Answer:

1. Earthquakes are natural phenomena that occur when there is a sudden release of energy in the Earth's crust, resulting in seismic waves. This release of energy is usually caused by the movement of tectonic plates, which make up the Earth's surface. The Earth's crust is divided into several large and small plates that constantly interact with each other. When these plates move, they can get locked due to friction, and when the stress on the locked portion exceeds the strength of the rocks, it causes a sudden slip, resulting in an earthquake.

2. Volcanoes are openings or vents in the Earth's crust through which molten rock, gases, and other materials erupt onto the surface. They are typically found near tectonic plate boundaries, where there is a convergence or divergence of plates. Volcanic eruptions occur when there is an accumulation of magma (molten rock) beneath the Earth's surface, which rises to the surface due to various factors such as increased pressure, gas expansion, or a decrease in the surrounding rock's strength. The eruption can release lava, ash, gases, and pyroclastic materials into the atmosphere or form volcanic cones and lava flows.

3. Earthquakes and volcanic eruptions have significant effects on the structure of the Earth's surface. Earthquakes can cause ground shaking, which can lead to the formation of faults, fractures, and landslides. They can also generate tsunamis if they occur underwater. Volcanic eruptions can result in the formation of new land through lava flows and the deposition of volcanic materials. Over time, repeated volcanic eruptions can build up volcanic cones and create new landforms.

4. When it comes to earthquake preparedness, it is important to take certain actions before, during, and after an earthquake to ensure safety:

- BEFORE an earthquake: Prepare an emergency kit with essential supplies, create an emergency plan for your family or household, and secure heavy furniture and objects that could potentially cause harm during shaking.

- DURING an earthquake: Drop to the ground, take cover under a sturdy piece of furniture, and hold on until the shaking stops. Avoid windows, heavy objects, and tall furniture that may topple. If outside, move to an open area away from buildings, trees, and utility wires.

- AFTER an earthquake: Check for injuries and provide first aid if needed. Assess your surroundings for hazards, such as gas leaks or damaged structures, and evacuate if necessary. Listen to local authorities for instructions and be prepared for aftershocks, which are smaller earthquakes that may occur after the main event.