What are earthquakes?

An earthquake is a phenomenon that arises when rocks deep within the Earth's crust suddenly shift, causing abrupt shocks or a series of them. These seismic occurrences come about due to the release of built-up pressure resulting from the movement of tectonic plates and can manifest at various plate boundaries.

When the Earth's crustal plates encounter resistance and become immobilized, pressure and tension gradually accumulate over time. Eventually, this amassed pressure is discharged, resulting in the release of an immense amount of energy in the form of seismic waves. These waves then propagate through the crust, giving rise to ground shaking, at times with substantial intensity. The magnitude of an earthquake serves as an indicator of the true potency of these seismic waves.

The point of origin for an earthquake within the crust is known as the focus, which is typically located several miles beneath the surface. Directly above the focus lies the epicenter, the area experiencing the most severe effects of the earthquake.

Within the Caribbean region, most Commonwealth countries find themselves situated near plate boundaries, except for the Bahamas and Guyana. The Caribbean plate moves eastward relative to its neighboring North America and South America plates, with a rate of approximately 20 millimeters (¾ inch) per year. This movement generates a moderate level of activity at the plate boundaries.

More specifically, earthquakes occur along the northern edge of the Caribbean plate, encompassing areas near Jamaica and the Virgin Islands. These earthquakes, classified as intraplate earthquakes, arise from internal deformation within a specific section of the North America plate. They tend to cluster at depths of up to 200 kilometers (125 miles).

The effects brought about by an earthquake pertain to the resultant damage caused by the seismic event. These effects can vary based on several factors. The magnitude of the earthquake, measured on the Richter scale, determines its potential for destruction, with higher magnitudes indicating greater damage. The level of development in the affected area also plays a role, as more affluent nations are often better equipped to anticipate, safeguard, and respond to earthquake consequences. Furthermore, the depth of the earthquake's focus and the distance from the epicenter influence the severity of the impact. Additional factors include population density, as densely populated regions face a heightened risk of casualties, as well as the time of day when the earthquake strikes.

Mitigation strategies aim to prevent or minimize the risks posed by earthquakes to human life, property, societal and economic activities, and natural resources. It is crucial to note that earthquakes themselves do not directly cause harm to individuals. Rather, it is the collapse or damage of buildings and infrastructure that leads to injuries and fatalities. Hence, the primary emphasis of earthquake mitigation efforts should be on fortifying buildings and infrastructure.

Before an earthquake occurs, a range of measures can be implemented to prepare for and mitigate potential damage. These measures encompass the development of action plans to aid affected individuals at both governmental and individual levels.

At the governmental level, the following measures can be undertaken:

• Conducting surveys and assessments to identify affected areas, particularly those heavily impacted.
• Prioritizing the dispatch of first responders to the most severely affected regions.
• Promptly restoring utilities and infrastructure.
• Promptly seeking regional and international assistance, if necessary.
• Distributing relief supplies to areas in need.
• Timely dissemination of announcements to keep the population informed about impacted areas and where to obtain emergency supplies.

At the individual level, the following steps can be taken:

• Checking for injuries and providing essential first aid.
• Ensuring personal safety by inspecting for gas leaks, water and sewage breaks, and downed power lines, and promptly turning off relevant utilities.
• Assessing building damage and making preparations for potential issues during aftershocks.
• Reporting hazards such as broken water lines or fallen electrical poles to the appropriate authorities.
• Dealing with hazardous spills appropriately.
• Being prepared for aftershocks.
• Remaining tuned to the radio for instructions from public safety agencies.
• Restricting telephone usage to emergency purposes only.
• Avoiding any unauthorized forays into the neighborhood or areas without proper authorization or safety precautions.

Josiah Renne (PC)