Anna university syllabus

1. Engineering Geology
Unit – I
Physical Geology
Dr.N.Ilavarasan
Asstprof
Department of CivilEngineering
UCE– BITCampus Trichy

2. Definition:
• The sciences that deal with one or more
aspects of the Earth as a planet are grouped
together as Earth science.
• Geo - Earth ; Loges – science
• Earth science Geology
• • It is the science that deals with the study of
Earth as a whole.

3. Engineering Geology
• EG may be defined as that branch of applied
sciences which deals with the application of
geology for a
– Safe
– Stable
– economical design & construction of civil
engineering projects

4. Why Geology
• Geology plays a very important role in the
field of civil engineering.
– It provides knowledge about materials used for
construction.
– Its knowledge is helpful for constructing dams.
– Geotechnical engineers needs knowledge about
this subject for excavation work (digging work).

5. Scope of Geology in Civil Engineering
• The basic two objects are
– It enables a civil engineer to understand Engg.
Implications of certain conditions related to the
area of construction, which are essentially
geological in nature.

6. Scope of Geology in Civil Engineering
• It enables a geologist to understand the Nature
of geological information which is absolutely
essential for a safe design & construction of a
civil engineering projects.

7. The major activities of a civil
engineering are in
•Construction job
•Water Resource
Development
•Town & Regional Planning

8. Geology in construction jobs
• Construction jobs like
– Dams & reservoirs
– Tower
– Tanks
– Highways & bridges
– Traffic & hydro power tunnels
– Embankments & retaining structures
– Lining of canals
– Laying of drainage pipes etc
• We need to have a clear idea about the site,
Planning, Design, Construction.

9. Planning
• Topographic Maps
– Relief features - essential to understand the merits
& demerits
– The nature of slopes, depth of valley,
– Rate of change to elevation in various directions
can be easily computed.
• Hydrological maps
– Surface & subsurface water channel, its
occurrence & depth.

10. Planning
• Geological Maps
– Rock types
– Structural disposition of rocks
– Materials of construction
– Exploratory operations (test holes etc.)
– Subsurface investigation

11. Design
• The existence of hard bedrocks & their depth
from & inclination with the surface.
• The Mechanical properties of the rock
especially compressive, shear & transverse
strength, modulus of elasticity, permeability &
resistance to decay.

12. Construction
• To check the quality control of the construction
materials like sands, gravels, gushed rocks & soil.

13. Geology in water Resources
Development
• • Water cycle is the term given to the sum
total of water cycle:
– evaporation of water from the hydrosphere + its
precipitation in the form of rain & snow + flow
back into the lakes, sea & oceans
• . • It depends on Surface & subsurface water.

14. Hydrological cycle

15. Geology in Town & Regional planning
• A town planner is concerned with landscape &
its utilization
– i.e. maximum benefits with minimum of
disturbance to Natural environment.
• A regional planner is responsible for adopting
an integrated approach in all such cases of
allocation of land for development projects

16. • Geological mapping
• Exploration
• Project planning
• Hydrological / surface water maps
• Hydrogeological maps
• Slope stability/landslide/landslip
• Hydraulic structure / Dams and Reservoirs
• Seismic hazard/seismicity
• Environmental Impact Assessment

17. Geology in civil engineering

18. Branches of geology
Main and Branch of Geology
• Physical Geology
• Mineralogy
• Petrology
• Structural Geology
• Historical Geology
• Palaeontology
• Economic Geology
Allied Branch of Geology
• Engineering Geology
• Mining Geology
• Geophysics
• Geohydrology
• Geochemistry

19. Physical Geology
• This is also called as Dynamic geology or
Geomorphology.
– Physical Geology deals with the different Physical
feature of the earth such as Mountain, rivers,
lakes, glaciers and volcanoes.
– It also deals with different changes occurs on
earth surface like marine, formation or
disappearance of rivers, spring and lakes.

20. Physical Geology
• Natural phenomena like land slides, earth
quake and weathering.
• Geological works of wind glaciers river oceans
ground water and their role in constantly
moulding of earth surface

21. Physical Geology

22. Physical Geology
• The structural disposition of the rock bodies &
huge bodies of water & ice form other specific
subjects of study is physical Geology. It deals
with internal agents (volcanism & earthquake)
External agents (wind, water, ice &
atmosphere)

23. Mineralogy
• This deals with the study of minerals.
Mineralogy deals with the detailed mode of
formation, composition, occurrence, types,
association, properties and uses etc .

