Mohorovičić discontinuity - wikipedia Mohorovičić discontinuity World map showing the depth of the Moho. The Mohorovičić discontinuity ( Croatian pronunciation : ( moxorôʋiːt͡ʃit͡ɕ ) ), usually referred to as the Moho, is the boundary between the Earth 's crust and the mantle. Named after the pioneering Croatian seismologist Andrija Mohorovičić, the Moho separates both the oceanic crust and continental crust from underlying mantle. The Moho lies almost entirely within the lithosphere ; only beneath mid-ocean ridges does it define the lithosphere -- asthenosphere boundary. The Mohorovičić discontinuity was first identified in 1909 by Mohorovičić, when he observed that seismograms from shallow - focus earthquakes had two sets of P - waves and S - waves, one that followed a direct path near the Earth 's surface and the other refracted by a high - velocity medium. The Mohorovičić discontinuity is 5 to 10 kilometres ( 3 -- 6 mi ) below the ocean floor, and 20 to 90 kilometres ( 10 -- 60 mi ) beneath typical continental crusts, with an average of 35 kilometres ( 22 mi ). Contents 1 Nature 2 Exploration 3 See also 4 Notes 5 References 6 External links Nature Earth cross-section showing location of the Mohorovičić discontinuity ( labelled as 2 ) Two paths of a P - wave, one direct and one refracted as it crosses the Moho. Ordovician ophiolite in Gros Morne National Park, Newfoundland. This rock which formed the Ordovician Moho is exposed on the surface. Immediately above the Moho, the velocities of primary seismic waves ( P - waves ) are consistent with those through basalt ( 6.7 -- 7.2 km / s ), and below they are similar to those through peridotite or dunite ( 7.6 -- 8.6 km / s ). That suggests the Moho marks a change of composition, but the interface appears to be too even for any believable sorting mechanism within the Earth. Near - surface observations suggest such sorting produces an irregular surface. The Moho is characterized by a transition zone of up to 500 m thick. Ancient Moho zones are exposed above - ground in numerous ophiolites around the world. Exploration During the late 1950s and early 1960s the executive committee of the U.S. National Science Foundation funded drilling a hole through the ocean floor to reach this boundary. However the operation, named Project Mohole, never received sufficient support and was mismanaged ; the United States Congress canceled it in 1967. Soviet scientists at the Kola Institute pursued the goal simultaneously ; after 15 years they reached a depth of 12,260 metres ( 40,220 ft ), the world 's deepest hole, before abandoning their attempt in 1989. Reaching the discontinuity remains an important scientific objective. One proposal considers a rock - melting radionuclide - powered capsule with a heavy tungsten needle that can propel itself down to the Moho discontinuity and explore Earth 's interior near it and in the upper mantle. The Japanese project Chikyu Hakken ( `` Earth Discovery '' ) also aims to explore in this general area with the drilling ship, Chikyū, built for the Integrated Ocean Drilling Program ( IODP ). Plans called for the drill - ship JOIDES Resolution to sail from Colombo in Sri Lanka in late 2015 and to head for the Atlantis Bank, a promising location in the southwestern Indian Ocean on the Southwest Indian Ridge, to attempt to drill an initial bore hole to a depth of approximately 1.5 kilometres. The attempt did not even reach 1.3 km, but researchers hope to further their investigations at a later date. See also Brittle -- ductile transition zone Core -- mantle boundary Kola Superdeep Borehole Lehmann discontinuity