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Tides as triggers of earthquakes in Hindu Kush. Verification of tidal movement of plates

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The intermediate-depth earthquakes (~200 km) in Hindu Kush, Afghanistan were investigated to prove their origin by tides. An untraditional astronomical method has been used to prove how astronomical parameters influence triggering of earthquakes. Earth rotation variations coincide exactly with larger earthquakes over 6th magnitude and tidal friction is responsible for vast earthquakes occurring almost daily of ~4th magnitude. Azimuth of Moon has been calculated for every earthquake and histograms constructed which revealed that earthquakes are triggered when Moon or Moon’s opposite force of tidal friction are on horizon on the east from earthquake epicenter. Calculated statistics prove almost absolute significance of astronomical parameters for earthquakes triggering.
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Tides as triggers of earthquakes in Hindu Kush. Verification of tidal
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movement of plates
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L. Ostřihanský
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Abstract
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The intermediate-depth earthquakes (~200 km) in Hindu Kush, Afghanistan were investigated
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to prove their origin by tides. An untraditional astronomical method has been used to prove
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how astronomical parameters influence triggering of earthquakes. Earth rotation variations
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coincide exactly with larger earthquakes over 6th magnitude and tidal friction is responsible
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for vast earthquakes occurring almost daily of ~4th magnitude. Azimuth of Moon has been
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calculated for every earthquake and histograms constructed which revealed that earthquakes
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are triggered when Moon or Moon’s opposite force of tidal friction are on horizon on the east
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from earthquake epicenter. Calculated statistics prove almost absolute significance of
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astronomical parameters for earthquakes triggering.
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Keywords Hindu Kush Earthquakes Tidal forces Earth rotation Astronomical parameters
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Moon’s azimuth rise ad set
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Introduction
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Many attempts have been made to prove earthquake triggering by tides in the past 100 years.
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There are negative results as of Schuster (1897), Knopoff (1964), Rydelek et al. (1992),
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Vidale et al. (1998) and many others. Positive results present Enescu and Enescu (1999),
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Stavinchi and Souchay (2003), Tanaka et al (2002, 2006), Cochran et al (2004). Even these
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positive results using sophisticated Schuster’s (1897) test present unconvincing results
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looking at their frequency earthquake histograms. They use rather amateur’s approach
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dividing distance between tidal maximums (Heaton 1975) or minimums (Tanaka et al 2002)
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into 0°- 360° phase angles corresponding earthquakes and elaborating histograms by
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Schuster’s test. I abandon this approach and present for solution astronomical data as Earth’s
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rotation speed, Moon’s azimuths during earthquake and Moon’s rises and sets. This way
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presents not only convincing histograms of earthquakes frequencies during earthquakes but
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shows also tectonic action of tides triggering earthquakes and introducing plates into
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movement. In 2007 Codicheanu et al. presented tidal triggering evidence of intermediate
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earthquakes in the Vrancea region (Romania) and 2008, 2012 Cadicheanu et al. also in Hindu
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Kush (Afghanistan). When they test the distribution determined from all phase angles of
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earthquakes, no correlation has been found. However when they selected a series of one year
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length sliding window with a 30 days moving step, they gained significant correlation
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between the tidal potential and earthquake occurrence for some windows.
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How tides drive lithospheric plates
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In 1991 the author (Ostřihanský 1997, 2015) derived the map from the no net rotation frame,
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but the zero point of the plate movement was chosen on the northern side of the Nazca plate
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in coordinate 5°S and 90°W. The movement of plates was divided into northward and
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westward components (Fig. 1). The northward component was attributed to tides because tidal
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torques directing northward (Fig. 2) are sufficiently strong (Ostřihanský 2015). Broz et al
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(2011) calculated for Moon 1.2 ×1022 Nm and for Sun 5.7 ×1021 Nm, using in both cases the
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same obliquity to equator 23.45°, The ratio of tidal action of Moon and Sun is therefore 2.1.
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The Sun has the 48 % share in tidal action. For this reason the share of Sun is very important
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for earthquake triggering and also for the plate movement. The most devastating earthquakes
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in the Indian plate the great 1934 Nepal earthquake was triggered in New Moon and 2004
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Sumatra earthquake in Full Moon (Ostřihanský 2015).
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The Eurasian plate, where the Hindu Kush deep seated seismic zone is situated, as the map
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(Fig 1) shows, moves only westward. Fig. 3 depicts the mechanism of the westward
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movement. It is a coordination of strong Earth rotation variations given by changing of
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Earth’s inertia moment as consequence Earth’s changing shape by tides and relatively weak
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force of tidal friction. This mechanism resembles to mechanical hammer driven by pneumatic
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or electric alternating force and pressure of human hand drilling concrete. The torque exerted
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by Earth’s rotation variations is 9.24 ×1021 Nm (Ostřihanský 2015), approximately equal to
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northward force. The torques of tidal friction were calculated by Burša 1(987a) on the basis of
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angular momentum balance in the Earth Moon Sun system. Using the formula for tidal
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variation in the component L of the orbital angular momentum of the Earth-Moon-Sun
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system, Burša (1987b) gets components of tidal torque N and Nm , Ns of Moon and Sun
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respectively
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N = Nm + Ns
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Nm = 3.5(ksinε) × 10 37 kg m2 cy-2
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Ns = 7.4(ksinε) × 10 36 kg m2 cy-2,
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where k, ε are global tidal parameters describing the elasticity parameters of the Earth as a
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whole, owing to ksinε = 0.012 and k = 0.70 resulting torques are
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Nm = 4.2 × 1035 kg m2 cy-2 = 4.2 ×1016 kg m2 s-2 = 4.2 × 1016 Nm
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Ns = 8.9 × 1034 kg m2 cy-2 = 8.9 × 1015 kg m2 s-2 = 8.9 × 1015 Nm
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Because the ratio of tidal torques of Moon and Sun is
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Nm/Ns = 4.7
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The Sun’s share in tidal friction is only 21% and corresponding tidal forces, considering
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distances rm = 3.84 × 108 m and rs = 1.5 × 1010 m,
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Fm = 1.1 × 108 kg m s-2
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Fs = 6.0 × 104 kg m s-2
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for Sun several orders of magnitude lower, in case of tidal friction the Sun’s share can be
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neglected.
