Sources of Interior of Earth - Notes | Geography for UPSC 2024 (Pre & Mains) PDF Download

 Page 1


 
SOURCES OF INFORMATION ABOUT THE INTERIOR 
DIRECT SOURCES  
Surface rocks or Rocks from the mining areas. 
The most easily available solid earth material is surface rock or the rocks 
we get from mining areas.  Gold mines in South Africa are as deep as 3 
- 4 km.  
 
Information from deep sea drilling project 
Information from integrated ocean drilling project. 
Other deep drilling projects. 
Besides mining, scientists have taken up a number of projects to penetrate 
deeper depths to explore the conditions in the crustal portions. Scientists 
world over are working on two major projects such as “Deep Ocean Drilling 
Project” and “Integrated Ocean Drilling Project”. 
 The deepest drill at Kola, in Arctic Ocean, has so far reached a depth of 12 
km ( as per content in NCERT). This and many deep drilling projects have 
provided large volume of information through the analysis of materials collected 
at different depths.  
ADDITIONAL INFO: 
PROJECT MOHOLE 
 
Project Mohole was an attempt in the early 1960s to drill through the 
Earth's crust to obtain samples of the Mohorovic discontinuity, or 
Moho, the boundary between the Earth's crust and mantle. The project 
was to provide an Earth Science complement to the high-profile Space 
Race. The project was initially led by a group of scientists called the 
American Miscellaneous Society with funding from the National Science 
Foundation. The project suffered from political and scientific battles, 
mismanagement, and cost over-runs, and the U.S. House of 
Page 2


 
SOURCES OF INFORMATION ABOUT THE INTERIOR 
DIRECT SOURCES  
Surface rocks or Rocks from the mining areas. 
The most easily available solid earth material is surface rock or the rocks 
we get from mining areas.  Gold mines in South Africa are as deep as 3 
- 4 km.  
 
Information from deep sea drilling project 
Information from integrated ocean drilling project. 
Other deep drilling projects. 
Besides mining, scientists have taken up a number of projects to penetrate 
deeper depths to explore the conditions in the crustal portions. Scientists 
world over are working on two major projects such as “Deep Ocean Drilling 
Project” and “Integrated Ocean Drilling Project”. 
 The deepest drill at Kola, in Arctic Ocean, has so far reached a depth of 12 
km ( as per content in NCERT). This and many deep drilling projects have 
provided large volume of information through the analysis of materials collected 
at different depths.  
ADDITIONAL INFO: 
PROJECT MOHOLE 
 
Project Mohole was an attempt in the early 1960s to drill through the 
Earth's crust to obtain samples of the Mohorovic discontinuity, or 
Moho, the boundary between the Earth's crust and mantle. The project 
was to provide an Earth Science complement to the high-profile Space 
Race. The project was initially led by a group of scientists called the 
American Miscellaneous Society with funding from the National Science 
Foundation. The project suffered from political and scientific battles, 
mismanagement, and cost over-runs, and the U.S. House of 
 
Representatives discontinued funding for the project in 1966. By then 
a program of sediment drilling had branched from Project Mohole to 
become the Deep Sea Drilling Project of the National Science Foundation 
DEEP SEA DRILLING PROJECT 
The Deep-Sea Drilling Project (DSDP) was a scientific program for drilling 
cores of sediment and basaltic crust beneath the deep oceans and recovering 
them for study. The drilling began in 1968, using the ship Glomar Challenger, 
and ended in 1983. The DSDP, which was succeeded in 1984 by the Ocean 
Drilling Program, was itself a successor to the unsuccessful Mohole Project in 
which scientists attempted to drill an extremely deep hole reaching to the Earth's 
mantle. 
OCEAN DRILLING PROGRAM 
Ocean drilling program is an international effort to explore and study 
the composition and structure of the earth’s ocean basins. It began in 
1985. Several countries participated. In 2004, ODP transformed into 
Integrated Ocean Driling Program 
INTEGRATED OCEAN DRILING PROGRAM 
It is an international marine research program. It used heavy drilling 
equipment to monitor and sample sub-seafloor environments. With this 
research, IODP documented environmental change, earth processes and 
effects, the biosphere, solid earth cycles, geodynamics.It brought together 
scientists from different countries. National consortia and government 
funding agencies supported IODP (international ocean discovery program). 
The program began a new 10-year phase with the International Ocean 
Discovery Program, from the end of 2013. 
India joined the IODP, as an associate member during 2008-09. 
In india, the participating insititute is national centre for Antarctic and 
ocean research, Goa. 
 
