1. Seismic activity
2. Earth's magnetism
3. Volcanoes
4. Mined rocks
5. Gravitational force
6. Meteors
Seismic Activity: Frequency and size of earthquake.
Earth's magnetism: Due to the movement of molten material under the earth's crust.
Volcanoes: A rupture in the crust of a planetary mass object such as Earth, that allows hot lava, volcanic ash & gases to escape.
Mined Rocks: Excavating hard minerals.
Gravitational force: A natural phenomenon.
Meteors: A bright streak of light.

The word 'Tsunami' is a Japanese term, meaning harbour waves. It is adapted to describe large seismically generated sea waves caused by Earthquakes, submarine explosions and landslides. These waves travel at a great speed (more than 500 km per hour) and the length of the waves exceeds 600 km. These waves reach to a height of more than 15 m near the sea shore and are capable of causing destruction along the coastal area.
The 2004 Indian Ocean Earthquake that caused tsunami is.the sixth-deadliest natural disaster which travelled at a speed of 6.00km per hour with an estimated death toll of 2,80,000. The Earthquake which occurred near Indonesia at 00.58 hours took nearly 7 hours to reach Chennai.

Based on the periodicity of eruptions, volcanoes are classified into
(i) Active volcano,
(ii) Dormant volcano,
(iii) Extinct volcano.
(i) Active Volcano: Active volcanoes are those which constantly eject volcanic lava,gases and fragmented materials. (e.g.) Mount St. Helens in the United States.
(ii) Dormant Volcano: Volcanoes that do not show any sign of volcanic activity for a long period of time are known as dormant volcanoes. Sometimes there may be a sudden explosion which may cause unimaginable loss to life and property (e.g.) Mt. Fuji, Japan.
(iii) Extinct or Dead Volcano: When a volcano permanently stops its volcanic activity, then it is called as extinct or dead volcano (e.g.) Mt. Kilimanjaro, Tanzania.
Volcanoes can also be classified based on their structure and composition as composite volcano, shield volcano and dome volcano.

a) Pacific Ring of fire: It is a major area and an arc in the_basin of the Pacific ocean where many earthquakes and volcanic eruptions occur.

(b) Earthquake-prone zones (any two): Turkey, Indonesia

(c) Locate any two active volcanoes of the world: Hawaii-, Mount Fuji

(d) Himalayas and Alps ranges

The Ring of Fire is a ring of volcanoes around the Pacific Ocean. These volcanoes result from subduction of oceanic plates beneath lighter continental plates, A subduction zone is a place where one plate of oceanic lithosphere is shoved under another plate. As it is shoved into the hotter mantle the plate heats up. The addition of volatiles such as water to the hot overlying mantle causes partial melting and the production of magma. This magma rises up through the over-lying plate to erupt at the surface. Hence, the Pacific Ring of Fire is most seismically and volcanically active.

GPS works by sending radio signals from satellites to ground stations. The distance between the satellites and station is recorded. Over time, these distances change slightly. Scientists can measure the rate of Tectonic Plate movements by recording the time it takes for ground stations to move a given distance.