Seismology:- It is deals with the every aspect of an earthquake, Whether its about its generation of earthquake its propagation of its waves in any direction and recording of waves releases during earthquake etc. It also deals with the causes of earthquake whether it is due to natural or artificial.
Now lets understand major terms related to Seismology:-
1) Earthquake:- Earthquake is nothing but the movement of earth surface due to release of seismic waves which originates below the earth surface. It can be mild or severe based on its epicentre and epicentral distance.
Causes of movement of earth surface can be natural or manmade
Natural causes Manmade causes
i) Tectonic movement of plates i) Nuclear tests or explosives
ii) Volcanic eruption ii) Mining activities
iii) Land slides or rock fall iii) Heavy locomotives
iv) Bump of sea waves etc.
About 90% of earthquake is occur due to tectonic movement.
2) Focus or Seismic centre :- It is basically a point inside the earth surface from where the seismic energy releases, This point lies on the fault plane/rupture plane.
when accumulated strain exceed the capacity of tectonic plates there is a rupture occur in plane and due to this rupture huge energy releases which cause the movement of earth surface. Its position is determined based upon the seismographic records
3) Epicentre :- It is a point on the ground surface which is vertically above the focus. Here point means a portion of area vertically above the inside disturbed area. As we know earthquake cannot originate from a small point inside the earth hence point/focus means a whole disturbed area inside the earth which is responsible for earthquake.
Distance between epicentre and and focus is called focal depth which is used to categories the earthquake based on shallow, or deep earthquake.
4) Epicentral distance :- It is horizontal distance on the earth surface from the epicentre to any point of destruction so as you can see in below image as the epicentral distance increase the intensity of earthquake decrease and it become weak and ultimately die out.
5) Anticentre :- It is point on the surface or earth which is vertically opposite to the epicentre. It is not that much important in seismology because there is very little disturbance on anticentre area thats why we do not give that much importance in analysing this beam.
6) Seismic waves :- The waves transmitted in all direction due to strain energy released from the focus due to fracture in tectonic plates during an earthquake. Seismic waves are of two types Body waves and surface waves.
7) Isoseismal lines :- These are the imaginary lines lying on the earth surface along which the earthquake intensity is same at every point. It is same as Contour line ( show same height) or Isogonic lines (show same declination) and a map showing different isoseismal line is called isoseismal map. These lines are used for dividing area in different seismic zones based on earthquake magnitude.
Importance of seismology/Earthquake engineering
As we aware of the current scenario which is faced by all countries where probability of occurring of earthquake is very high like Japan, China etc. Occurring of earthquake is a siren for all engineers and designing authority to consider seismic factors in design. Due to the recent study most people die during an earthquake due to collapse of structures. These structures are not adequately fit for surviving the earthquake frequency.
The basic knowledge of civil/structural engineering without the knowledge of earthquake engineering is not sufficient to build safe structures from here the significance of earthquake engineering is came into existence.
The knowledge of earthquake engineering or seismology is thus essential:
- To design and build earthquake resistant structures.
- To Pre prepare our self for facing any devastating scenario.
- To carry out the research and development in earthquake field so that we can manage it wisely.
This is dummy text. It is not meant to be read. Accordingly, it is difficult to figure out when to end it. But then, this is dummy text. It is not meant to be read. Period.
1 Comments:
Click here for CommentsGood article for basic information about earthquake. 👍
Please do not Enter Spam link in comment box ConversionConversion EmoticonEmoticon