ภัยธรรมชาติ

ภัยธรรมชาติ



ภัยธรรมชาติ คือผลกระทบที่เกิดจากอันตรายทางธรรมชาติ (เช่น ภูเขาไฟระเบิด, แผ่นดินไหว, หรือแผ่นดินถล่ม) ซึ่งทำให้เกิดผลกระทบต่อการดำรงชีวิตของมนุษย์ ภัยธรรมชาติมีหลายรูปแบบแตกต่างกันไปบางอย่างร้ายแรงน้อย บางอย่างร้ายแรงมากซึ่งอาจทำให้เกิดผลเสียต่อชีวิตและทรัพย์สิน เช่น อุทกภัย หรือน้ำท่วม การเกิดพายุ (วาตภัย) การเกิดแผ่นดินไหว ภูเขาไฟระเบิด
       
          A natural disaster is a major adverse event resulting from natural processes of the Earth; examples include floods, volcanic eruptions, earthquakes, tsunamis, and other geologic processes. A natural disaster can cause loss of life or property damage, and typically leaves some economic damage in its wake, the severity of which depends on the affected population's resilience, or ability to recover.^[1]
An adverse event will not rise to the level of a disaster if it occurs in an area without vulnerable population.^[2][3][4] In a vulnerable area, however, such as San Francisco, an earthquake can have disastrous consequences and leave lasting damage, requiring years to repair.
In 2012, there were 905 natural catastrophes worldwide, 93% of which were weather-related disasters. Overall costs were US$170 billion and insured losses $70 billion. 2012 was a moderate year. 45% were meteorological (storms), 36% were hydrological (floods), 12% were climatological (heat waves, cold waves, droughts, wildfires) and 7% were geophysical events (earthquakes and volcanic eruptions). Between 1980 and 2011 geophysical events accounted for 14% of all natural catastrophes.^[5]

Earthquakes

     earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. At the Earth's surface, earthquakes manifest themselves by vibration, shaking and sometimes displacement of the ground. The vibrations may vary in magnitude. Earthquakes are caused mostly by slippage within geological faults, but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests. The underground point of origin of the earthquake is called the focus. The point directly above the focus on the surface is called the epicenter. Earthquakes by themselves rarely kill people or wildlife. It is usually the secondary events that they trigger, such as building collapse, fires, tsunamis (seismic sea waves) and volcanoes, that are actually the human disaster. Many of these could possibly be avoided by better construction, safety systems, early warning and planning. Some of the most significant earthquakes in recent times include:

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• The 2004 Indian Ocean earthquake, the third largest earthquake recorded in history, registering a moment magnitude of 9.1-9.3. The huge tsunamis triggered by this earthquake killed at least 229,000 people.
• The 2011 Tōhoku earthquake and tsunami registered a moment magnitude of 9.0. The earthquake and tsunami killed 15,889 and injured 6,152. 2,609 were still missing as of 2014.
• The 8.8 magnitude February 27, 2010 Chile earthquake and tsunami cost 525 lives.^[7]
• The 7.9 magnitude May 12, 2008 Sichuan earthquake in Sichuan Province, China. Death toll at over 61,150 as of May 27, 2008.
• The 7.7 magnitude 2006 Pangandaran earthquake and tsunami.
• The 6.9 magnitude 2005 Azad Jammu & Kashmir and KPK province Earthquake, which killed or injured above 75,000 people in Pakistan.