Page 3


 
SOURCES OF INFORMATION ABOUT THE INTERIOR 
DIRECT SOURCES  
Surface rocks or Rocks from the mining areas. 
The most easily available solid earth material is surface rock or the rocks 
we get from mining areas.  Gold mines in South Africa are as deep as 3 
- 4 km.  
 
Information from deep sea drilling project 
Information from integrated ocean drilling project. 
Other deep drilling projects. 
Besides mining, scientists have taken up a number of projects to penetrate 
deeper depths to explore the conditions in the crustal portions. Scientists 
world over are working on two major projects such as “Deep Ocean Drilling 
Project” and “Integrated Ocean Drilling Project”. 
 The deepest drill at Kola, in Arctic Ocean, has so far reached a depth of 12 
km ( as per content in NCERT). This and many deep drilling projects have 
provided large volume of information through the analysis of materials collected 
at different depths.  
ADDITIONAL INFO: 
PROJECT MOHOLE 
 
Project Mohole was an attempt in the early 1960s to drill through the 
Earth's crust to obtain samples of the Mohorovic discontinuity, or 
Moho, the boundary between the Earth's crust and mantle. The project 
was to provide an Earth Science complement to the high-profile Space 
Race. The project was initially led by a group of scientists called the 
American Miscellaneous Society with funding from the National Science 
Foundation. The project suffered from political and scientific battles, 
mismanagement, and cost over-runs, and the U.S. House of 
 
Representatives discontinued funding for the project in 1966. By then 
a program of sediment drilling had branched from Project Mohole to 
become the Deep Sea Drilling Project of the National Science Foundation 
DEEP SEA DRILLING PROJECT 
The Deep-Sea Drilling Project (DSDP) was a scientific program for drilling 
cores of sediment and basaltic crust beneath the deep oceans and recovering 
them for study. The drilling began in 1968, using the ship Glomar Challenger, 
and ended in 1983. The DSDP, which was succeeded in 1984 by the Ocean 
Drilling Program, was itself a successor to the unsuccessful Mohole Project in 
which scientists attempted to drill an extremely deep hole reaching to the Earth's 
mantle. 
OCEAN DRILLING PROGRAM 
Ocean drilling program is an international effort to explore and study 
the composition and structure of the earth’s ocean basins. It began in 
1985. Several countries participated. In 2004, ODP transformed into 
Integrated Ocean Driling Program 
INTEGRATED OCEAN DRILING PROGRAM 
It is an international marine research program. It used heavy drilling 
equipment to monitor and sample sub-seafloor environments. With this 
research, IODP documented environmental change, earth processes and 
effects, the biosphere, solid earth cycles, geodynamics.It brought together 
scientists from different countries. National consortia and government 
funding agencies supported IODP (international ocean discovery program). 
The program began a new 10-year phase with the International Ocean 
Discovery Program, from the end of 2013. 
India joined the IODP, as an associate member during 2008-09. 
In india, the participating insititute is national centre for Antarctic and 
ocean research, Goa. 
 
 
INTERNATIONAL OCEAN DISCOVERY PROGRAM 
The International Ocean Discovery Program (IODP) is an international 
marine research collaboration dedicated to advancing scientific 
understanding of the Earth through drilling, coring, and monitoring 
the subseafloor. The research enabled by IODP samples and data 
improves scientific understanding of changing climate and ocean 
conditions, the origins of ancient life, risks posed by geohazards, and 
the structure and processes of Earth's tectonic plates and uppermost 
mantle.  
 
