or matter leaks out of system & none comes in. e.g. the Universe as a finite entity

Isolated system

a subset of the lanthanide series of the rare earth elements, which are themselves a special set of transition metals.

LREE (light rare earth elements, light-group rare earths,)

This model has two largely disconnected convective layers. A dynamic upper layer driven by descending slabs of cold oceanic lithosphere and a sluggish lower layer that carries heat upward without appreciably mixing the layer above.

Layer cake model

Discontinuity between outer and inner core

Lehmann Discontinuity

Elevation of Oceanic Crust

Low surface elevation; mostly submerged below sea level

Density of Continental Crust

Lower; more buoyant (2.6-2.9 g/cm3

electrons drift around from atom to atom (e.g., copper, gold, silver). good conductors of electrical current. generally weaker, less common than other bonds

Metallic Bonding

Discontinuity between lower crust and upper mantle

Moho/Mohorovicic Discontinuity

NDRRMC

National Disaster Risk Reduction and Management Council

a natural phenomenon that might have a negative effect on humans and other animals, or the environment

Natural Hazards

Do hazards always lead to disaster?

No, when there is harm to life and property of humans, the hazard is termed a disaster. All disasters are hazards, but all hazards are not disasters.

(1) Matter and energy may flow into and out of the system freely i) energy and mass transfer functions. (2) Steady State System o (special type of open system) balance between input and outflow.... INPUT + OUTPUT

Open system

may be slices of ocean crust thrust onto continental margins

Ophiolites

These are hazards that may occur naturally, but don't fall in to either of the categories mentioned.

Other Natural Hazards. Examples of it are Insect Infestations, Disease/Viruses, and Wildfires

is a fluid (liquid) layer about 2,260 km (1,400 mi) thick, composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. begins approximately 2,889 km (1,795 mi) beneath Earth's surface at the core-mantle boundary and ends 5,150 km (3,200 mi) beneath Earth's surface at the inner core boundary

Outer core

Element abundances in the crust

Oxygen (46.6%) Silicon (27.7) Aluminum (8.1%) Iron (5.0%) Calcium (3.6%) Sodium (2.8%) Potassium (2.6%) Magnesium (2.1%) All others (1.5%)

Most abundant element in the crust

Oxygen at 46.6%

PAGASA

Philippine Atmospheric Geophysical & Astronomical Services Administration

A statement of probability that an event will occur based on scientific observation (Nelson, 2006). Such observation usually involves monitoring the process in order to identify some kind of precursor event(s) - an an anomalous small physical change that may be known to lead to a more devastating event

Prediction

Occur as a result of the process itself. For example, water damage due to a flood, and collapse of buildings due to an earthquake, landslide, typhoon, or tornado.

Primary Effects

Two types of Hazardous process of all types.

Primary Effects, Secondary Effects and Tertiary Effects

Rainfall Warning by PAGASA

Red Warning - walang humpay na pagulan sa loob ng i oras at susunod pang 2 oras (Lumikas) Orange Warning - Matindi ang pagulan sa loob ng 1 oras at susunod pang 2 oras (Alerto) Yellow Warning - Malakas ang pagulan sa loob ng 1 oras at susunod pang 2 oras (Monitor)

Discontinuity between upper and lower mantle

Repetti Discontinuity

Risk remaining after risk treatment. After you identify the risks and mitigate the risks you find unacceptable (i.e. treat them), you won't completely eliminate all the risks because it is simply not possible - therefore, some risks will remain at a certain level, and this is what residual risks are.

Residual Risk

The potential loss of life, injury, or destroyed or damaged assets which could occur to a system, society or a community in a specific period of time, determined probabilistically as a function of hazard, exposure, vulnerability and capacity (UNDRRR, 2020)

Risk

Quantitative Equation of Risk

Risk = (probability that the hazard will happen) x (expected impacts)

Involves not only the assessment of hazards from a scientific point of view, but also the socio-economic impacts of a hazardous event.

