182 ENVIRONMENTAL SCIENCE
The secondary response should include:
Reconstruction of houses, equipment and tools, supply
Creation of employment, of animals, and assist with
Assistance to farmers, recovery of small business
Distribution of farm and fisheries.Flood Problem In India
The nature of flood problem varies from one river system to another. Two great river
systems are discussed below considering the flood problems in India:
Brahmputra River
The main problem of flooding in the northeastern region arises from the Brahmaputra
river and its tributaries. The river in monsoon season overflows its banks and causes a great
damage to life and property both. Several times it has affected Kaziranga wildlife sanctuary
where rhinoceros population died due to rising floods. In recent years, the erosion along the
banks of the Brahmputra has assumed serious proportions. The rivers also carry considerable
amount of silt and have a tendency to change its course.
Ganga River System
In this region the northern tributaries of the Ganga, namely the Rapti, the Sharada,
the Ghaghra and the Gandak cause extensive flooding along their banks. Drainage congestion
is confined to the northwestern parts of U.P., Meerut, Mathura and Agra suffers the most.
Bihar suffers a considerable amount of damage due to the flooding of the Burhi Gandak, the
Baghirati, the Kamla Balan, the Kosi and the Mahananda. In addition to the crop submergence
the area experiences traffic dislocation also. In the Bengal region Baghirati, the Ajoy and
the Damodar cause extensive flooding. Here the tidal effect of Bay of Bengal also plays a
role in flooding. In Delhi and Haryana it is the Yamuna, the biggest tributary of the Ganga,
which causes a marginal amount of flooding. Most of these flooding regions suffer from
inadequate channel capacity as well as regulation of river water flow in these channels.
Earthquakes and Seismology
An earthquake is a major demonstration of the power of the tectonic forces caused by
endogenetic thermal conditions of the interior of the earth. An earthquake is a motion of the
ground surface, ranging from a faint tremor to a wild motion capable of shaking buildings
apart and causing gaping fissures to open in the ground. The Richter scale devised by
Charles F. Richter in 1935 measures the magnitude or intensity of energy released by an
earthquake. Good Friday Earthquake of March 27, 1964 in Alaska (USA) measuring 8.4 to
8.6 on Richter scale is among the greatest earthquakes of the world ever recorded.
The science that studies the behaviour and patterns of seismic waves is called seismology.
The place of origin of an earthquake is called focus, which is always hidden inside the earth,
but its depth varies from place to place. The place of the origin of an earthquake is called
‘focus’ which is always hidden inside the earth. The deepest earthquake may have its focus
at a depth of even 700 km below the ground surface. Major Himalayan earthquakes, such
as the Bihar-Nepal earth quake of August 2, 1988, have their focus around 20-30 km deep.
The place on the ground surface, which is perpendicular to the buried ‘focus’ or ‘hypocenter’,