{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:01:29Z","timestamp":1760230889263,"version":"build-2065373602"},"reference-count":53,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2022,8,12]],"date-time":"2022-08-12T00:00:00Z","timestamp":1660262400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"Basic Science Research Program through the National Research Foundation of Korea (NRF)","doi-asserted-by":"publisher","award":["NRF-2019R1I1A3A01063976"],"award-info":[{"award-number":["NRF-2019R1I1A3A01063976"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Chungnam National University","award":["NRF-2019R1I1A3A01063976"],"award-info":[{"award-number":["NRF-2019R1I1A3A01063976"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>In the future, when humans build their bases on terrestrial planets and their moons, caves will be the safest place for inhabitation. Large holes, believed to be cave entrances, have been discovered on the Moon, along with small features called \u201cimpact melt pits.\u201d In the Gravity Recovery and Interior Laboratory (GRAIL) gravity model, which is expressed in spherical harmonics (SH), it is difficult to express the gravity anomaly created by a small empty space below the surface. Nevertheless, we propose that a cave network, akin to an anthill, exists under the impact melt pits discovered on the Moon. This is because we think it is natural to apply a network created by Earth\u2019s small caves to the Moon. We obtained accurate Bouguer gravity measurements by calculating regional crustal density using localized admittance of the study area and detected weak gravity (mass deficit) information. By increasing the degrees and order of SH at regular intervals, we estimated the change in gravity at a specific position at high degrees and order, thereby extracting shallow depth information. To validate our method, we compared our results with those of existing studies that analyzed the previously known Marius Hills Hole (MHH) area. The analysis of seven regions in our study area revealed a mass deficit in some impact melt pits in four lunar regions (Copernicus, King, Stevinus, and Tycho). We propose that there is a cave network in this region, indicated by the gravitation reduction in the impact melt pits region. Our results can be useful for the selection of landing sites for future in situ explorations of lunar caves.<\/jats:p>","DOI":"10.3390\/rs14163926","type":"journal-article","created":{"date-parts":[[2022,8,15]],"date-time":"2022-08-15T23:44:03Z","timestamp":1660607043000},"page":"3926","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Plausible Detection of Feasible Cave Networks Beneath Impact Melt Pits on the Moon Using the Grail Mission"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4529-8002","authenticated-orcid":false,"given":"Ik-Seon","family":"Hong","sequence":"first","affiliation":[{"name":"Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon 34134, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9348-454X","authenticated-orcid":false,"given":"Yu","family":"Yi","sequence":"additional","affiliation":[{"name":"Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon 34134, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1038\/s41550-020-1200-6","article-title":"Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data","volume":"5","author":"Lauro","year":"2021","journal-title":"Nat. Astron."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"568","DOI":"10.1126\/science.1178658","article-title":"Character and Spatial Distribution of OH\/H2O on the Surface of the Moon Seen by M3 on Chandrayaan-1","volume":"326","author":"Pieters","year":"2009","journal-title":"Science"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1007\/BF00562463","article-title":"Lunar rilles and Hawaiian volcanic features: Possible analogues","volume":"3","author":"Cruikshank","year":"1972","journal-title":"Moon"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"289","DOI":"10.1007\/BF00561842","article-title":"Lava tubes and channels in the lunar Marius Hills","volume":"3","author":"Greeley","year":"1971","journal-title":"Moon"},{"key":"ref_5","first-page":"75","article-title":"On the Origin of Lunar Sinuous Rilles","volume":"1","author":"Oberbeck","year":"1969","journal-title":"Mod. Geol."