24. Civil Engineering point of view
• The strength and durability of the material
depends on chemical composition. The
quartzite and marble resemble one another in
shine colour and appearance but quartzite by
virtue of its mineral composition is very hard
tough, strong and durable while the marble
disintegrates and decomposition in a short
period because of its mineral composition and
properties

25. Petrology
• Petro =Rock, Logos =Study.
• Petrology deals with study of Rocks .
– The earth crust is also called as lithosphere, is
made of different types of rocks. Petrology deals
with the formation, structure, texture,
composition, occurrence, types etc.

26. Rocks types
Igneous rock Metamorphic rock
Sedimentary rock

27. Civil Engineering point of view
• The composition and texture characteristics of
rocks primarily contribute to their strength
and durability. Rocks based on their suitability
can be used for foundation for dams,
tunnelling's and other construction materials.
Hence it is most important branch of Geology
from civil Engineering point of view.

28. Structural Geology
• The rocks which forms the earth’s crust
undergoes various deformation, dislocations
and disturbances under the influence of
tectonic plates forces.
• The results is the occurrence of geological
structures like folds, faults, Joints and
unconformities in the rocks.
• The detailed mode of formation, causes,
types, classification, important etc.,

29. Structural Geology

30. Civil Engineering point of view
• Geological structures modified the inherent
physical characteristics of rock rendering them
more suitable or unsuitable for civil
engineering purpose.
• Dam site sedimentary rocks with upstream
dip provided a desirable geological setup
while the same rock with down stream dip
make geological setup un desirable.

31. Historical Geology
• The earth surface was always suitable condition for the
deposition of sediments at some place or other place.
• Therefore there are sedimentary rocks on the earth
representing the entire period of the earth history.
• proper investigation of this rocks reveals the
chronological sequence of formation of rocks,
evolution ,migration and plants and animals life
during different period of the earth history.
• These kind of study of the earths history through
sedimentary rocks is called historical geology.

32. Historical Geology

33. Paleontology
• If , under favorable condition, animals and
plants life gets embedded in sediments , it
will be preserved partly or completely .such
remnants of ancient life preserved in rocks by
natural processes are known as Fossils. Details
of mode of formation of fossil their types,
occurrence etc form the subject matter of
palaeontology. Its not much important from
civil engineering point of view.

34. Paleontology

35. Economic Geology
• The prosperity of a nation depends to a large
extent of rich reserves of economical minerals
deposit. Gulf countries are rich because of
their oil deposit; South Africa is rich because
of its gold and diamond deposited. It deals
with the mode of formation, occurrence,
classification, association, varieties and
concentration, properties and uses. etc Its is
related to economic importance.it is not
related civil engineering point t of view

36. Engineering Geology
• This deals with the application of geological
knowledge in the field of civil engineering for
execution of safe, stable and economic
construction like dams, bridges and tunnels.

37. Engineering Geology

38. Mining Geology
• This deals with the application of geological
knowledge in the field of mining. A mining
engineer is interested in the mode of extent of
occurrence of ores, their association, tenor,
properties etc.,
• It is also necessary to know other physical
parameter like depth, direction (strike),
inclination (dip) thickness and ore bodies.

39. Mining Geology

40. Geophysics
• The study of physical properties like density and
magnetism of earth.
• It is sub divided into Pure geophysics and
Exploration geophysics.
• Pure geophysics deals with general aspects of
earth as a whole and Exploration geophysics
deals with the study of upper layer of the earths
crust in order to solve civil engineering problem
and locating oil, gas and ground water explore
and estimate the ore deposit.

41. Pure Geophysics

42. Exploration geophysics

43. Geo hydrology
• This may also called as Hydrogeology. It deals
with occurrence, movement and nature i.e.,
(quality and quantity) of ground water in an
area. This branch is closely related to geology
because the very existence movement of
ground water are directly related to porosity ,
permeability, structure, texture and
composition of ground water and under
ground rocks

44. Geohydrology

45. Geochemistry
• This branch is relatively more recent and deals
with occurrence , distribution, abundance,
mobility, etc., of different elements on the
earth crust. It is not important from the civil
engineering point of view

49. Structures of earth and its composition

50. Structures of earth and its composition

59. Weathering of rocks

94. Scale of weathering

95. soil

96. Landforms and its processes
associated with river

98. The Work of Rivers
• The erosional work of streams/rivers carves
and shapes the landscape through which they
flow.
• Three functions of rivers
a. Erosion
b. Transportation
c. Deposition

100. The Work of Rivers
A.Erosion
• A river may erode in 4 ways
1.Abrasion/corrasion
– Load carried by a river will grind against its bed
and sides.
– This process slowly wears the bed and sides away.

