Relationship Geophysics & Natural Disasters

Relationship b/w Geophysics & Natural Disasters

1. Title; Geophysics and Natural Disasters. Understanding and predicting earthquakes, tsunamis , and other natural disasters. Teacher Dr.Irfan M.Bilawal Khan 29121 H.Suleman Habib 29201

2. Contents. Introduction to Geo physics Natural disaster Different types of Natural disasters . Understanding and predicting earthquakes Tsunamis

3. Introduction To GEO PHYSICS. Geophysics is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis . Geophysics is the study of the physics of the Earth and its environment in space. One emphasis is the exploration of the Earth's interior using physical properties measured at or above the Earth's surface, together with mathematical models to predict those properties.

4. Natural disaster Any calamitous occurrence generated by the effects of natural, rather than human-driven, phenomena that produces great loss of human life or destruction of the natural environment, private property, or public infrastructure. A natural disaster may be caused by weather and climate events or by earthquakes, landslides, and other occurrences that originate at Earth’s surface or within the planet itself. No spot on Earth is immune from a natural disaster; however, certain types of disasters are often limited to or occur more frequently in specific geographic regions.

5. Different types of Natural disasters. Flood Drought Wildfires Heat wave Wind or wind storms Earthquakes Winter and ice storms Landslides

6. Why Do Earthquakes Happen? Although the Earth looks like a pretty solid place from the surface, it’s actually extremely active just below the surface. The Earth is made of four basic layers: a solid crust, a hot, nearly solid mantle, a liquid outer core and a solid inner core. The solid crust and top, stiff layer of the mantle make up a region called the lithosphere. The lithosphere isn’t a continuous piece that wraps around the whole Earth like an eggshell. It’s actually made up of giant puzzle pieces called tectonic plates. Tectonic plates are constantly shifting as they drift around on the viscous, or slowly flowing, mantle layer below.

7. Why Do Earthquakes Happen? This non-stop movement causes stress on Earth’s crust. When the stresses get too large, it leads to cracks called faults. When tectonic plates move, it also causes movements at the faults. An earthquake is the sudden movement of Earth’s crust at a fault line.

8. Why Do Earthquakes Happen? The location where an earthquake begins is called the epicenter. An earthquake’s most intense shaking is often felt near the epicenter. However, the vibrations from an earthquake can still be felt and detected hundreds, or even thousands of miles away from the epicenter.

9. Prediction of earthquakes We do not know how, and we do not expect to know how any time in the foreseeable future. USGS scientists can only calculate the probability that a significant earthquake will occur (shown on our hazard mapping) in a specific area within a certain number of years.( https://www.usgs.gov/faqs/can-you-predict-earthquakes#:~:text=We%20do%20not%20know%20how,a%20certain%20number%20of%20years ) A forecast tells you the chance or the probability of a range of future earthquakes in a given region. This includes how big the quakes may be (their magnitude), and how frequently they will occur over a specified time period. Earthquake forecasts are built on observations of past earthquake activity, which may stretch back decades, centuries or even thousands of years. These observations are analysed and modelled, and we use our understanding of the physics of earthquake occurrence to determine the chances of future seismic activity.

10. Prediction of earthquakes When looking at catalogues of the time, location and magnitude of past earthquakes, it becomes very clear that damaging earthquakes are more likely to strike along the boundaries of the tectonic plates that make up Earth’s crust than in the interior of those plates. In recent decades, the installation of worldwide networks of seismic recorders has also allowed the detection of much smaller quakes and tremors – including events too small to be perceived by people. These data have revealed important relationships between the relative numbers of small and large earthquakes which underpin earthquake forecasting. Earthquake forecasts can be made for the short term (weeks, months, years) and the long term (decades to centuries).

11. Tsunamis Tsunamis are giant waves caused by earthquakes or volcanic eruptions under the sea. Out in the depths of the ocean, tsunami waves do not dramatically increase in height. But as the waves travel inland, they build up to higher and higher heights as the depth of the ocean decreases. The speed of tsunami waves depends on ocean depth rather than the distance from the source of the wave. Tsunami waves may travel as fast as jet planes over deep waters, only slowing down when reaching shallow waters. While tsunamis are often referred to as tidal waves, this name is discouraged by oceanographers because tides have little to do with these giant waves.

12. Flood  flooding of the  Indus River  in  Pakistan  in late July and August 2010 that led to a humanitarian disaster considered to be one of the worst in Pakistan’s history. The floods, which affected approximately 20 million people, destroyed homes, crops, and  infrastructure  and left millions  vulnerable  to malnutrition and waterborne disease. Estimates of the total number of people killed ranged from 1,200 to 2,200, while approximately 1.6 million houses were damaged or destroyed, leaving an estimated 14 million people without homes. Pakistan Floods of 2010

13. Urbanization and Land Use Change Deforestation . Climate Change Heavy Rainfall: One of the most common causes of flooding is heavy or prolonged rainfall. If the amount of rainfall exceeds the capacity of the soil to absorb water or the capacity of rivers and drainage systems to carry it away, flooding can occur. Flash Floods: Flash floods are sudden and intense floods that can occur within minutes or hours of heavy rainfall. They are common in steep terrains or areas with poor drainage. Dam or Levee Failures: Infrastructure such as dams and levees are built to control water flow and prevent flooding. However, failure or breach of these structures can lead to catastrophic flooding downstream .

14. Thank You