2. Fieldwork is an important aspect of geology.
Learning to identify rocks in the field as well as
make geologic maps and cross-sections are
some of the fundamental skills a geologist must
Fieldwork also allows students to develop
critical thinking and problem solving skills
through direct experiential learning.
During this field school, students will be taught
basic geologic field methods through daily
exercises and will come out with an
understanding of the uses of these methods.
3. The purpose of any geological field mapping is to make a
geological description of an area & to collect rock
The data to be collected will to some degree depend on the type of
the project, but an exact geological description will always be of
During the mapping it is often necessary to take samples of rocks
and minerals for analysis in the laboratory.
The data from the field mapping should be presented in a report. In
the description it is important to distinguish clearly between the
direct observations and the evaluation of these observations.
The report from the field mapping should try to answer the
questions proposed by the client. It is also important to point out the
uncertainties concerning the conclusions and provide
recommendations for further investigations to get more reliable
GEOLOGICAL FIELD MAPPING
4. Mapping projects allow field
Geologist to develop
advanced skills in topographic
map reading, geologic
observation, and the
construction of geologic maps
THE PRIMARY FOCUS OF
5. GEOLOGIC CROSS SECTION
is a cross-sectional view along a line drawn
through a portion of a geologic map.
In other words, if you could slice through a portion of the earth, pull
away one half, and look at it from the side, the surface would be a
geologic cross section.
is very useful for geologists when analyzing
10. Geological fieldwork involves some level of risk; one part of this may come
from chance events that are unpredictable and little can be done about it;
another part of the risk, however, can be greatly reduced by awareness of
hazards and good judgements based on experience.
Persons undertaking field work must assess the risk, as far as possible, and
this will vary in accordance with weather, cliff and sea conditions on the day
and the experience, age, fitness and other characteristics of the persons.
Appropriate safety and first-aid equipment should be taken, and ideally
mobile phones should be available.
Permission should be sought for entry into private land and clearly no
damage should take place.
Attention should be paid to weather warnings, local warnings and danger
11. TO MAKE A GEOLOGICAL MAP YOU NEED A
TOPOGRAPHY MAP ON WHICH TO PLOT THE
GEOLOGICAL OBSERVATIONS IN THE FIELD
12. Geological reconnaissance maps
◦ Big scale; 1:250,000 (photogeology,
aerial photographs); less ground
Regional geological maps
◦ More detail; work based on 1:50,000
OR 1:25,000 result probably
Detailed geological maps
◦ Detailed geological map (1:10,000
◦ To provide records of specific
geological features in great details;
research as well as engineering or
other economic purposes
TYPES OF GEOLOGICAL MAP
16. Very important factor
◦ Must be big enough to see the features
◦ Must be small enough to minimize the no of photos
1:50,000 – 1:100,000 – cover very large area – best for
feasibility studies, choose “area of interest” etc
1:20,000 – 1:25,000 – produce mosaic of “area of interest”,
route selection, terrain evaluation & landuses.
1:10,000-1:15,000 – Ideal for detail photo interpretation.
1:2,500-1:5,000 – Large scale plan production.
17. HOW TO LOCATE?
There are three method can be used depending to the terrain
• Triangulate (use compass to take bearings on three
prominent features). Aim for small (< 1mm) triangle of
• Pace and bearing (traversing). Pace out distance from
known feature marked on map (use compass to take
bearing on feature and mark faintly on map so line can
easily be removed)
• GPS - widely used in industry and extremely very popular.
On a 1:10,000 map, 1 cm on the map represents 100 m
in the field. You should be able to pinpoint yourself within
10 m in the field, so when you translate this to the map,
the margin for error is 1 mm
Remember, when mapping at 1:10,000 scale, millimetre
accuracy is expected
1 Carbonaceous shale outcrop. B/S= 330/47NE.
2 As above. B/S= 320/45NE. Silt and concentrate
3 Interbedded carbonaceous shale and thinly
layered gray sandstone. B/S= 300/40 NE. Stream
4 Outcrop of massive sandstone, yellowish gray.
B/S= 310/45NE. Clearly displays thinly laminated
5 As above. B/S= 330/65NE
6 Carbonaceous shale outcropping at waterfall.
B/S= 290/65NNE. Bivalve fossils are spotted with
complete preservation. Fossil sample.
7 Huge outcrop of gray sandstone. B/S= 70/70SE.
8 As above. B/S= 45/75SE. Silt sample
9 Small outcrop of carbonaceous shale. B/S=
10 As above. B/S= 55/60SE
11 As above. Big outcrop of interbedded shale and
sandstone with folding. B/S= 330/56NE
12 Outcrop of massive calc-silicate hornfels. F/S=
300/56SE. Rock sample
METHODOLOGY TO CAPTURE MAP
A = QT 172213
B = QT 175215
C = QT 173220
D = QT 177210
E = QT 180213
Map references are the
spatial data for digital
mapping via GIS. It
shows the exact
location on map using
Easting & Northing
Spend some time looking at the exposure. What is the
rock type? Mineral composition? Grain size? Texture?
Geological structure? Bedding? Foliation? Tectonic
fabric? Fractures? Sedimentary structures? Fossils?