Risk Assessment

A solid aggregate (mixture) of minerals

Rock

Geosphere

Rock Cycle; rocks are constantly forming, changing and reforming.

occur only because a primary effect has caused them. For example, fires ignited by earthquakes or volcanic eruptions, disruption of electrical power and water service as a result of an earthquake or flood, and flooding caused by a landslide moving into a lake or river.

Secondary Effects

Lower mantle & Upper mantle

Solid

Related to the spatial aspects of hazard; the tendency of an area to undergo the effects of hazards (Encyclopedia of Natural Hazards, 2013). Degree to which the elements at risk are likely to experience hazard events of different magnitudes/scales.

Susceptibility

are long-term effects that are set off as a result of a primary event. These include things like loss of habitat caused by a flood, permanent changes in the position of river channel caused by flood, crop failure caused by a volcanic eruption etc.

Tertiary Effects

Thickness of Continental Crust

Thicker; Average 30 km thickness and Up to 80 km under mountains

Thickness of Oceanic Crust

Thinner; Average 5-7 km thickness and Up to 15 km under islands

is part of the Earth's mantle and is located between the lower mantle and the upper mantle, between a depth of 410 and 660 km (250 to 400 mi).

Transition Zone

Layers of Earth's Material

Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere.

True or False. Continental crust is generally much thicker than oceanic crust.

True

True or False. Oceanic crust is young relative to the age of the Earth.

True

True or False. Rigid lithosphere overlies the weak asthenosphere (Tarbuck et al., 2014)

True

True or False. Rock cycle and water cycle can interact.

True

True or Fase. All of these processes have been operating throughout Earth's history, but the processes have become hazardous only because they negatively affect us as human beings.

True

True or false. Sediment deposition on top of these rocks produces layer 1 of the crust. Seafloor spreading carries these laterally away from the ridge axis in both directions (Hefferan & O'Brien, 2010)

True

Examples of Atmospheric/Hydrometeorologic Hazards

Typhoons, Tornadoes, Lightning and Thunderstorms, and Droughts

Age of Oceanic Crust

Up to 180 Ma for in-place crust ~3.5% of Earth history.

Age of Continental Crust

Up to 4000 Ma; 85-90% of Earth History

sheets of covalently bonded atoms held together by weak electrostatic forces. very weak bond

Van der Waals bonding

Is the degree or inability to resist to the effects/impacts of hazard or to respond when a disaster has occurred. It is a function of exposure/susceptibility, sensitivity, and adaptive capacity which may be viewed in various lenses related to the physical, economic, social, environmental, and/or institutional characteristics of an area.

Vulnerability

is a statement that a high probability of a hazardous event will occur, based on a prediction or forecast.

Warning

It is a mantle convection model which suggests that cold oceanic lithosphere sinks to great depths and stirs the entire mantle. the ultimate burial ground for subducting slabs is the core mantle boundary. This downward flow is balanced by buoyantly rising mantle plumes that transport hot material toward the surface.

Whole-Mantle Convection Model

proposed an ultra-low velocity zone (ULVZ) in the lowermost mantle on seismic evidence. These sporadic ULVZs may be related to the formation of deep mantle plumes within the lower mantle

Williams and Garnero (1996)

can atoms of the same element have different mass numbers?

YES, they are called isotopes

This layer is more plastic and flows slowly rather than rupturing when subjected to stress

asthenosphere

#protons + average #neutrons

atomic weight

have the same number of protons (i.e., same atomic number), can have different numbers of neutrons (referred to as isotopes), and can have different numbers of electrons.

atoms of the same element

consists principally of rocks such as:

basalt and gabbro

chlorine atom gains an electron

becomes negatively charged

sodium atom loses an electron

becomes positively charged

Molecules are held together by

chemical bonding

formation of a compound by combining two or more elements. manner in which electrons are distributed among atoms

chemical bonding

consists of elements that combine in a specific ratio.

chemical compound

is held in hydrous minerals and pore spaces.

connate water

true or false. seismic studies have shown that the outer core is seismically anisotropic

false. seismic studies have shown that the inner ore is seismically anisotropic

an atom that has gained or lost an electron

ion

Give four types of bonding

ionic, covalent, metallic, and Van der Waals

Why is continental crust termed "granitic" in composition?

it is enriched in enriched in K2O, Na2O and SiO2 relative to average crust.

