Module 1 Flashcards
The science of the earth.
Geology
Geology deals with different aspects of the
earth as a whole such as:
- origin, age, interior structure and history of the earth;
- evolution and modification of various surface features like
rivers, mountains and lakes along with their causes
(processes); and - the materials making up the earth.
The application of the geological sciences to engineering study for
the purpose of assuring that the geological factors regarding the
location, design, construction, operation, and maintenance of
engineering works are recognized and accounted for.
Engineering Geology
The philosophy of engineering geology is based on three simple
premises. These are:
- All engineering works are built in or on the ground;
- The ground will always, in some manner, react to the
construction of the engineering work; and - The reaction of the ground (its “engineering behavior”) to the
particular engineering work must be accommodated by that
work.
Main Branches of Geology
- Physical Geology – different physical features of the earth
- Mineralogy – study of minerals
- Petrology – study of rocks
- Structural Geology – formation and classification of geological
structures - Historical Geology – study of earth’s history through sedimentary
rocks - Paleontology – study of remnants of ancient life (fossils)
- Economic Geology – Economic mineral’s formation, properties etc.
Allied Branches of Geology
- Engineering Geology
- Mining Geology
- Geophysics
- Geohydrology
- Geochemistry
Structural Failures due to
Geological Causes
- 1928 St. Francis Dam Disaster
- Numerous landslides in the Philippines
____ is the largest of several
rocky planets in our Solar System
Earth
Earth is nearly spherical, measuring
_____ km from pole to pole and
______ km around the Equator,
and orbits the Sun at an average
distance of ____ million km.
12, 714 ; 12, 756 ; 150
The birth of the Sun grew by the
collapse of a slowly rotating
interstellar cloud of gas (mostly
hydrogen) and dust. This cloud is
referred to as the ______
solar nebula
The material that was not drawn
into the ______, where the
Sun was forming, became
concentrated in a _____ around the
Sun.
central point ; disc
Layers of the Earth
- Crust
- Mantle
- Core
It is the process that changes solid rock into
sediments. With _____, rock is disintegrated into smaller
pieces.
Weathering
It is the process that moves the sediments away from it’s
original position. The four forces of ____ are water, wind,
glaciers, and gravity.
Erosion
While plate tectonics
forces work to build huge
mountains and other
landscapes, the forces of
weathering and mass
wasting gradually wear
those rocks and
landscapes away, called ____
Denudation
It is also called physical weathering, breaks
rock into smaller pieces.
Mechanical Weathering
The rock has changed physically without changing its
______. The smaller pieces have the same minerals, in just
the same _______ as the original rock.
composition ; proportions
______ also called freeze-thaw weathering, is the main form of
mechanical weathering in any climate that regularly cycles above and below
the freezing point.
Ice wedging
It is another form of mechanical weathering. In ______, one rock
bumps against another rock.
Abrasion
It is different from mechanical weathering
because the rock changes, not just in size of pieces, but in
composition.
Chemical weathering
Chemical weathering works through ______ that cause changes in the
minerals.
chemical reactions
______ is the most important agent of chemical weathering.
Water
Two
other important agents of chemical weathering are _______ and ______
carbo dioxide ; oxygen
It is the name of the chemical reaction between a chemical
compound and water. When this reaction takes place, water
dissolves ions from the mineral and carries them away. These
elements have undergone leaching.
Hydrolysis
Carbon dioxide (CO2) combines with water as raindrops fall through
the atmosphere. This makes a weak acid, called _____
carbonic acid
______ is a very common in nature where it works to dissolve rock.
carbonic acid
Pollutants, such as sulfur and nitrogen, from fossil fuel burning, create
_____ and ____ acid
sulfuric ; nitric
_____ and ____ acids are the two main
components of _____, which accelerate chemical weathering.
sulfuric ; nitric ; acid rain
It is a chemical reaction that takes place when oxygen
reacts with another element.
oxidation
It is very strongly chemically
reactive.
Oxygen
The most familiar type of oxidation is when iron reacts
with oxygen to create _____.
rust
Minerals that are rich in iron break down as the iron oxidizes and
forms new compounds. ______ produces the red color in soils.
Iron oxide
Influences on Weathering
- Rock and Mineral Type
- Climate
It occurs when loose, water
saturated sediment begins to compact
causing the ground surface to collapse.