Notes Jump up ^ Mangold, Max ( 2005 ). Aussprachewörterbuch ( in German ) ( 6th ed. ). Mannheim : Dudenverlag. p. 559. ISBN 9783411040667. ^ Jump up to : Andrew McLeish ( 1992 ). Geological science ( 2nd ed. ). Thomas Nelson & Sons. p. 122. ISBN 0 - 17 - 448221 - 3. Jump up ^ James Stewart Monroe ; Reed Wicander ( 2008 ). The changing Earth : exploring geology and evolution ( 5th ed. ). Cengage Learning. p. 216. ISBN 0 - 495 - 55480 - 4. Jump up ^ RB Cathcart & MM Ćirković ( 2006 ). Viorel Badescu ; Richard Brook Cathcart & Roelof D. Schuiling, eds. Macro-engineering : a challenge for the future. Springer. p. 169. ISBN 1 - 4020 - 3739 - 2. Jump up ^ Benjamin Franklin Howell ( 1990 ). An introduction to seismological research : history and development. Cambridge University Press. p. 77 ff. ISBN 0 - 521 - 38571 - 7. Jump up ^ D.P. McKenzie - The Mohorovičić Discontinuity Jump up ^ `` How the Soviets Drilled the Deepest Hole in the World ''. Wired. 2008 - 08 - 25. Retrieved 2008 - 08 - 26. Jump up ^ Ozhovan, M. ; F. Gibb ; P. Poluektov & E. Emets ( August 2005 ). `` Probing of the Interior Layers of the Earth with Self - Sinking Capsules ''. Atomic Energy. 99 ( 2 ) : 556 -- 562. doi : 10.1007 / s10512 - 005 - 0246 - y. Jump up ^ Witze, Alexandra ( December 2015 ). `` Quest to drill into Earth 's mantle restarts ''. Nature News. Jump up ^ Kavanagh, Lucas ( 2016 - 01 - 27 ). `` Looking Back on Expedition 360 ''. JOIDES Resolution. Retrieved 2016 - 09 - 21. We may not have made it to our goal of 1300 m, but we did drill the deepest ever single - leg hole into hard rock ( 789 m ), which is currently the 5th deepest ever drilled into the hard ocean crust. We also obtained both the longest ( 2.85 m ) and widest ( 18 cm ) single pieces of hard rock ever recovered by the International Ocean Discovery Program and its predecessors ! (... ) Our hopes are high to return to this site in the not too distant future. References Harris, P. ( 1972 ). `` The composition of the earth ''. In Gass, I.G. ; et al. Understanding the earth : a reader in the earth sciences. Horsham : Artemis Press for the Open University Press. ISBN 0 - 85141 - 308 - 0. `` Schlumberger Oilfield Glossary ''. Schlumberger. Retrieved 2008 - 07 - 17. Dixon, Dougal ( 2000 ). Beginner 's Guide to Geology. New York : Bounty Books. ISBN 0 - 7537 - 0358 - 0. External links Britt, Robert Roy ( 2005 - 04 - 07 ). `` Hole Drilled to Bottom of Earth 's Crust, Breakthrough to Mantle Looms ''. Imaginova. Retrieved 2008 - 07 - 17. `` Digging a Hole in the Ocean : Project Mohole, 1958 - 1966 ''. National Academy of Sciences. Retrieved 2008 - 07 - 17. Map of the Moho depth of the European plate Physical oceanography Waves Airy wave theory Ballantine scale Benjamin -- Feir instability Boussinesq approximation Breaking wave Clapotis Cnoidal wave Cross sea Dispersion Edge wave Equatorial waves Fetch Gravity wave Green 's law Infragravity wave Internal wave Iribarren number Kelvin wave Kinematic wave Longshore drift Luke 's variational principle Mild - slope equation Radiation stress Rogue wave Rossby wave Rossby - gravity waves Sea state Seiche Significant wave height Soliton Stokes boundary layer Stokes drift Stokes wave Swell Trochoidal wave Tsunami megatsunami Undertow Ursell number Wave action Wave base Wave height Wave power Wave radar Wave setup Wave shoaling Wave turbulence Wave -- current interaction Waves and shallow water one - dimensional Saint - Venant equations shallow water equations Wind wave model Circulation Atmospheric circulation Baroclinity Boundary current Coriolis force Coriolis -- Stokes force Craik -- Leibovich