In January 2009 a geophysical survey was undertaken by a joint team representing Archaeological Prospection Services of Southampton and The British School at Rome. This survey was carried out at the request of Prof Andrew Wallace-Hadrill, Director of The Herculaneum Conservation Project and The British School at Rome. The purpose of the project was to aid in the identification of the paths of the tunnels which were dug in the 18th century in the area of the Basilica Noniana. Survey was undertaken using both ground penetrating radar (GPR) and electrical resistivity tomography (ERT), two techniques which can obtain data at greater depths than some other techniques, which was especially important considering the tremendous depth of deposit in this area. The application of both GPR and ERT on this survey proved invaluable, as the two techniques complimented each other to provide a more complete identification of the tunnels and structures that lay beneath the surface. In the area of the basilica the ERT results were able to identify the course of the 18th Century tunnels, while the GPR results were more successful in identifying a series of standing structures in this zone. Both techniques were void of any significant anomalies to the north of the basilica, adding some weight to the suggestion that this may have been the area of the forum of _Herculaneum_.