Subsidence
It occurs when the water
within the sediment is slowly squeezed
out because of overlying weight
Slow subsidence
It occurs when
naturally acidic water begins to
dissolve limestone rock to form
a network of water-filled
underground caverns
Fast subsidence
But if ______ or ______ reduces the water
table below the level of the
caves, this caverns collapse
creating surface sinkholes.
droughts ; pumping of
ground water
From the physical geology
standpoint, an _______ happens
when two blocks of the earth
suddenly slip past one another. The
surface where they slip is called
________.
earthquake ; fault or fault plane
The energy radiates outward from
the fault in all directions in the
form of _______ like ripples
on a pond.
seismic waves
The study of earthquakes and the waves they
create
Seismology
A scientist who study and measure earthquakes
to learn more about them and to use them for geological
discovery
Seismologist
Recordings of the ground shaking at the specific
location of the seismograph
Seismograms
Recording instruments used to record the
motion of the ground during an earthquake
Seismographs
The internal part of the seismograph, which may
be a pendulum or a mass mounted on a spring; however, it is
often used synonymously with seismograph
Seismometer
The place of origin of the
earthquake in the interior of the earth
Focus, Origin, Center, or Hypocenter
The place on the earth’s surface, which lies directly
above the center of the earthquake
Epicenter
The point on the earth’s surface diametrically
opposite to the epicenter
Anticenter
The imaginary line which joins the center and
the epicenter. This represents the minimum distance which the
earthquake has to travel to reach the surface of the earth
Seismic Vertical
An imaginary line joining the points of same
intensity of the earthquake
Isoseismal
An imaginary line which joins the points at which
the earthquake waves have arrived at the earth’s surface at the
same time
Coseismal
The form of the transmitted energy released
from the focus at the time of the earthquake
Seismic Waves
Proportional to the energy released by an
earthquake at the focus. It is calculated from earthquakes
recorded by a seismograph.
Magnitude
The strength of an earthquake as perceived and felt
by people in a certain locality.
Intensity
Classification of Earthquakes
- Based on depth of focus
- Based on the cause of occurrence
Earthquakes with a focus depth of less than 50 km
Shallow Earthquakes
Earthquakes with a focus depth of more than 50 km but less than 250
km
Intermediate Earthquakes
Earthquakes with a focus depth of more than 250 km
Deep Earthquakes
Are exclusively due to internal causes, i.e., due to
disturbances or adjustments of geological formations taking place in
the earth’s interior.
Tectonic Earthquakes
Type of earthquakes that are generally due to
external or surficial causes.
Non-tectonic Earthquake
Over time stresses in the Earth build up (often caused by the
slow movements of tectonic plates). At some point the stresses
become so great that the Earth breaks… An earthquake rupture
occurs and relieves some of the stresses (but generally not all).
Elastic Rebound Theory
The outer crust of the Earth is divided into rigid plates that are
called _______. The edges of these plates are known as
_______.
tectonic plates ; plate boundaries
Types of Fault
- Normal fault
- Reverse fault
- Strike-slip fault
The rupturing process creates _____ in the Earth that
propagate away from the rupture front at a much faster speed
than the rupture propagates, the exact speed depends upon the
nature of the wave and on the elastic properties of the Earth
elastic waves
The primary body wave; the first seismic wave detected by
seismographs; able to move through both liquid and solid rock
P-wave
Secondary body waves that oscillate the ground
perpendicular to the direction of wave travel. They travel about 1.7
times slower than P waves.
S-wave
Because liquids will not sustain shear
stresses, S waves will not travel through liquids like ______, ______, or the ________.
water ; molten
rock ; the Earth’s outer core
S waves produce _______
motion in the ground surface.
vertical and horizontal
Surface waves that move in an elliptical motion,
producing both a vertical and horizontal component of motion in the
direction of wave propagation.
Rayleigh wave
Surface waves that move parallel to the Earth’s surface
and perpendicular to the direction of wave propagation.
Love wave
PHIVOLCS means ____
Philippine Institute of
Volcanology and Seismology
Effects of Earthquakes on Structures
- Ground Conditions
- Building Design and Construction
- Materials
- Resonance Frequency
Gives us the earthquake
provisions to design seismic-resistant
structures to safeguard against major
structural damage that may lead to loss of
life and property.
National Structural Code of the
Philippines (NSCP) 2015 in Section 208:
Earthquake Loads