vortex force Downwelling Eddy Ekman layer Ekman spiral Ekman transport El Niño -- Southern Oscillation General circulation model Geostrophic current Global Ocean Data Analysis Project Gulf Stream Halothermal circulation Humboldt Current Hydrothermal circulation Langmuir circulation Longshore drift Loop Current Modular Ocean Model Ocean dynamics Ocean gyre Princeton Ocean Model Rip current Subsurface currents Sverdrup balance Thermohaline circulation shutdown Upwelling Whirlpool World Ocean Circulation Experiment Tides Amphidromic point Earth tide Head of tide Internal tide Lunitidal interval Perigean spring tide Rip tide Rule of twelfths Slack water Tidal bore Tidal force Tidal power Tidal race Tidal range Tidal resonance Tide gauge Tideline Landforms Abyssal fan Abyssal plain Atoll Bathymetric chart Coastal geography Cold seep Continental margin Continental rise Continental shelf Contourite Guyot Hydrography Oceanic basin Oceanic plateau Oceanic trench Passive margin Seabed Seamount Submarine canyon Submarine volcano Plate tectonics Convergent boundary Divergent boundary Fracture zone Hydrothermal vent Marine geology Mid-ocean ridge Mohorovičić discontinuity Vine -- Matthews -- Morley hypothesis Oceanic crust Outer trench swell Ridge push Seafloor spreading Slab pull Slab suction Slab window Subduction Transform fault Volcanic arc Ocean zones Benthic Deep ocean water Deep sea Littoral Mesopelagic Oceanic Pelagic Photic Surf Swash Sea level Deep - ocean Assessment and Reporting of Tsunamis Future sea level Global Sea Level Observing System North West Shelf Operational Oceanographic System Sea - level curve Sea level rise World Geodetic System Acoustics Deep scattering layer Hydroacoustics Ocean acoustic tomography Sofar bomb SOFAR channel Underwater acoustics Satellites Jason - 1 Jason - 2 ( Ocean Surface Topography Mission ) Jason - 3 Related Argo Benthic lander Color of water DSV Alvin Marginal sea Marine energy Marine pollution Mooring National Oceanographic Data Center Ocean Ocean exploration Ocean observations Ocean reanalysis Ocean surface topography Ocean thermal energy conversion Oceanography Pelagic sediment Sea surface microlayer Sea surface temperature Seawater Science On a Sphere Thermocline Underwater glider Water column World Ocean Atlas Commons Structure of the Earth Shells Crust Lithosphere Mesosphere Mantle Asthenosphere Lithospheric mantle Subcontinental lithospheric mantle Oceanic lithospheric mantle Outer core Inner core Discontinuities Conrad ( continental crust ) Mohorovičić ( crust -- mantle ) Lehmann ( upper mantle ) Gutenberg ( mantle -- core ) Lehmann ( core ) Arguments Plate tectonics Retrieved from `` https://en.wikipedia.org/w/index.php?title= Mohorovičić_discontinuity&oldid = 802574723 '' Categories : Plate tectonics Structure of the Earth Hidden categories : CS1 German - language sources ( de ) All articles with unsourced statements Articles with unsourced statements from April 2014 Talk Contents About Wikipedia Afrikaans Azərbaycanca Беларуская Български Bosanski Català Čeština Deutsch Eesti Ελληνικά Español Esperanto Euskara فارسی Français Gaeilge Galego 한국어 Հայերեն Hrvatski Bahasa Indonesia Italiano עברית ქართული Latina Lietuvių Bahasa Melayu Nederlands 日本 語 Norsk nynorsk Polski Português Русский Scots Slovenčina Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Svenska ไทย Türkçe Українська Tiếng Việt 中文 Edit links This page was last edited on 27 September 2017, at 01 : 42. 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Question: the boundary that separates the crust from the mantle is the
Answer: Mohorovičić discontinuity