101. The Work of Rivers
A. Erosion
2. Attrition
– When thrown against the sides and bed of rivers,
the load gets broken into smaller pieces.

102. Complete River System

103. The Work of Rivers
A. Erosion
3. Hydraulic action
– The work of turbulence in the water.
– Running water causes friction in the joints of rocks
in a stream channel
– Joints may be enlarged
– Loosened fragments of rocks get swept away.

104. The Work of Rivers
A. Erosion
4. Solution/Corrosion
– Certain minerals in rocks like limestone can be
dissolved in water.
– Rocks are then eroded.

105. The Work of Rivers
• Relationship of velocity and sediment size to
erosion

107. The Work of Rivers
• B. Transportation (4 ways)

108. The Work of Rivers
• B. Transportation (4 ways)
1.Traction
– Larger and heavier rocks/gravels are dragged or rolled
along the bed.
2. Saltation (saltim: by leaps/jumps)
– Smaller and lighter rock fragments and sand hop and
bounce along the river bed.
– At times, the distinction between traction and
saltation may be difficult to determine.

109. The Work of Rivers
B. Transportation (4 ways)
3. Suspension
– Some of the load like silt and clay (fine-grained)
will float along.
– They may only be deposited when stream velocity
reaches near 0.
– Turbulence in the water is crucial in holding a load
of sediments.

110. The Work of Rivers
• B. Transportation (4 ways)
4. Solution
– Some minerals are transported in dissolved form.
– Especially chemical solution derived from minerals
like limestone or dolomite.

111. The Work of Rivers
• C. Deposition
• A river will drop its load when:
a. Volume decreases
b. Speed decreases

112. The Work of Rivers
• C. Deposition
• A river’s volume decreases when
• Dry season
• Dry region with high evaporation
• Presence of permeable rocks
• Receding flood waters

113. The Work of Rivers
• C. Deposition
• A river’s speed decreases when
• It enters a lake
• It enters a calm sea
• It enters a gently sloping plain

114. The Work of Rivers
• The work of a river depends on its energy
• Energy a function of
a. Volume of water
b. Speed of water flow (dependent on gradient)

115. Features of river work
• Vertical erosion
• Rapids
• Waterfalls & Gorges
• Meanders & Oxbows
• Floodplains & Levèes
• Deltas

116. Vertical erosion
• Vertical erosion can be
great in some areas and
create gorges, canyons,
potholes .
• Potholes-smooth
rounded hollows
formed by stones
trapped in the hollows
of a river bed

117. Rapids
• Form where the water
is shallow and the river
bed is rocky & irregular
making the water rough
• Usually in steeper areas
• Can make river travel
difficult unless white
water rafting/kayaking

118. Waterfalls & Gorges
• Valley sides are steep and form a ‘V’ shaped
cross section is called Gorges

119. Waterfall formation
Hard Rock – Lava
Soft Rock – Sandstone or Conglomerates
Soft rock is easy to
erode, but the hard rock
is resistant.
So over time a ledge
develops.

120. Waterfall formation
The water rushes over the
ledge and erodes a plunge
pool by abrasion and
hydraulic action.

121. Waterfall formation
The ledge collapses into
the plunge pool, where
the debris helps to
speed up the erosion.

122. Waterfall formation
The process is repeated
and the waterfall
gradually retreats
upstream, carving out a
gorge.

123. Floodplains & Levèes
• Flat land next to a river
liable to flood
• Occasionally the river
flows above the level of
the surrounding plain
but is enclosed by
raised embankments
called levèes

125. Floodplains & Levèes

126. Deltas
• Low-lying flat marshy
land where a river
meets a sea/lake
• Formed from a river
with carrying a lot of
sediments that meets a
still sea/lake and the
sediments build up
• May cause
distributaries

