Knowledge and understanding: Acquire the knowledge concerning the main geophysical methods for near surface exploration. Learn the basic information of acquisition, analysis and processing of the corresponding data. Applying knowledge and understanding: The knowledge that has been learnt allows to apply in various contexts the different methodologies studied, including analysis and processing of the geophysical data.
Expected learning outcomes
Making judgements: The student is able to evaluate autonomously the geophysical methodologies that can be applied for near surface exploration, knowing the advantages, the disadvantages and the limitations. He/Her knows the procedures to process the acquired geophysical data, and can formulate judgements on the correctness and accuracy of the steps applied. Communication skills: The student is able to clearly communicate to third party the topics of the near surface exploration, the problems to tackle and the possible solutions. He/her can easily interact with the experts in this field for what concerns the procedures for the acquisition, analysis and processing of the available data. Learning skills: Give the student the ability to learn autonomously topics that can not be dealt with during the lessons due to the limited time available, and also give him/her the ability to deepen the ones discussed.
Lesson period: Second semester
(In case of multiple editions, please check the period, as it may vary)
· Gravity surveying: Outlines of the Earth's gravity field and of the density of rocks; field measurement procedures and gravimetric corrections to estimate the Bouguer's anomaly for micro-gravity surveys; examples of anomalies. · Magnetic surveying: Outlines of the Earth's magnetic field and of the magnetic properties of minerals and rocks; measurement instruments and field measurement procedures; examples of anomalies. · Self-potential methods: basic physical principles; procedures of measurement and data acquisition. · Electrical surveying: Electrical conduction in rocks; Ohm's law, Archie's law; electrical field generated by a point electrode; electrical quadrupole and apparent resistivity; principal arrays. Vertical electrical soundings; constant separation traverse; electrical resistivity tomography (ERT). · Induced polarization method: basic physical principles; definition of polarization, apparent polarization and metal factor. · Seismic surveying: basic properties of body and surface waves; seismic wave velocities in rocks. Refraction seismic: traveltimes for horizontal and dipping layers; intercept times and plus-minus method (Generalized Reciprocal Methods). Reflection seismic: principles, acquisition, multifold coverage, building of a stack section. Multichannel analysis of surface waves (MASW) and Horizontal-to-vertical spectral ratio (HVSR): principles and measurement procedures. · Electromagnetic surveying: basic physical principles; basic characteristics of VLF, FDEM and TDEM methods. · Ground Penetrating Radar (GPR): the absolute and relative permittivity; reflection and transmission coefficient of electromagnetic waves; directivity function of receiving and transmitting antennas; the radargram.
For each survey method, examples of real-world applications will be shown and discussed.
Prerequisites for admission
Basic knowledge of physics
Lectures and demonstrations of data acquisition
1. Reynolds, J.M., 2011, An Introduction to Applied and Environmental Geophysics, Wiley. 2. Telford, W.M., Geldart, L.P., & Sherriff, R.E., 1990, Applied Geophysics, 2nd Ed, Cambridge University Press. 3 Loke, M.H., 2016, Tutorial : 2-D and 3-D electrical imaging surveys. Downloadable from http://www.geotomosoft.com/downloads.php