Environmental Geophysics: Remote Sensing and Imaging

Environmental Geophysics: Remote Sensing and Imaging

Introduction:
Environmental geophysics is a branch of geology that applies physical principles to the study of the environment. Remote sensing and imaging are two important techniques that have significantly improved the understanding of the earth’s surface and subsurface.

Key Concepts:

1. Remote sensing: It is the process of gathering information about the environment without physically being present. The equipment used for remote sensing includes satellites, drones, and airplanes, which capture data in the form of images, videos, and other digital formats.

2. Imaging: A technique that uses different wavelengths of electromagnetic radiation to create images of the subsurface. These images can help geologists identify the layers of the earth, the location of natural resources, and the presence of contaminants.

3. Geophysical methods: Remote sensing and imaging are just two of the many geophysical methods used in environmental geophysics. Other methods include gravity surveys, magnetic surveys, and seismic surveys.

Relevant Equations and Formulas:

1. Radiometric calibration: A technique used to convert the raw data from remote sensing equipment into meaningful information. The formula for radiometric calibration is:

Digital number = (radiance x gain) + offset

2. Spectral signature: The unique pattern of reflectance of an object at different wavelengths of electromagnetic radiation. The formula for spectral signature is:

Reflectance = Rλ / Esλ

Examples:

1. Airborne magnetic surveys: These surveys are used to map the distribution of magnetic minerals in the earth’s crust. By analyzing the data collected from these surveys, geologists can identify the location of mineral deposits and geological structures.

2. Ground-penetrating radar: A form of imaging that uses high-frequency electromagnetic radiation to create images of the subsurface. This technique is commonly used to locate buried objects, such as pipes, cables, and archaeological artifacts.

References for Further Learning:

1. Kearey, P., & Brooks, M. (2002). An introduction to geophysical exploration. John Wiley & Sons.

2. Milsom, J. (2011). Field Geophysics. John Wiley & Sons.

3. Lillesand, T. M., Kiefer, R. W., & Chipman, J. W. (2015). Remote sensing and image interpretation. John Wiley & Sons.

Conclusion:
Remote sensing and imaging are important techniques used in environmental geophysics to gather information about the subsurface without physically being there. By analyzing the data collected from these techniques, geologists can identify the location of natural resources, geological structures, and contaminants.