Topics to discuss
- Fall in Earth’s Seismic noise
- Amphan Cyclone
- Diamer-Bhasha Dam
WHY IN NEWS
Fall in Earth’s Seismic Noise
- Scientists at the British Geological Survey (BGS) have reported a change in the Earth’s seismic noise and vibrations amid the coronavirus lockdown.
- These findings have come two weeks after seismologists at the Royal Observatory in Belgium observed a 30-50% fall in levels of seismic noise since schools and businesses were closed in mid-March
- In geology (study of rocks), seismic noise refers to the relatively persistent vibration of the ground due to a multitude of causes.
- This noise includes vibrations caused due to human activity, such as transport and manufacturing.
- Scientists first observed this seismic noise — everything recorded on seismograms that cannot be attributed to earthquakes — at the end of the 19th century.
- It is the unwanted component of signals recorded by a seismometer and makes it difficult for scientists to study seismic data that is more valuable.
- Apart from geology, seismic noise is also studied in other fields such as oil exploration, hydrology, and earthquake engineering
- Since the lockdown, researchers have said that they were able to study natural vibrations even from surface readings, owing to lesser seismic noise.
- Due to lower noise levels, scientists are now hoping that they would be able to detect smaller earthquakes and tremors that had slipped past their instruments so far.
Q)Tropical cyclones are known with different names in different areas. Which of the statement is correct regarding the naming of tropical cyclones?
- A) Eastern and Central North Pacific: Hurricanes
- B) Western Northern Pacific Willy-Willy
- C) Southwest Australia Typhoons
- D) All of the above are matched correctly
WHY IN NEWS
- Recently, Cyclone ‘Amphan’ wreaked havoc in the eastern coastal states – West Bengal and Odisha.
More about news
- The storm is only the second super cyclone to form in the Bay of Bengal since 1999.
- According to Indian Meteorological Department (IMD), tropical cyclone with wind speed more than 222 km/hr is a super cyclone (highest in Classification).
- The rapid intensification of Amphan is an indication of warming of Bay of Bengal which registered maximum surface temperatures of 32-34°C.
Basic about Tropical Cyclone
- Tropical cyclones are violent storms that originate over oceans in tropical areas and move over to the coastal areas bringing about large scale destruction caused by violent winds
- The energy that intensifies the storm, comes from the condensation process
- With continuous supply of moisture from the sea, the storm is further strengthened.
- On reaching the land the moisture supply is cut off and the storm dissipates.
- The place where a tropical cyclone crosses the coast is called the landfall of the cyclone.
Conditions for Tropical Cyclones
- The conditions favorable for the formation and intensification of tropical storms are:
(i) Large sea surface with temperature higher than 27° C
(ii) Presence of the Coriolis force
(iii) Small variations in the vertical wind speed
(iv) A pre-existing weak low-pressure area or low-level-cyclonic circulation
(v) Upper divergence above the sea level system.
Different names for Tropical cyclones
Q) Diamer-Bhasha dam is located on which of the following river
WHY IN NEWS
- Recently, Pakistan signed a contract with a joint venture of a China Power (Chinese state-run firm) and the Frontier Works Organisation (FWO-a commercial arm of Pakistan’s military) for the construction of the Diamer-Bhasha dam.
- The Diamer-Bhasha Dam is located on the Indus River in northern Pakistan between Kohistan district in Khyber Pakhtunkhwa and Diamer district in Gilgit Baltistan.
- The dam will have a gross storage capacity of 8.1 Million Acre Feet (MAF) and power generation capacity of 4500 MW.
- It will be the tallest Roller Compact Concrete (RCC) dam in the world with the height of 272 meters, .
- The dam project with a total financial outlay of about 1,406.5 billion Pakistani rupees would be completed in 2028
- The project was approved in 2010, but it suffered delays because international lending agencies backtracked due to the opposition from India as a major part of the dam is located in Gilgit-Baltistan (one of the disputed territories of India) and it will cause unrest in the region
- India has opposed the move on the grounds that Gilgit-Baltistan region is part of the erstwhile state of Jammu and Kashmir that was illegally occupied by Pakistan.
- India has consistently conveyed her protest and shared concerns with both China and Pakistan on all such projects in the Indian territories under Pakistan’s illegal occupation