},{"key":"ref_6","unstructured":"Mendell, W.W., Alred, J.W., Bell, L.S., Cintala, M.J., Crabb, T.M., Durrett, R.H., Finney, B.R., Franklin, H.A., French, J.R., and Greenberg, J.S. (1988, January 5\u20138). A Search for Intact Lava Tubes on the Moon: Possible Lunar Base Habitats. Proceedings of the Second Conference on Lunar Bases and Space Activities of the 21st Century, Houston, TX, USA."},{"key":"ref_7","unstructured":"Mendell, W.W. (1985). Lava tubes\u2014Potential shelters for habitats. Lunar Bases and Space Activities of the 21st Century, Lunar and Planetary Institute."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"E12","DOI":"10.1029\/2011JE003987","article-title":"Lunar equatorial surface temperatures and regolith properties from the Diviner Lunar Radiometer Experiment","volume":"117","author":"Vasavada","year":"2012","journal-title":"J. Geophys. Res. E Planets"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"121","DOI":"10.5140\/JASS.2015.32.2.121","article-title":"Detection of an impact flash candidate on the moon with an educational telescope system","volume":"32","author":"Kim","year":"2015","journal-title":"J. Astron. Space Sci."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Haruyama, J., Morota, T., Kobayashi, S., Sawai, S., Lucey, P.G., Shirao, M., and Nishino, M.N. (2012). Lunar Holes and Lava Tubes as Resources for Lunar Science and Exploration. Moon, Springer.","DOI":"10.1007\/978-3-642-27969-0_6"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"S41","DOI":"10.1269\/jrr.43.S41","article-title":"Lunar lava tube radiation safety analysis","volume":"43","author":"Angelis","year":"2002","journal-title":"J. Radiat. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1007\/s11038-010-9365-0","article-title":"Lunar dust: The Hazard and Astronaut Exposure Risks","volume":"107","author":"Cain","year":"2010","journal-title":"Earth Moon Planets"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/j.asr.2005.04.048","article-title":"A dynamic fountain model for lunar dust","volume":"37","author":"Stubbs","year":"2006","journal-title":"Adv. Space Res."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.icarus.2014.04.002","article-title":"Distribution, formation mechanisms, and significance of lunar pits","volume":"237","author":"Wagner","year":"2014","journal-title":"Icarus"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1029\/2007GL030709","article-title":"THEMIS observes possible cave skylights on Mars","volume":"34","author":"Cushing","year":"2007","journal-title":"Geophys. Res. Lett."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"33","DOI":"10.4311\/2010EX0167R","article-title":"Candidate cave entrances on Mars","volume":"74","author":"Cushing","year":"2012","journal-title":"J. Cave Karst Stud."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"141","DOI":"10.5140\/JASS.2014.31.2.141","article-title":"Identification of Martian Cave Skylights Using the Temperature Change during Day and Night","volume":"31","author":"Jung","year":"2014","journal-title":"J. Astron. Space Sci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1029\/2009GL040635","article-title":"Possible lunar lava tube skylight observed by SELENE cameras","volume":"36","author":"Haruyama","year":"2009","journal-title":"Geophys. Res. Lett."},{"key":"ref_19","unstructured":"Haruyama, J., Hara, S., Hioki, K., Morota, T., Yokota, Y., Shirao, M., Hiesinger, H., van der Bogert, C.H., Miyamoto, H., and Iwasaki, A. (2010, January 1\u20135). New Discoveries of Lunar Holes in Mare Tranquillitatis and Mare Ingenii. Proceedings of the 41st Lunar and Planetary Science Conference, The Woodlands, TX, USA."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.pss.2012.05.008","article-title":"Confirmation of sublunarean voids and thin layering in mare deposits","volume":"69","author":"Robinson","year":"2012","journal-title":"Planet. Space Sci."},{"key":"ref_21","unstructured":"Wagner, R.V., and Robinson, M.S. (2021, January 15\u201319). Occurrence and origin of lunar pits: Observations from a new catalog. Proceedings of the 52nd Lunar and Planetary Science Conference 2021, Virtual."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1007\/s11214-012-9952-7","article-title":"Gravity Recovery and Interior Laboratory (GRAIL): Mapping the lunar interior from crust to core","volume":"178","author":"Zuber","year":"2013","journal-title":"Space Sci. Rev."