IODP began in 2013 and builds on the research of four previous 
scientific ocean drilling programs: Project Mohole, Deep Sea Drilling 
Project, Ocean Drilling Program, and Integrated Ocean Drilling 
Program.  
 
Together, these programs represent the longest running and most 
successful international Earth science collaboration. 
Volcanic eruptions 
Volcanic eruption forms another source of obtaining direct information. As 
and when the molten material (magma) is thrown onto the surface of the 
earth, during volcanic eruption it becomes available for laboratory 
analysis. However, it is difficult to ascertain the depth of the source of such 
magma. 
 
 
 
 
 
Page 4


 
SOURCES OF INFORMATION ABOUT THE INTERIOR 
DIRECT SOURCES  
Surface rocks or Rocks from the mining areas. 
The most easily available solid earth material is surface rock or the rocks 
we get from mining areas.  Gold mines in South Africa are as deep as 3 
- 4 km.  
 
Information from deep sea drilling project 
Information from integrated ocean drilling project. 
Other deep drilling projects. 
Besides mining, scientists have taken up a number of projects to penetrate 
deeper depths to explore the conditions in the crustal portions. Scientists 
world over are working on two major projects such as “Deep Ocean Drilling 
Project” and “Integrated Ocean Drilling Project”. 
 The deepest drill at Kola, in Arctic Ocean, has so far reached a depth of 12 
km ( as per content in NCERT). This and many deep drilling projects have 
provided large volume of information through the analysis of materials collected 
at different depths.  
ADDITIONAL INFO: 
PROJECT MOHOLE 
 
Project Mohole was an attempt in the early 1960s to drill through the 
Earth's crust to obtain samples of the Mohorovic discontinuity, or 
Moho, the boundary between the Earth's crust and mantle. The project 
was to provide an Earth Science complement to the high-profile Space 
Race. The project was initially led by a group of scientists called the 
American Miscellaneous Society with funding from the National Science 
Foundation. The project suffered from political and scientific battles, 
mismanagement, and cost over-runs, and the U.S. House of 
 
Representatives discontinued funding for the project in 1966. By then 
a program of sediment drilling had branched from Project Mohole to 
become the Deep Sea Drilling Project of the National Science Foundation 
DEEP SEA DRILLING PROJECT 
The Deep-Sea Drilling Project (DSDP) was a scientific program for drilling 
cores of sediment and basaltic crust beneath the deep oceans and recovering 
them for study. The drilling began in 1968, using the ship Glomar Challenger, 
and ended in 1983. The DSDP, which was succeeded in 1984 by the Ocean 
Drilling Program, was itself a successor to the unsuccessful Mohole Project in 
which scientists attempted to drill an extremely deep hole reaching to the Earth's 
mantle. 
OCEAN DRILLING PROGRAM 
Ocean drilling program is an international effort to explore and study 
the composition and structure of the earth’s ocean basins. It began in 
1985. Several countries participated. In 2004, ODP transformed into 
Integrated Ocean Driling Program 
INTEGRATED OCEAN DRILING PROGRAM 
It is an international marine research program. It used heavy drilling 
equipment to monitor and sample sub-seafloor environments. With this 
research, IODP documented environmental change, earth processes and 
effects, the biosphere, solid earth cycles, geodynamics.It brought together 
scientists from different countries. National consortia and government 
funding agencies supported IODP (international ocean discovery program). 
The program began a new 10-year phase with the International Ocean 
Discovery Program, from the end of 2013. 
India joined the IODP, as an associate member during 2008-09. 
In india, the participating insititute is national centre for Antarctic and 
ocean research, Goa. 
 
 
INTERNATIONAL OCEAN DISCOVERY PROGRAM 
The International Ocean Discovery Program (IODP) is an international 
marine research collaboration dedicated to advancing scientific 
understanding of the Earth through drilling, coring, and monitoring 
the subseafloor. The research enabled by IODP samples and data 
improves scientific understanding of changing climate and ocean 
conditions, the origins of ancient life, risks posed by geohazards, and 
the structure and processes of Earth's tectonic plates and uppermost 
mantle.  
 
