Abnormal Earthquake Behavior in the Velocity Zones Beneath Italy




Raines, Laura

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This project focuses on pre-processed seismic tomography and earthquake data from Italy. This data comes from the IRIS (Incorporated Research Institutions for Seismology) website, which provides seismic Earth models from other studies. The seismic Earth model for Italy shows two zones that are interesting; one zone has a high seismic velocity (HVZ), whereas the other has a low seismic velocity (LVZ). In addition, earthquake data shows that earthquakes do not occur in the high-velocity zone. The study, therefore, focuses on three main questions: Why is the LVZ where it is? Why is the HVZ where it is? Why do earthquakes not appear in the HVZ? Low-velocity zones could be caused by rifting creating significantly slower crust due to the melting of the rocks. Although there are earthquakes occurring prominently through sections of the LVZ, there are very few events in the HVZ. What’s more puzzling about this area is that the earthquakes continue above and below the HVZ. The nearly straight angle of the subduction zone could be responsible for changes in the HVZ that stop the earthquakes. It is also possible that the rocks in the HVZ behave differently than those in other areas due to layers of salt from the Mediterranean Basin, or it could be due to the release of volatiles along the subduction plate. To answer the above-stated questions I will search for other datasets to compare to the Earth model to determine the origin of the HVZ and LVZ and the disappearance of earthquakes in the HVZ.



Tomography, S-waves, Earthquakes, Italy, Sardinia, Sicily