Water cycle connects with the circulation of deep-seated _________ associated with magma production and the rock cycle

juvenile water

The formation of oceanic crust along the ridge axis generates layer 2, layer 3, and layer 4 which are the following:

layer 2 - pillow basalts and dikes layer 3 - gabbros of the oceanic crust layer 4 - mantle peridotites

thickness of crust in km

low density rock 7-70 km thich

occurs within the upper mantle at depths of ∼100 - 250km below the surface. The top of this zone marks the contact between the strong lithosphere and the weak asthenosphere.

low velocity zone (LVZ)

composition of oceanic crust

mafic rocks enriched in oxides of magnesium, iron and calcium (MgO, FeO and CaO) relative to average crust. composed largely of dark-colored rocks.

#protons + #neutrons is equal to

mass number

the substance of which any physical object is composed

matter

The hydrosphere - the surface and near-surface waters of the Earth - is made of

meteoric water.

can be developed to minimize this risk.

mitigation measures

The smallest quantity of a compound is called

molecule

Definition of a mineral

naturally occurring inorganic definite chemical composition ordered crystalline structure homogenous solid

layers of electrons that orbit around the nucleus

orbitals or energy-level shells

Where electronegativity differences in transitional ionic- covalent bonds are smaller than 1.68, the bonds are

primarily electron-sharing covalent bonds.

Where electronegativity differences are larger than 1.68, the bonds are

primarily electron-transfer ionic bonds.

defines the nucleus of an atom

proton + neutron

particles that make up an atom

protons, neutrons, and electrons

Under some oceanic islands, thickness of oceanic crust

reaches 18km

The great age of some continental crust results from its:

relative buoyancy

what constitutes the uppermost part of the mantle and crust?

relatively rigid lithosphere which is strong enough to rupture in response to stress.

lithopile, siderophile, chalcophile, and atmophile

silicate loving, iron loving, sulfur loving, and gas loving

is defined as one that emerges gradually over time. This could be associated with, e.g., drought, desertification, sea-level rise, and epidemic disease (Sendai Framework for DRR, 2015)

slow-onset disaster

states of matter

solid, liquid, gas

may be responsible for the anomalously fast velocities

subducted lithosphere that had sunk all the way to the D″ layer

it is triggered by a hazardous event that emerges quickly or unexpectedly. could be associated with, e.g., earthquakes, volcanic eruptions, flash floods, chemical explosions, critical infrastructure failure, and transport accidents (Sendai Framework for DRR, 2015).

sudden-onset disaster

disasters that are directly generated by humans, such as oil and toxic material spills, pollution, massive automobile or train wrecks, airplane crashes, and human-induced explosions.

technological disasters

controlling factors of matter

temperature and pressure

True or False. the oldest well-documented continental crust includes 5.1 Ga rocks from the Northwest Territories of Canada (Stern & Bleeker, 1998)

the oldest well-documented continental crust includes 4.03Ga rocks from the Northwest Territories of Canada (Stern & Bleeker, 1998)

True or false. In bonded atoms, electrons may be lost, gained, or shared

true

may be related to the formation of deep mantle plumes within the lower mantle.

ultra-low velocity zone (ULVZ)

is the circulation of meteoric water through the hydrosphere, atmosphere, and upper parts of the crust.

water cycle

inner core has density of

~13 g/cm3

The D″ discontinuity ranges from

∼130 to 340km above the core-mantle boundary