Observations are recorded in two
• On the field or base map (field
sheet or slip)
• In the field notebook
(information which cannot be
accommodated on the field
Map data is also normally recorded
in the field notebook using a
locality number reference system
on the map and a grid reference in
the field notebook. Thus you can
navigate between the two.
23. STRIKE & DIP
Strike line formed by the intersection of imaginary horizontal
plane with inclined surface. The reading (azimuth) is within the
range of 0o to 360o.
Dip is an inclination of plane measured perpendicular to the
strike line. It reads within the range of 0o to 90o.
Remember: Strike & dip tell you the orientation on map.
Readings should be correctly measured by using compass with
an appropriate principle. Data captured will process by various
32. Geohazards – Volcanic hazards
La Palma, Spain
33. Geohazards - Earthquakes
Measured by magnitude & intensity
Earthquake wave components – P, S, L, R
Greatest loss of life for geohazards e.g.
• Aleppo, Syria 1138, 230,000 dead
• Shaanxi, China 1556, 830,000 dead
• Lisbon, Portugal 1755, 100,000 dead
• Gansu, China 1920, 200,000 dead
• Tokyo, Japan 1923, 140,000 dead
• Tangshan, China 1976, 242,000 dead
• Sumatra, Indonesia 2004, 230,000 dead
Knock-on effects = Tsunamis, landslides, fires, diseases, famine, etc.
Latest death toll is 96 life @ M
8.1 on 8 Sept 2017 in Southern
Mexico – the most powerful ..
39. 2015 Sabah Earthquake
Date 5 June 2015
Origin time 07:15:43 MST (UTC+08:00)
Duration 30 seconds
Magnitude 6.0 (Mw) (USGS)
5.9 (Mw) (MetMalaysia)
Depth 10 km
Epicenter 5.980°N 116.525°E
Areas affected West Coast & Interior Division
(Mount Kinabalu area), Sabah
Total damage Building and infrastructure damage,
landslides & geological changes,
$2.84 billion (USD)
Max. intensity VII (Very strong)
Aftershocks 130 (As of 1 April 2016)
Casualties 18 deaths; 11 wounded
40. Geohazards - Earthquakes
Historic data collection and collation
Historic data collection and collation
Building susceptibility (homes, hospitals, public offices…)
Infrastructure susceptibility (road, bridges, sewerage…)
Utility conduits (gas, power, water, telecommunications…)
Industry (refineries, biohazards, nuclear hazards…)
Emergency services (police, ambulance, fire…)
44. Mitigation measures on slope stabilization
3. Drain the slope
1. Retain the slope
2. Unload the slope
4. Anchor the slope
45. Simpang Pulai – Cameron Highlands
46. A landslide occurred around 2.00am of 16 December 2022 near the Batang Kali,
Selangor, displacing 450,000 m3 of soil and burying campsites at an organic farm.
The accident trapped 92 people under the collapsed slope; most were campers
from the farm. Thirty-one people were killed and 61 were rescued.
48. Rockfall incident happened at 9.15am on 8 March 2022, claimed two life and two
injured at Simpang Pulai, Ipoh. There were two excavators buried under the huge
boulders rolled down from the quarry face, weighing 50 to 100 tonnes.
51. Erosion mechanics
Universal Soil Loss Equation
Annual soil loss (t/ha/yr)
= Rainfall erosivity
x soil erodibility
x slope length
x slope gradient
x support practice factor
x cover and crop management
Channels < 0.3m depth
Channels > 0.3m depth
Soil aggregate stability
(slaking and dispersion)
Geohazards – Soil erosion by water
57. Mexico City
• Subsidence due to groundwater
extraction threatens historic buildings
such as the cathedral (1573 – 1813).
• Similar thing happen in Bangkok upon the
over-pumping of groundwater led to
subsidence. Now Bangkok is almost
below sea level.
About 1m recent subsidence
Plumb-bob to check restoration success
58. Geohazards – Acid sulfate soils
Acid sulfate soils (ASS)
Coastal ASS (CASS)
Inland ASS (IASS)
Potential ASS (PASS)
Actual ASS (AASS)
Contain iron sulfides (e.g. pyrite)
Produce sulfuric acid when disturbed
Severe damage to built and natural environment
Often contaminate soils with other toxins
AASS has pH <4
60. Geohazards – Reactive soils
• Soils which swell when wetted and
shrink when dried.
• Victoria’s most prevalent geohazard
• Costs $millions per year in damage to
houses, roads, utility services, etc.
• Whole industry dedicated to soil tests
• Australian Standard AS2870
• Soils which contain certain clay
minerals usually montmorillonite, but
may be others.
• Easily identified by soil classification
• Managed by building codes and
specialist engineering solutions.
• Can be stabilised by the use of soil
Landscapes are dynamic. Geohazards are natural
Identify the processes that occur in different landscapes,
and the main factors (natural or man-made) that are
acting on those processes
Assess the risk to assets (life, property, environment,
Where risk is unacceptable, reduce the risk by
changing the likelihood of an event or its consequence
Geohazards can also be man-made (anthropogenic)