Heinrich Holland

There are peaks, valleys, jagged edges, rolling hills, and everything in between. In general, we call these geological features, but this term is very broad and refers to any of the physical features on Earth’s surface. You might also hear them referred to as landscapes, topography, and landforms.

Geological processes

• Erosion. Erosion involves the movement of rock fragments through gravity, wind, rain, rivers, oceans and glaciers.
• Landforms. Landforms are features on the Earth’s surface that make up the terrain.
• Weathering. Weathering is the wearing down or breaking of rocks while they are in place.
• Deposition.
• Relief.

Why Study Geology?

• Predicting the behavior of Earth systems and the universe.
• Finding adequate supplies of natural resources, such as ground water, petroleum, and metals.
• Conserving soils and maintaining agricultural productivity.
• Developing natural resources in ways that safeguard the environment.
• Maintaining quality of water supplies.

Geology looks at some of the most important issues in society today including energy sources and sustainability, climate change, the impacts of developments on the environment, water management, mineral resources and natural hazards.

Geologic Hazards

• Seismic hazards related to earthquakes, including ground ru​​pture/fault​ing​, liquefaction​, strong motion, and tsunami.
• Landslides​ of all kinds, including seismically-triggered landslides, debris flows, mud flows, and rock falls.
• Mineral ​hazards such as asbestos, radon, and mercury.

Geohazards

• Earthquakes – Liquefaction (soils), Tsunamis.
• Volcanic Eruptions – Lava Flows, Ash Fall, Lahars.
• Landslides – Rock Falls or Slides, Debris Flows, Mud Flows.
• Floods – Inundation, Erosion.
• Snow Avalanches.
• Sand Blasting (Windblown)

This zone of volcanism and earthquakes, involving several plates and trenches and manifested in Latin America by the Andes Mountains and their extension into Central America and Mexico, virtually encircles the Pacific Ocean and is known as the “Ring of Fire.” Geologic hazards-earthquakes, the landslides they induce.

Geologic mapping is vitally important to education, science, business and a wide variety of public policy concerns. For example, geologic maps help us assess the likelihood, prepare for, and minimize damage from natural hazards. Geologic maps identify fault zones, some of which are still active and cause earthquakes.

Geohazards such as earthquakes and volcanoes would not happen if the Earth’s crust was solid and did not move. The theory of continental drift explains how the continents have moved over time due to plate tectonics. We would not have geohazards if the Earth’s crust was solid and did not move.

Sinkholes are usually caused by a geologic feature known as karst topography. Karst can form where the underlying bedrock is composed of material that can be slowly dissolved by water. There are a few conditions that increase the hazards associated with sinkholes.

Sinkholes are defined as a depression or hole in the surface of the earth due to the erosion of the underlying ground layer. Such sinkholes develop over time with a diameter ranging between 1 – 600m. Sinkholes can form on both land masses and ocean ground surfaces.

Sinkholes are common where the rock below the land surface is limestone or other carbonate rock, salt beds, or in other soluble rocks, such as gypsum, that can be dissolved naturally by circulating ground water. Sinkholes also occur in sandstone and quartzite terrains.