IODP began in 2013 and builds on the research of four previous 
scientific ocean drilling programs: Project Mohole, Deep Sea Drilling 
Project, Ocean Drilling Program, and Integrated Ocean Drilling 
Program.  
 
Together, these programs represent the longest running and most 
successful international Earth science collaboration. 
Volcanic eruptions 
Volcanic eruption forms another source of obtaining direct information. As 
and when the molten material (magma) is thrown onto the surface of the 
earth, during volcanic eruption it becomes available for laboratory 
analysis. However, it is difficult to ascertain the depth of the source of such 
magma. 
 
 
 
 
 
 
INDIRECT SOURCES  
Based on known paramteres 
Assessment of temperature, pressure and density based on the 
known parameters up to some distance. 
We know through the mining activity that temperature and 
pressure increase with the increasing distance from the surface 
towards the interior in deeper depths. Moreover, it is also known 
that the density of the material also increases with depth. It is 
possible to find the rate of change of these characteristics. Knowing 
the total thickness of the earth, scientists have estimated the values 
of temperature, pressure and the density of materials at different 
depths. 
Meteorite 
Meteorites, because the material and the structure observed is 
similar to the earth. These are solid bodies developed out of 
meteoroids same as or similar to our planet. material that 
becomes available for analysis from meteors, is not from the 
interior of the earth. The material and the structure observed 
in the meteors are similar to that of the earth. They are solid 
bodies developed out of materials same as, or similar to, our planet. 
Hence, this becomes yet another source of information about the 
interior of the earth. 
 
Gravitation, Magnetic Field, And Seismic Activity.  
 
Gravitation 
The gravitation force (g) is not the same at different latitudes on the 
surface. It is greater near the poles and less at the equator. This is 
because of the distance from the centre at the equator being greater 
Page 5


 
SOURCES OF INFORMATION ABOUT THE INTERIOR 
DIRECT SOURCES  
Surface rocks or Rocks from the mining areas. 
The most easily available solid earth material is surface rock or the rocks 
we get from mining areas.  Gold mines in South Africa are as deep as 3 
- 4 km.  
 
Information from deep sea drilling project 
Information from integrated ocean drilling project. 
Other deep drilling projects. 
Besides mining, scientists have taken up a number of projects to penetrate 
deeper depths to explore the conditions in the crustal portions. Scientists 
world over are working on two major projects such as “Deep Ocean Drilling 
Project” and “Integrated Ocean Drilling Project”. 
 The deepest drill at Kola, in Arctic Ocean, has so far reached a depth of 12 
km ( as per content in NCERT). This and many deep drilling projects have 
provided large volume of information through the analysis of materials collected 
at different depths.  
ADDITIONAL INFO: 
PROJECT MOHOLE 
 
Project Mohole was an attempt in the early 1960s to drill through the 
Earth's crust to obtain samples of the Mohorovic discontinuity, or 
Moho, the boundary between the Earth's crust and mantle. The project 
was to provide an Earth Science complement to the high-profile Space 
Race. The project was initially led by a group of scientists called the 
American Miscellaneous Society with funding from the National Science 
Foundation. The project suffered from political and scientific battles, 
mismanagement, and cost over-runs, and the U.S. House of 
 
