MOONQUAKES

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YERİN İÇİNDE HER BİR KARANLIK NOKTA DEPREMLERLE AYDINLIĞA ÇIKARILIYOR. HEM DÜNYA'DA HEM DE AY'DA. DEPREMLER OLMASA İNSANLIK OLARAK YERİN İÇLERİ HAKKINDA BİLGİCE SIFIR OLACAKTIK. KÂİNATTA YERİN İÇLERİNİ DEPREMLERLE AYDINLATIYORUZ. ÖNCE DÜNYA SONRA AY VE DAHA SONRA JEOFİZİK DEPREM KAYITÇISI KONULABİLEN HER YER AYDINLANACAK. JEOFİZİK SİSMOLOJİ ÇALIŞMALARI EVRENDE YERİN İÇİNDE DEPREMLERİ İZLEYEREK VE İNCELEYEREK KARANLIKTA KALAN SIR PERDELERİNİ KALDIRIYOR. DEPREMLER OLDUKÇA VEYA OLAN DEPREMLER JEOFİZİK KAYITÇILARLA DİNLENEBİLDİKÇE GEZEGENLERİN İÇİ SIR OLMAKTAN ÇIKACAK. İYİ Kİ DEPREMLER VAR VE İYİ Kİ DEPREM BİLİMİ JEOFİZİK SİSMOLOJİ VAR.
1969 YILINDA AY ÜZERİNE YERLEŞTİRİLEN 6 DEPREM İSTASYONU İLE AY DEPREMLERİ KAYIT EDİLMEYE BAŞLANDI VE AY BİZİM İÇİN JEOFİZİK SİSMOLOJİ ÇALIŞMALARIYLA AYDINLANDI. DEPREMLER YER İÇİNİ AYDINLATAN IŞIKTIR. DOĞRU DEĞİL Mİ?

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MOONQUAKES

  1. 1. History: The Apollo Missions • Starting in 1969 during the Apollo 12 mission, 6 seismic stations were installed • In the next 10 years, thousands of small scale (2-3) earthquakes were recorded • These earthquakes have since been classified into deep and shallow moonquakes
  2. 2. Moonquakes! By Kassandra Del Greco
  3. 3. Moonquake or Meteoroid • H-phase • Time from beginning of signal to maximum signal amplitude
  4. 4. Internal Structure of the Moon • Using moonquakes to determine there is mantle and core • Lack of evidence of deep moonquakes originating on the far-side may indicate a molten interior/core
  5. 5. Deep Moonquakes • 10 focus’ identified by 1971 although most moonquakes originated from the A1 • Depths of 600km-1000km (Moon’s radius 1737.4km) • Periodicity of moonquakes indicates they are induced by tides • Polarity reversal cycles can be attributed to a combination of tidal stress and a constant thermal stress
  6. 6. Tidal Stress • Deep moonquakes occur in monthly cycles • 7-month periodicities correlate to long-term gravity variations • Moonquakes occur at depths of max tidal stress
  7. 7. Other Sources of Stress • Slight expansion of the Moon by internal radiogenic heating or slight contraction on cooling • Localized strains due to uncompensated masses • Localized thermal stress
  8. 8. Sources of Stress • Cumulative amplitude curves with linear slope could indicate 3 types of stress • Thermal Stresses of possible volcanic origin • Tectonic Stresses at low stress levels • Dislocations along pre-existing fractures
  9. 9. Moonquake Swarms • Distinctive sequence of moonquakes closely grouped in space and time • Characterized by an abrupt beginning and ending of activity • Semi-monthly periodicity indicates lunar tide trigger • They do not have matching waveforms as regular deep moonquakes do • Suggested relation to volcanism as they are found on earth
  10. 10. Moonquake Swarms
  11. 11. Evidence Against Tectonics • Yearly seismic energy release in far below that of the earth • Internal convection leading to lunar tectonism is most likely absent • Much less heat is relased from the Moon than would be expected with convection • This would indicate that swarms are signs of continuing minor adjustment to crustal stresses
  12. 12. Conclusion • Moonquakes are cool (literally) • Unlikely tectonic association • Tidal stress • Studying the way seismic waves travel can give insight on the interior composition of the moon • More studies should be done
  13. 13. References Latham, G. V., M. Ewing, J. Dorman, D. Lammlein, F. Press, N. Toksöz, G. Sutton, F. Duennebier, Y. Nakamura (1972), Moonquakes and lunar tectonism, Moon, 4, 373–382. Nafi Toksoz, M., Groins, N.R., Cheng, C.H. (1977), Moonquakes: Mechanisms and Relation to Tidal Stresses, Science 27 May 1977: 196 (4293), 979-981. [DOI:10.1126/science.196.4293.979]. Nakamura, Y. (2005), Farside deep moonquakes and deep interior of the Moon, J. Geophys. Res., 110, E01001, [DOI:10.1029/2004JE002332].

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