128. Meanders & Oxbows
Meanders
• Meanders develop and
migrate laterally and
downstream
• Helicoidal flow further
assists meander formation
and transports sediment
from river cliff to the slip-off
slope on the inside of the
next bend.
Oxbows
• Downstream migration of
meanders produce
pronounced meander loops
whichmay form ox-bow lakes
during flood conditions

129. Meanders

130. Meanders

131. Oxbows lakes

133. Meanders & Oxbow Lakes

134. Landforms and its processes
associated with wind

135. The Work of Wind
• It refers specifically to the wind’s ability to
shape the surface of the earth.
• Winds may erode, transport and deposit
materials.
• Aeolian processes are important in arid and
semi arid environments such as deserts.

136. WIND ACTION CAN BE DIVIDED INTO
THREE PARTS
• Erosion
• Transportation
• Deposition

137. Types of erosion
1. Abrasion or corrasion:
The wearing down of surfaces by the grinding action
and sand blasting of windborne particles.
2. Deflation:
The lifting and removal of loose, fine grained
material from the earth surface. Forms shallow
basins called deflation basins.
3. Attrition:
Attrition is the grinding action , while on transit wind
borne particles often collide with one another. Such
mutual collision brings about a further grinding of
the particles

138. EROSIONAL LANDFORMS
a) Ventifacts:
• Formed by abrasion
effect.
• Exhibit one or more
polished and faceted
surfaces.
• They are relatively rare.

139. EROSIONAL LANDFORMS
b) Yardang:
• Ridges that are sculpted
And streamlined by
wind abrasion and
deflation.
• Elongated in the
direction of prevailing
wind and are nearly
always carved from
relatively weak
materials.

140. EROSIONAL LANDFORMS
c) Mushroom table or
pedestal rock:
• A rock having broad
upper and narrow base
resembling an
mushroom shape is
called mushroom rocks,
formed due to abrasive
work of wind.

141. EROSIONAL LANDFORMS
d) Desert pavements or lag
deposits:
• The left behind closely
packed, interlocking,
angular or rounded rock
fragments of pebble and
cobble by wind deflation
are known as lag deposits.
• A desert pavement is also
called “reg” in western
Sahara,“Serir” in Eastern
Sahara, “Gibber” in
Australia and “Sai” in
Central Asia.

142. EROSIONAL LANDFORMS
e) Blowouts:
• Sandy depressions in a
sand dune ecosystem
caused by the removal
of sediments by wind.
• Blowouts develop in
areas where
nonindurated materials
lie beneath the land
surface.

143. TRANSPORTATION BY WIND
• Three methods:
• Saltation:
– Transported through a series of bounces.
• Suspension:
– particles are lifted high into atmosphere and are
carried great distances before they settle.
• Rolling or Traction:
– the movement of particles on ground. The coarser
fragments are carried in this way.

144. TRANSPORTATION BY WIND

145. DEPOSITIONAL LANDFORMS
a) Wind or sand ripples:
• Miniature dunes within
a dune (not more than
2 inches tall).
• May form from cross
winds and appear to be
traveling in a different
direction than the large
dune.

146. DEPOSITIONAL LANDFORMS
b) Loess:
• An aeolian sediment formed
by the accumulation of wind
blown silt typically in the 20-
50micrometer size range.
• Buff-coloured, non-indurated,
calcareous and permeable.
• They occur at variable
altitudes and are readily
recognized as Aeolian
deposits.
• Loess is the raw material for
many mollisols, the best
agricultural soils.

147. DEPOSITIONAL LANDFORMS
c) Sand dunes:
• Piles of sand deposited
by wind.
• Leeward side (slipface)
has a steeper slope.
• Windward side is more
gradual.

148. Suspended Load Transport and
Deposition
• In dry areas very high winds can suspend fine
sand particles

151. Landforms and its processes
associated with sea

152. Working of sea
Waves
• Ordinary Waves are caused by WIND
– Waves are produced when wind drag causes
the surface water of oceans/lakes to rise
and fall
- Waves get refracted on approaching
shoreline

153. Parts of A Wave

154. Oscillatory and Translatory waves

155. Working of sea
• Erosion
• Transportation
• Deposition

156. Erosion
• Hydraulic Action; direct force of the waves on the coast.
• Abrasion; rock debris is hurled by the waves against the
coastline.
• Attrition; fragments of stone are rounded and eroded by
hitting off each other.
• Solution; minerals in certain rocks are dissolved by water.
• Air Compression; breaking of rock as a result of being
trapped by waves in rocks.
• Wave Refraction; bending of waves concentrates erosion at
headlands, this then leads to the formation of cliffs, caves,
arches and stacks.