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"668","DOI":"10.1126\/science.1231507","article-title":"Gravity field of the moon from the Gravity Recovery and Interior Laboratory (GRAIL) mission","volume":"339","author":"Zuber","year":"2013","journal-title":"Science"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.icarus.2016.10.008","article-title":"The structural stability of lunar lava tubes","volume":"282","author":"Blair","year":"2017","journal-title":"Icarus"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"113442","DOI":"10.1016\/j.icarus.2019.113442","article-title":"Lunar lava tubes: Morphology to structural stability","volume":"338","author":"Theinat","year":"2020","journal-title":"Icarus"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1002\/2016GL071588","article-title":"Evidence of Large Empty Lava Tubes on the Moon using GRAIL Gravity","volume":"44","author":"Chappaz","year":"2017","journal-title":"Geophys. Res. Lett."},{"key":"ref_27","first-page":"1711","article-title":"Detection of Lunar Lava Tubes by Lunar Radar Sounder Onboard SELENE (Kaguya)","volume":"48","author":"Kaku","year":"2017","journal-title":"Geophys. Res. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"7395","DOI":"10.1109\/TGRS.2020.3033033","article-title":"Nadir Detection of Lunar Lava Tube by Kaguya Lunar Radar Sounder","volume":"59","author":"Kobayashi","year":"2021","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_29","unstructured":"Goossens, S., Lemoine, F.G., Sabaka, T.J., Nicholas, J.B., Mazarico, E., Rowlands, D.D., Loomis, B.D., Chinn, D.S., Neumann, G.A., and Smith, D.E. (2016, January 21\u201325). A Global Degree and Order 1200 Model of the Lunar Gravity Field Using GRAIL Mission Data. Proceedings of the 47th Annual Lunar and Planetary Science Conference, The Woodlands, TX, USA."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1415","DOI":"10.1002\/jgre.20097","article-title":"The JPL lunar gravity field to spherical harmonic degree 660 from the GRAIL Primary Mission","volume":"118","author":"Konopliv","year":"2013","journal-title":"J. Geophys. Res. E Planets"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1452","DOI":"10.1002\/2013GL059066","article-title":"High-resolution lunar gravity fields from the GRAIL Primary and Extended Missions","volume":"41","author":"Konopliv","year":"2014","journal-title":"Geophys. Res. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1676","DOI":"10.1002\/jgre.20118","article-title":"High-degree gravity models from GRAIL primary mission data","volume":"118","author":"Lemoine","year":"2013","journal-title":"J. Geophys. Res. E Planets"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"3382","DOI":"10.1002\/2014GL060027","article-title":"GRGM900C: A degree 900 lunar gravity model from GRAIL primary and extended mission data","volume":"41","author":"Lemoine","year":"2014","journal-title":"Geophys. Res. Lett."},{"key":"ref_34","unstructured":"Park, R.S., Konopliv, A.S., Yuan, D.N., Asmar, S., Watkins, M.M., Williams, J., Smith, D.E., and Zuber, M.T. (2015, January 14\u201318). A high-resolution spherical harmonic degree 1500 lunar gravity field from the GRAIL mission. Proceedings of the AGU Fall Meeting, San Francisco, CA, USA."},{"key":"ref_35","unstructured":"Zuber, M.T., Smith, D.E., Goossens, S.J., Neumann, G.A., Lemoine, F.G., Mazarico, E., Genova, A., and Rowland, D.D. (2016, January 21\u201325). Exploring the Depth Distribution of Lunar Crustal Mass Anomalies Using GRAIL Gravity and LOLA Topography. Proceedings of the 47th Lunar and Planetary Science Conference, The Woodlands, TX, USA."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1029\/2019JE006086","article-title":"High-Resolution Gravity Field Models from GRAIL Data and Implications for Models of the Density Structure of the Moon\u2032s Crust","volume":"125","author":"Goossens","year":"2020","journal-title":"J. Geophys. Res. Planets"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Lowrie, W. (2007). Fundamentals of Geophysics, Cambridge University Press.","DOI":"10.1017\/CBO9780511807107"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"131","DOI":"10.5140\/JASS.2014.31.2.131","article-title":"Lunar pit craters presumed to be the entrances of Lava caves by analogy to the Earth lava tube pits","volume":"31","author":"Hong","year":"2014","journal-title":"J. Astron. Space Sci."