Abstract
The analysis of teleseismic travel time residuals observed on the Larderello seismic network has revealed a sharp low velocity zone in the center of the geothermal production area. Residuals from 101 teleseismic events, automatically determined with the implementation of a simulated annealing optimization procedure, are inverted to produce an image of an anomalous zone interpreted to be a series of intrusive bodies. The top of this zone is constrained to be below 6 km depth from local earthquake seismicity patterns and extends to a depth of greater than 20 km. The zone extends into the upper mantle and broadens with increasing depth. The observed travel time residual anomaly corresponds with observed gravity lows, high heat flow, the shallowing of a dominant upper-crustal reflection, and diminished teleseismic P-wave amplitudes. This body has elevated the temperatures in the region to over 350 °C at 2 km and is the origin of the geothermal energy.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
Achauer U, Greene L, Evans JR, Iyer HM (1986) Nature of the magma chamber underlying the Mono Craters area, eastern California, as determined from teleseismic travel time residuals. J Geophys Res 91:13873–13891.
Aki K, Christoffersson A, Husebye ES (1977) Determination of the three-dimensional seismic structure of the lithosphere. J Geophys Res 82:237–296.
Batini F, Nicolich R (1984) The application of seismic reflection methods to geothermal exploration. Seminar on Utilization of geothermal energy for electric power production and space heating. Florence, 11–17 May.
Batini F, Burgassi PD, Cameli GM, Nicolich R, Squarci P (1978) Contribution to the study of the deep lithospheric profiles: deep reflecting horizons in Larderello-Travale geothermal field. Mem Soc Geol Ital 9:477–484.
Batini F, Console R, Luongo G (1985) Seismological study of Larderello-Travale geothermal area. Geothermics 14:255–272.
Boccaletti M, Coli M, Eva C et al. (1983) Considerations on the seismotectonics of the northern Apennines. Tectonophysics 47:7–38.
Cataldi R, Lazzarotto A, Muffler LPJ, Squarci P, Stefani GC (1978) Assessment of geothermal potential of central and southern Tuscany. Geothermics 7:91–131.
Davis JC (1973) Statistics and data analysis in geology. Wiley, San Francisco, 550 pp.
Ellsworth WL (1977) Three dimensional structure of the crust and upper mantle beneath the island of Hawaii. PhD thesis, Massachusetts Inst Tech, 377 pp.
Giese P, Morelli C, Nicolich R, Wigger P (1981) Seismische Studien zur Bestimmung der Krustenstruktur im Bereich der geothermischen Anomalie der Toskana. Comm Eur Commun EUR 75–78 de MF.
Hayakawa M (1957) Prospecting of the underground structure at “Showa-Shinzan” by various geophysical methods, particularly seismic survey. JPN J Geophys 1:13–20.
Herrin E (1968) Seismological tables of P-phases. Bull Seismol Soc Am 58:1193–1241.
Iyer HM (1984) Geophysical evidence for the locations, shapes and sizes and internal structures of magma chambers beneath region of Quaternary volcanism. Phil Trans R Soc Lond Ser A, 310:473–510.
Iyer HM (1988) Seismological detection and delineation of magma chambers beneath interplate volcanic centers in western USA. In: King C, Scarpa R (eds) Modeling of volcanic processes. Vieweg, New York.
Iyer HM, Oppenheimer DH, Hitchcock T, Roloff LN, Caokley JM (1981) Large teleseismic P-wave delays in the Geysers Clear Lake geothermal region. US Geol Surv Prof Pap 1141:97–116.
Kirkpatrick S, Gelatt C, Vecchi M (1983) Optimization by simulated annealing. Sience220:671–680.
Murase T, McBirney AR (1973) Properties of some common igneous rocks and their melts at high temperatures. Geol Soc Am Bull 84:3563–3592.
Oppenheimer DH, Herkenhoff KE (1981) Velocity-density properties of the lithosphere from three-dimensional modeling at the Geysers-Clear Lake region, California. J Geophys Res 86:6057–6065.
Puxeddu M (1984) Structure and late Cenozoic evolution of the upper lithosphere in southwest Tuscany (Italy). Tectonophysics 101:357–382.
Rothman D (1986) Automatic estimation of large residual statics corrections. Geophysics51:332–346.
Sanders CO (1984) Location and configuration of magma bodies beneath Long Valley California, determined from anomalous Earthquake signals. J Geophys Res 89:8287–8302.
Steeples DW, Iyer HM (1976) Low velocity zone under Long Valley as determined from teleseismic events. J Geophys Res 81:849–860.
Taylor SR, Toksoz MN (1979) Three dimension crust and upper mantle structure of the northeastern United States. J Geophys Res 84:7627–7644.
Thompson CJ, Gubbins D (1982) Three-dimensional lithospheric modeling at NORSAR: linerarity of the method and amplitude variations from the anomalies. Geophys J R Astr Soc 71:1–36.
Zandt G (1978) Study of the three dimensional heterogeneity beneath seismic arrays in central California and Yellowstone, Wyoming. PhD Thesis, Massachusetts Inst Tech, USA.
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1992 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Foley, J.E., Toksoz, M.N., Batini, F. (1992). Three-Dimensional Inversion of Teleseismic Travel Time Residuals for Crust and Upper Mantle Velocity Structure in the Larderello Geothermal Field, Italy. In: Gasparini, P., Scarpa, R., Aki, K. (eds) Volcanic Seismology. IAVCEI Proceedings in Volcanology, vol 3. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-77008-1_24
Download citation
DOI: https://doi.org/10.1007/978-3-642-77008-1_24
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-77010-4
Online ISBN: 978-3-642-77008-1
eBook Packages: Springer Book Archive