It is the shaking of the earth. It is caused due the release of energy, which generates waves that travel in all directions.  Mass movement— Surface displacement of earthen materials due to ground shaking triggered by earthquakes.

Nearly 59% of India’s territory is prone to moderate to severe earthquakes.

11% fall in very high-risk zone V.

Seven states in North East, Andaman & Nicobar Islands and part of Eight states/UT (Bihar, Gujarat, HP, Uttarakhand, J&K, Ladakh, Punjab and WB) are in Seismic Zone V i.e., prone to very high damage risk.

Nodal Ministry: Min. of Earth Sciences (MOES).

Types of Earthquakes:

1. Tectonic Earthquakes: Subtypes include transform, divergent, and convergent plate boundary earthquakes.
2. Volcanic Earthquakes: these earthquakes occur as magma moves beneath the Earth’s surface.
3. Induced Earthquakes: Triggered by human activities such as mining, reservoir-induced seismicity, and hydraulic fracturing (fracking).

Types of Mass Movements:

1. Landslides: Rapid downslope movement of rock, soil, and debris. Subtypes include rockfalls, debris flows, and mudslides.
2. Avalanches: Rapid downhill movement of snow, ice, and debris. It can be triggered by various factors, including snow instability.
3. Creep: Slow, continuous movement of soil or rock downslope over time.
4. Solifluction: This type of creep occurs in areas with permanently frozen ground (permafrost).

Criteria to declare:

The declaration of an earthquake usually involves various stages and considerations:

1. Seismic Event Detection: First detected by a network of seismometers and seismic monitoring agencies. In India, the Indian Meteorological Department (IMD) is responsible for monitoring and detecting seismic activity.
2. Magnitude Threshold: Seismic events below a certain magnitude may not trigger official declarations. The specific magnitude threshold may vary depending on the region and local policies.
3. Intensity Assessment: The Modified Mercalli Intensity (MMI) & Ritcher scale is often used to evaluate the impact of the earthquake on the ground.
4. Post–Event Assessment: to evaluate the extent of damage, the needs of affected communities, and the effectiveness of the response efforts.

Causes:

• Natural:
  1. Tectonic movements: Sudden tectonic movements within the Earth’s crust resulting in the release of energy along a fault. Rocks along a fault tend to move in opposite directions (divergent plate boundary). This causes a release of energy, and the energy waves travel in all directions.  EQ may also occur in transform boundaries where (Plates slide past each other) and Subduction Zones.
  2. Volcanic activities: The movement of magma and the release of gases can induce volcanic earthquakes.
  3. Landslides and avalanches.
• Anthropogenic:
  1. Dams: The filling of large reservoirs behind dams can increase pressure on underlying faults, triggering earthquakes.
  2. Underground Nuclear tests
  3. Geothermal Energy Extraction: The extraction of geothermal fluids from the Earth’s crust can lead to induced seismicity by altering subsurface pressures and permeability.
  4. Hydraulic Fracturing (Fracking): injecting fluids into the ground at high pressure to extract oil and gas can induce seismic events by altering subsurface pressure and lubricating fault lines.
  5. Mining: Underground mining operations can induce seismic events when rock masses are destabilized.

Mitigation:

1. Building Codes: Enforce strict construction codes (National building code 2016 guidelines) that ensure buildings and infrastructure can withstand seismic forces.
2. Retrofitting: Upgrade older buildings to meet current seismic standards.
3. Early Warning Systems: Implement earthquake early warning systems to provide advance notice to residents and businesses.
4. Emergency Preparedness: Educate the public on earthquake preparedness, including creating emergency kits and evacuation plans.
5. Land Use Planning: Restrict development in high-risk areas and consider seismic hazards in urban planning.
6. Insurance: Encourage earthquake insurance to help with recovery efforts.
7. Seismic Hazard Assessment: Continuously monitor and assess seismic activity to refine risk assessments.
8. Public Education: Raise awareness about earthquake risks and safety measures through campaigns and drills.
9. Critical Infrastructure Resilience: Strengthen essential infrastructure like hospitals, bridges, and power plants.
10. International Cooperation: Collaborate with neighboring regions to share knowledge and resources for disaster response and recovery.

NDMA Guidelines:

Six pillars of earthquake management in India:

1. Ensure the incorporation of earthquake resistant design features for the construction of new structures.
2. Facilitate selective strengthening and seismic retrofitting of existing priority and life line structures In earthquake prone areas.
3. Improve the compliance regime through appropriate regulation and enforcement.
4. Improve the awareness and preparedness of all stakeholders.
5. Introduce appropriate capacity development interventions for effective earthquake management (including education, training, documentation, R&D)
6. Strengthen the emergency response capability in earthquake prone areas.

Best Practices:

Agriculture fair Satara Maharashtra– demonstration of the earthquake resistant construction structures in annual fairs, which are also cost-effective.
Japan-urgent earthquake detection and alarm system to shut off electricity supply.
Traditional Dhajji–Dewari system of building houses in Kashmir.

Way Forward:

• Governments and policymakers ought to know better than act in a piecemeal manner.
• Programmes like the ongoing Urban 20 meetings are an excellent opportunity for international knowledge exchange on earthquake preparedness.
• The Delhi High Court’s directions must act as a reminder for the inclusion of an earthquake preparedness policy in urban renewal programmes such as the Smart Cities Mission.
• A policy on earthquake preparedness requires a visionary, radical and transformative approach.