Representatives discontinued funding for the project in 1966. By then 
a program of sediment drilling had branched from Project Mohole to 
become the Deep Sea Drilling Project of the National Science Foundation 
DEEP SEA DRILLING PROJECT 
The Deep-Sea Drilling Project (DSDP) was a scientific program for drilling 
cores of sediment and basaltic crust beneath the deep oceans and recovering 
them for study. The drilling began in 1968, using the ship Glomar Challenger, 
and ended in 1983. The DSDP, which was succeeded in 1984 by the Ocean 
Drilling Program, was itself a successor to the unsuccessful Mohole Project in 
which scientists attempted to drill an extremely deep hole reaching to the Earth's 
mantle. 
OCEAN DRILLING PROGRAM 
Ocean drilling program is an international effort to explore and study 
the composition and structure of the earth’s ocean basins. It began in 
1985. Several countries participated. In 2004, ODP transformed into 
Integrated Ocean Driling Program 
INTEGRATED OCEAN DRILING PROGRAM 
It is an international marine research program. It used heavy drilling 
equipment to monitor and sample sub-seafloor environments. With this 
research, IODP documented environmental change, earth processes and 
effects, the biosphere, solid earth cycles, geodynamics.It brought together 
scientists from different countries. National consortia and government 
funding agencies supported IODP (international ocean discovery program). 
The program began a new 10-year phase with the International Ocean 
Discovery Program, from the end of 2013. 
India joined the IODP, as an associate member during 2008-09. 
In india, the participating insititute is national centre for Antarctic and 
ocean research, Goa. 
 
 
INTERNATIONAL OCEAN DISCOVERY PROGRAM 
The International Ocean Discovery Program (IODP) is an international 
marine research collaboration dedicated to advancing scientific 
understanding of the Earth through drilling, coring, and monitoring 
the subseafloor. The research enabled by IODP samples and data 
improves scientific understanding of changing climate and ocean 
conditions, the origins of ancient life, risks posed by geohazards, and 
the structure and processes of Earth's tectonic plates and uppermost 
mantle.  
 
IODP began in 2013 and builds on the research of four previous 
scientific ocean drilling programs: Project Mohole, Deep Sea Drilling 
Project, Ocean Drilling Program, and Integrated Ocean Drilling 
Program.  
 
Together, these programs represent the longest running and most 
successful international Earth science collaboration. 
Volcanic eruptions 
Volcanic eruption forms another source of obtaining direct information. As 
and when the molten material (magma) is thrown onto the surface of the 
earth, during volcanic eruption it becomes available for laboratory 
analysis. However, it is difficult to ascertain the depth of the source of such 
magma. 
 
 
 
 
 
 
INDIRECT SOURCES  
Based on known paramteres 
Assessment of temperature, pressure and density based on the 
known parameters up to some distance. 
We know through the mining activity that temperature and 
pressure increase with the increasing distance from the surface 
towards the interior in deeper depths. Moreover, it is also known 
that the density of the material also increases with depth. It is 
possible to find the rate of change of these characteristics. Knowing 
the total thickness of the earth, scientists have estimated the values 
of temperature, pressure and the density of materials at different 
depths. 
Meteorite 
Meteorites, because the material and the structure observed is 
similar to the earth. These are solid bodies developed out of 
meteoroids same as or similar to our planet. material that 
becomes available for analysis from meteors, is not from the 
interior of the earth. The material and the structure observed 
in the meteors are similar to that of the earth. They are solid 
bodies developed out of materials same as, or similar to, our planet. 
Hence, this becomes yet another source of information about the 
interior of the earth. 
 
Gravitation, Magnetic Field, And Seismic Activity.  
 
Gravitation 
The gravitation force (g) is not the same at different latitudes on the 
surface. It is greater near the poles and less at the equator. This is 
because of the distance from the centre at the equator being greater 
 
than that at the poles.  
 
The gravity values also differ according to the mass of material. The 
uneven distribution of mass of material within the earth influences this 
value.  
 
Magnetic Surveys 
Magnetic methods are based upon measuring the magnetic effects 
produced by varying concentrations of ferromagnetic minerals, 
such as magnetite, in geological formations. 
 
Seismic Activity 
Seismic activity is one of the most important sources of information 
about the interior of the earth. 
Geologists use seismic (earthquake) waves to determine the 
depths of layers of molten and molten material within Earth. 
Because different types of earthquake waves behave differently 
when they encounter material in different states (for example, 
molten, semi-molten, solid), seismic stations established around 
Earth detect and record the strengths of the different types of 
waves and the directions from which they came. Geologists use 
these records to establish the structure of Earth's interior.