157. Processes of coastal erosion
– Hydraulic Action
– Compression
– Abrasion/Corrasion
– Attrition
– Solution/Corrosion

158. Landforms of Marine Erosion
• Cliffs
• Wave-cut
Platform
• Bay
• Headland
• Cave
• Blowholes
• Sea Arches
• Sea Stacks

159. Cliffs
Cliffs are vertical slopes on a coastline Form
as a result of a combination of coastal
processes of erosion, such as hydraulic
action, compression, abrasion, solution and
attrition.
Destructive waves attack an area of
weakness in rocks Crack/joint forms
Crack/joints are attacked by hydraulic force of
the water and by compression Notch forms

160. Wave-cut Platform
Wave-cut platforms
– surface of rock that
remains in front of the
retreating cliff
Wave-built terraces
– deposited pieces of
rock that are deposited
below low-tide level

161. Bays and Headlands
Differential erosion – rocks along
coastlines are eroded at differing rates
depending on whether they are soft
or hard
Sections of coastline that are
composed of soft rock will erode
faster than areas composed of hard,
more resistant rock
Stretches that are composed of soft
rock will form bays
Harder more resistant rock will take
longer to erode and will remain jutting
out into the sea as headlands

162. Bays and Headlands

163. Bays and Headlands

164. Sea Caves, Sea Arches, Sea Stacks and
Sea Stumps
 Caves form in an area of weakness on a cliff face or
headland
 Processes of coastal erosion act on this area of weakness
and enlarge it to form caves
 Caves are further eroded by abrasion, resulting in them
becoming larger
 Sea arches form when continued erosion occurs in a sea
cave causing it to extend right through the headland
 A sea arch may also form when two sea caves form back to
back on the opposite sides of a headland

166. Deposition
Coastal Landforms

167. Deposition
• Coastal deposition occurs when waves lose
energy and therefore their ability to carry
material
• Sea deposits its load on the coastal area
• Constructive waves have an ability to move the
load inland
• Wave refraction in bays result in wave energy
decreasing and this results in deposition
occurring
• Deposited material may include shingle, sand and
sediment

168. Landforms of Marine Deposition
• Beach
• Storm Beach
• Sand Spit
• Sand Bar
• Lagoon
• Tombolo

169. Beach
– A beach is an area of sand, shingle or gravel
– Beaches are created by the processes of longshore
drift, constructive waves and wave refraction,
– Located in an area between low tide mark and
where the highest storm waves can reach
– Constructive waves swash is powerful
– Waves move up the sea shore, slow down and
their load of sand and rocks is deposited
– Heavier load of rock and shingle is deposited on
the backshore
– Finer, lighter material such as sand is deposited on
the foreshore
– Over time a beach is formed

171. storm beach
 A storm beach is made of pebbles and stones
 It forms when waves are strong enough to push large rocks
and boulders above the high tide mark
 A storm beach is usually steeper than a regular beach.

172. Sand Dunes
– Hills of sand
– Sand is dried and blown inland
– Vegetation can trap the sand
– Marram grass is sometimes planted to prevent it
blowing further inland
– Eg; Curracloe, Co Wexford

173. Berms
– Ridges, like steps or terraces
– Gentle constructive waves push sediment into long low
ridges
– Mark the junction between foreshore and backshore

174. Runnels & Ridges
– Runnels-depressions on the sand on the foreshore
– Ridges-the gentle rises between the runnels
– Formed by the action of constructive waves

175. Cusps
– Cresent shaped hollows where shingle changes to
sand
– Result of complex wave actions on pebble beaches

178. Sand Spit
 A sand spit is a long narrow ridge of deposited sand
and shingle
 It is connected to the coast at one end
 Sand spits develop due to longshore drift and
deposition
 Sand spits form where the process of longshore drift is
interrupted
 Waves lose energy and slow down
 Location of estuary or change in wind direction
 Sediment is deposited in sheltered and shallow water
 Over time this sediment builds up and becomes visible
above the level of the sea

181. Sand Bar & Lagoon
A sand bar forms when a sand spit extends across a
bay
Sand bars will eventually seal off an area of coastline
The water directly behind the sand bar will then be
called a lagoon

183. Two Types of Sand Bar
Offshore Bar
 Located away from the
coastline
 Parallel to the coastline
 Generally only exposed at
times of low tide
 Breaking waves deposit sand
on the offshore bar
 Size of the offshore bar
increases over time
 May eventually block or close
off the bay creating a lagoon
Baymouth bar
 Sand spit extends from one
side of a landmass
across a bay and reaches the
other landmass
 Blocks/closes off the bay
 Example
 Our Lady’s Island, Co.
Wexford.

