The word "tomography" would be used here for traveltime or phase inversion, while the word "inversion" would be supposed to be related to waveform or wavefield inversion. Consequently, traveltime or delayed traveltime is the observable to be used in this seismic imaging workflow.

The methodology, named ray tomography, is based on ray tracing between each quake and related receivers where signals have been recorded

The picking observable is the first-arrival date either for P or for S phases. If enough recorded seismograms, one can deduce the quake location and its orign date, allowing to estimate the traveltime between the source and the receiver. From these traveltimes, one can deduce the velocity along the zone between the source and the receiver.

In fact, both hypocenter parameters and velocity parameters are inverted simultaneously.

Application to Corinth Gulf (Diana Latorre’s PhD)

• Seismic network and earthquake activity

  

• Team for network installation

  

• Seismic Vp velocity imaging through delayed traveltime tomography

  

• Seismic Vp/Vs ratio imaging

  

• Tentative interpretation of seismic images

  

Application to volcanic structures nearby Naples: Campi Flegrei & Mt Vesuvius

(work done by Tiziana Vanorio during her post-doc at GéoAzur)

• Team at rest at the top of Mt Vesuvius

  

• 3D ray tracing from quakes to stations at Campi Flegrei

  

• Vp velocity imaging along two vertical cross-sections

  

• Vs velocity imaging along two vertical cross-sections

  

Application to Western Alps (work in progress)