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0377-0273(98)00070-5","article-title":"Pit crater formation on Kilauea volcano, Hawaii","volume":"86","author":"Okubo","year":"1998","journal-title":"J. Volcanol. Geotherm. Res."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2574","DOI":"10.1029\/2018GC007529","article-title":"SHTools: Tools for Working with Spherical Harmonics","volume":"19","author":"Wieczorek","year":"2018","journal-title":"Geochem. Geophys. Geosyst."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"675","DOI":"10.1126\/science.1231753","article-title":"Ancient Igneous Intrusions and Early Expansion of the Moon Revealed by GRAIL Gravity Gradiometry","volume":"339","author":"Asmar","year":"2013","journal-title":"Science"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"671","DOI":"10.1126\/science.1231530","article-title":"The crust of the moon as seen by GRAIL","volume":"339","author":"Wieczorek","year":"2013","journal-title":"Science"},{"key":"ref_43","unstructured":"Watts, A.B. (2001). Isostasy and Flexure of the Lithosphere, Cambridge University Press."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"504","DOI":"10.1137\/S0036144504445765","article-title":"Spatiospectral concentration on a sphere","volume":"48","author":"Simons","year":"2006","journal-title":"SIAM Rev."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1111\/j.1365-246X.2005.02687.x","article-title":"Localized spectral analysis on the sphere","volume":"162","author":"Wieczorek","year":"2005","journal-title":"Geophys. J. Int."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"665","DOI":"10.1007\/s00041-006-6904-1","article-title":"Minimum-variance multitaper spectral estimation on the sphere","volume":"13","author":"Wieczorek","year":"2007","journal-title":"J. Fourier Anal. Appl."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Wieczorek, M.A. (2015). Gravity and Topography of the Terrestrial Planets. Treatise on Geophysics, Elsevier. [2nd ed.].","DOI":"10.1016\/B978-0-444-53802-4.00169-X"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1558","DOI":"10.1190\/1.1442807","article-title":"The gradient tensor of potential field anomalies: Some implications on data collection and data processing of maps","volume":"55","author":"Pedersen","year":"1990","journal-title":"Geophysics"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1016\/j.icarus.2019.05.027","article-title":"GRAIL-identified gravity anomalies in Oceanus Procellarum: Insight into subsurface impact and magmatic structures on the Moon","volume":"331","author":"Deutsch","year":"2019","journal-title":"Icarus"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"2445","DOI":"10.1002\/2015GL067394","article-title":"Identification of buried lunar impact craters from GRAIL data and implications for the nearside maria","volume":"43","author":"Evans","year":"2016","journal-title":"Geophys. Res. Lett."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/j.icarus.2017.02.013","article-title":"Detection and characterization of buried lunar craters with GRAIL data","volume":"289","author":"Sood","year":"2017","journal-title":"Icarus"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1029\/2010JE003731","article-title":"Remote compositional analysis of lunar olivine-rich lithologies with Moon Mineralogy Mapper (M3) spectra","volume":"116","author":"Isaacson","year":"2011","journal-title":"J. Geophys. Res. E Planets"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1029\/2011JE003990","article-title":"Geology of the King crater region: New insights into impact melt dynamics on the Moon","volume":"117","author":"Ashley","year":"2012","journal-title":"J. Geophys. Res. E Planets"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/16\/3926\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:08:06Z","timestamp":1760141286000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/16\/3926"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,12]]},"references-count":53,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2022,8]]}},"alternative-id":["rs14163926"],"URL":"https:\/\/doi.org\/10.3390\/rs14163926","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2022,8,12]]}}}