185. Tombolo
 Tombolos are formed due to wave refraction and
longshore drift
 Result from a sand spit extending out to an island
and connecting the island to the mainland
 Waves approach the island, wave refraction occurs
 Sediment is deposited
 Results in the spit connecting the island to the
mainland and – a tombolo is formed

186. Tombolo

187. CORAL REEFS
• Peculiar types of ridge-like marine deposits
which have been formed due to accumulation
of dead parts of certain types of sea-
organisms - corals (calcium secreting
organisms

188. CORAL REEFS

189. Landforms and its processes
associated with groundwater

190. Process of groundwater
• The chemical process of groundwater is
known as KARST
• Karst landscapes are predominantly composed
of limestone rock that contains > 70 percent
calcium carbonate.

191. Additional Consideration: Water Table
• Rocks are dissolved by water: surface water or
groundwater.
– Carbonates, limestone (CaCO3 ), and dolostone
(CaMg(CO3 )2 )are dissolved by acidic water.
– Evaporites, rock salt, and gypsum (CaSO4 .2H2O)
are dissolved by water.

194. Chemical Weathering: Carbonation
• Carbonation is a process by which carbon
dioxide and water chemically react to produce
carbonic acid, a weak acid, that reacts with
carbonate minerals in the rock.
• This process simultaneously weakens the rock
and removes the chemically weathered
materials.

195. Chemical Weathering: Carbonation

196. Chemical Weathering: Carbonation
• Carbonation primarily occurs in wet, moist
climates and effects rocks both on and
beneath the surface.
• Carbonation occurs with limestone or
dolomite rocks and usually produces very fine,
clayey particles.

197. Chemical Weathering: Carbonation

198. Factors affecting Karst Processes
• Solubility of Bedrock
– percent calcite
• Climate
– Temperature and Moisture
• Structure of Limestone
– joints, fractures, porosity
• Vegetation/Non-carbonate Geology
– acidity (pH) of groundwater
• Atmospheric CO2
– affects solubility of Carbonates

199. Surface Landforms: Limestone
Pavement

200. Features of limestone pavements
• Clint: section of a limestone pavement
separated from adjacent sections by grikes
• Grike: vertical crack that develops along a joint
in limestone.
• Karren: small hollow that forms on the surface
of a limestone clint

201. Features of limestone pavements

202. Surface Landforms: Sinkholes
• Collapsed/depressed limestone features that
develop in karst landscapes.
• The ground water slowly dissolves the
limestone rock below the surface until it
eventually becomes unstable and collapses
creating local depressional features.

203. Surface Landforms: Sinkholes

204. Sinkholes
• Groundwater
dissolves soluble rock,
creating fractures and
caves.
• Dissolving continues
to form larger caves
and fractures.

205. Dolines (Sinkholes, Cenotes )
• Collapse sinkholes form
when water level drops
• Solution sinkholes due
dissolution at surface

206. Sinkholes
• Often occur along the
same subterranean
drainage system
• Uvala: series of
smaller sinkholes
coalesce into a
compound sinkhole

207. Surface Water Features
• Karst regions are noted for their lack of well-
established surface drainage.
• Surface drainage is actually replaced by
extensive underground drainage.
• Where surface streams do develop, they do
not flow very far – they “disappear”
(disappearing streams) and “reappear”
(springs).

208. Surface Water Features

209. Disappearing Streams
• Streams that flow on the surface and then
seemingly “disappear” below ground.
• Disappearing streams disappear into a
sinkhole or other karst solution features
(caves).
• They may also disappear into factures or faults
in the bedrock near the stream.
• Disappearing streams are also referred to as
losing streams, sinks, or sieves.

210. Disappearing Streams

211. Sinking stream in karst area of
Kentucky

212. Springs
• Karst springs are locations where groundwater
emerges from the limestone and flows across the
surface forming a stream or contained pool.
• The flow of Karst springs is generally dependant
on the weather and climate.
• Ephemeral springs only flow following rainfall or
snowmelt events.
• More permanent springs are connected to
aquifers and flow year-round

213. Springs

214. Cockpit Karst
• Cockpit karst is a form of karst in which the
residual hills are chiefly hemispheroidal and
surround closed, lobed, depressions known as
dolines or "cockpits" each of which is drained
to the aquifer by one or more sinkholes

215. Cockpit Karst region in Jamaica

216. Karst Towers
• Landscape is mottled with a maze of steep,
isolated limestone hills.
• Limestone beds are thick and highly jointed
• Puerto Rico, western Cuba, southern China,
and northern Vietnam.
• CO2 production by vegetation in these
climates facilitates weathering.

217. Karst Towers

218. Subsurface Karst Features: Caverns
• Limestone caverns and caves are large sub-
surface voids where the rocs has been
dissolved by carbonation.
• In sections where the ground water table has
dropped, pressure release promotes
precipitation of minerals creating a variety of
speleothems

219. Subsurface Karst Features: Caverns

220. Subsurface Karst Features: Caverns
• Calcium carbonate precipitates out of the saturated
carbonate solution and accumulates as deposits.
• Stalactites are deposits that grow from the ceiling
downward
• Stalagmites are deposits that grow from the ground up.
• If the stalactite and stalagmites join they form a
continuous column.
• Mammoth Cave in Kentucky and Carlsbad Caverns in
New Mexico are two of the largest cave systems in
North America .

221. Karst: Caves & Caverns

223. Soda straws to stalactites
• Soda straws are initially hollow, allowing
dissolved limestone to travel through the
tube.
• Because a dissolved solid is traveling through
the tube, it sometimes gets plugged up.
• This forces the dissolved limestone to “back
up” and start flowing on the outside of the
straw.
• Eventually, it thickens and becomes
recognizable as a stalactite!

225. Cycle of Erosion in a Karst Topography
• Three stages:
– Youthful
– Mature
– Old age

226. Additional Fun Karst Features
• Abîme, a vertical shaft in karst that may be very
deep and usually opens into a network of
subterranean passages
• Cenote, a deep sinkhole, characteristic of Mexico,
resulting from collapse of limestone bedrock that
exposes groundwater underneath
• Foibe, an inverted funnel-shaped sinkhole
• Scowle, porous irregular karstic landscape in a
region of England

227. Additional Fun Karst Features
• Turlough (turlach), a type of disappearing lake
characteristic of Irish karst
• Uvala, a collection of multiple smaller individual
sinkholes that coalesce into a compound
sinkhole. Word derives from South Slavic
languages.
• Karren, bands of bare limestone forming a
surface
• Limestone pavement, a landform consisting of a
flat, incised surface of exposed limestone that
resembles an artificial pavement

228. Additional Fun Karst Features
• Polje (karst polje, karst field), a large flat specifically
karstic plain. The name "polje" derives from South
Slavic languages.
• Doline, also sink or sinkhole, is a closed depression
draining underground in karst areas. The name
"doline" comes from dolina, meaning "valley", and
derives from South Slavic languages.
• Karst spring, a spring emerging from karst, originating
a flow of water on the surface
• Ponor, also sink or sinkhole, where surface flow enters
an underground system. Derived from South Slavic
languages

229. Plate tectonics

256. Earth quakes

257. DEFINITION:
• A sudden violent shaking of the ground,
typically causing great destruction, as a result
of movements within the earth's crust or
volcanic action.
• A sudden release of energy in the earth's
crust or upper mantle, usually caused by
movement along a fault plane or by volcanic
activity and resulting in the generation of
seismic waves which can be destructive.

258. Sesimic Waves
• Seismic waves are waves of energy that travel
through the Earth's layers, and are a result of
an earthquake, explosion, or a volcano that
gives out low-frequency acoustic energy.
• Seismic waves are studied by geophysicists
called seismologists.
• Seismic wave fields are recorded by a
seismometer, hydrophone (in water), or
accelerometer.ncy acoustic energy.

259. Sesimic Waves
• The propagation velocity of the waves
depends on density and elasticity of the
medium.
• Velocity tends to increase with depth and
ranges from approximately 2 to 8 km/s in the
Earth's crust, up to 13 km/s in the deep
mantle.

260. Classification and causes of
Earthquake
• Based on depth of their origin, earthquake are
described as shallow or intermediate or Deep.
• Earthquake with a focus depth less than 60km
are called shallow earthquake.
• If the depth more than 60km but less than
300km, they are called Intermediate
earthquake.
• Which have focus depth more than 300km,
they are called Deep earthquake.

261. • Based on the causes responsible for their
occurrence, earthquakes are described as Tectonic
or non Tectonic.
• Tectonic earthquake are exclusively due to internal
causes, due to disturbances or adjustments of
geological formations taking place in the earth’s
interior, they are les frequent, but more intensive
and hence more destructive in nature.
• The Non Tectonic earthquake on the other hand,
are generally due to external or surfacial causes.
This type of earthquake is very frequent, but minor
in intensity and generaly not destructive in nature.

262. Types
• Among the many types of seismic waves, one
can make a broad distinction between body
waves and surface waves.
• Body waves travel through the interior of the
Earth.
• Surface waves travel across the surface.
• Surface waves decay more slowly with
distance than do body waves, which travel in
three dimensions.

263. Includes Primary and Secondary
waves:
• Primary waves(P-wave):
• Primary waves are compression waves that are
longitudinal in nature.
• P waves are pressure waves that travel faster
than other waves through the earth to arrive at
seismograph stations first, hence the name
"Primary".
• These waves can travel through any type of
material, including fluids, and can travel at nearly
twice the speed of S waves.

264. Primary waves(P-wave
• In air, they take the form of sound waves,
hence they travel at the speed of sound.
• Typical speeds are 330 m/s in air, 1450 m/s in
water and about 5000 m/s in granite.

265. Secondary waves(S-Waves)
• Secondary waves (S-waves) are shear waves that
are transverse in nature.
• Following an earthquake event, S-waves arrive at
seismograph stations after the faster-moving P-
waves.
• S-waves can travel only through solids, as fluids
(liquids and gases) do not support shear stresses.
• S-waves are slower than P-waves, and speeds are
typically around 60% of that of P-waves in any
given material.

266. Definition
• An Earthquake is a sudden and rapid shaking of the ground
due to passage of vibrations beneath caused by transient
disturbance of elastic or gravitational equilibrium of rocks.
• The scientific study of earthquakes is called Seismology.
• Earthquakes are measured using observations from
seismometers.
• Seismic waves are recorded on instruments called
seismographs.
• The time, locations, and magnitude of an earthquake can
be determined from the data recorded by seismograph
stations.

267. RICHTER MAGNITUDE SCALE
• The Richter magnitude scale was developed in 1935 by
Charles F. Richter.
• Earthquakes with magnitude of about 2.0 or less are
usually called micro earthquakes; are generally
recorded only on local seismographs.
• Events with magnitudes of about 4.5 or greater, are
strong enough to be recorded by sensitive
seismographs all over the world.
• Great earthquakes have magnitudes of 8.0 or higher.
• On the average, one earthquake of such size occurs
somewhere in the world each year.

269. Man-made Earthquakes
• The impounding of large quantities of water
behind dams disturbs the crustal balance.
• The shock waves through rocks set up by the
underground testing of Atom bombs or
Hydrogen bombs may be severe to cause
earthquake.

270. CAUSES
• Natural Causes of Earthquake:
– Tectonic Movement
– Volcanic Activity
– Pressure of gases in the interior
– Landslides and avalanches
– Faulting and folding in the rock beds are
responsible for causing minor earthquakes.

271. Man-made Earthquakes
• The impounding of large quantities of water
behind dams disturbs the crustal balance.
• The shock waves through rocks set up by the
underground testing of Atom bombs or
Hydrogen bombs may be severe to cause
earthquake.

272. EFFECTS
• Destructive Effects:
– Earthquake causes dismantling of buildings, bridge
and other structures at or near epicenter.
– Rails are folded, underground wires broken.
– Earthquakes originate sea waves called Tsunamis.
– Earthquakes result in the formation of cracks and
fissures on the ground formation.
– The earthquakes cause landslides.
– Landslide due to earthquake may block valleys to form
lakes

273. Seismic zones in india