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Hindu Kush "intermediate-depth" earthquakes zone and Earth’s rotation variations
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Whereas this isolated deep seated earthquake zone of depth about 200 km represents for
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supporters of mantle convection an unsolvable mystery, the author’s (Ostřihanský 2015)
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mechanism (Fig. 3) explains the triggering of earthquakes in this zone quite simply. Owing to
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westward movement of the Eurasian plate (Fig. 1), the part of subducted oceanic lithosphere
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of the Indian plate was torn off and shifted for several hundreds kilometers westward. Cross-
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sections through the Hindu Kush region suggest a near vertical northerly-dipping slab (Negredo et
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al., 2006, Searle et al., 2001, Searle 2013) firmly kept in lithosphere but moving with lower end
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through asthenosphere. Such body should be extremely sensitive to Earth rotation variations.
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Earthquakes selected from rectangle 400 x 300 km (Fig. 4) from Afghanistan and adjacent areas
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of Pakistan and Tajikistan cover the zone of the deepest earthquakes of Hindu Kush and confirm
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the west and east alternating movement evoked by Earths rotation variations (Fig. 3, right side).
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Figs. 5a, 6 and 7 show the plot of earthquakes and Earths rotation variation expressed as the
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length of day variations (LOD), for periods 2014-201, 2001-2002 and 1997-1998. Fig. 5b is more
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instructive, it shows an exact coincidence of earthquake 26.X.2015 with the largest LOD
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maximum, coinciding with Moons perigee. This largest Earths deceleration for the whole
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period 2014-2015 (Fig. 5a) is also increased by 5 times resonance effect. .The next deceleration
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shows earthquake 22.XI.2015, but for one day delayed. The earthquakes corresponding to the
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Earths accelerations 25.XII.2015 and 10.VIII.2015 are both for one day in advance. Fig. 6 shows
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the earthquake M 7.4, 3.III.2002 coinciding with the largest LOD maximum for the whole period
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2001-2002 and is for one day delayed. Relatively large earthquakes M 6.1 23.XI.2001 and M 6.2
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3.I.2002 do not coincide with LOD extremes and will be treated in the next paragraph. In Fig. 7,
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period 1997-1998, all earthquakes over 6th magnitude M 6.5, 13.V.1997, M 6.3, 17.XII.1997, M
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6.4, 20.II.1998, M 6.0, 21.III.1998 and M 6.9, 30.V.1998 coincide exactly with LOD minimum.
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The last earthquake is out of investigated depth range 80 300 km, for only 30 km depth.
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Hindu Kush "intermediate-depth" earthquakes zone and tidal friction
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Except of earthquakes triggered by Earth’s rotation variations, there are numerous
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earthquakes in Hindu Kush triggered almost daily or even more times in a day, which are of
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low magnitude about M = 4. To find origin of earthquakes, the histograms were constructed
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of Moon’s azimuths in the time of earthquakes. To construct histogram, it is necessary to
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perform correct interpretation with regard of tidal friction. Calculation of Moon’s azimuth for
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every earthquake presents quite random distribution between both variables. First
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modification of this distribution proceeds in omitting Moon’s azimuths below horizon and
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replace them by azimuths of bulging of force F2 (Fig. 3, left) opposite to force F1 with Moon.
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This is logic step because Moon below horizon can trigger earthquake e.g. in Indian Ocean
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but not in Eurasian plate. Figs .8a, 9a and 10a show these modified histograms and Figs 8b,
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9b and 10b these histograms in rose form for windows of azimuths width 20°. It is evident
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from histograms that most earthquakes are triggered when Moon is on the east or west from
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epicenter. Figs 11, 12 and 13 show the plot of these azimuths for all earthquakes including
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aftershocks. Let us make another logic presumption: If Moon is on the western hemisphere
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close to Moon’s set, the force which triggers earthquake is F2 (Fig. 3, left) opposite to Moon
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in tidal friction because only force of tidal bulging on the east from epicenter can move
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lithosphere westward and trigger earthquake. On the contrary when force F2 is on the western
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hemisphere below horizon, the Moon with force F1 on eastern hemisphere rises and triggers
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earthquake. To generalize this finding let us calculate azimuths of Moon rises and Moon sets
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(red curves on Figs 11. 12 and 13) and subtract Moon rises from Moon’s azimuths
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corresponding earthquakes for only eastern horizon, i.e. for azimuths - 180°. Plotting these
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values in histogram (Figs 14, 15, 16), results in reliable proof that tidal bulging before
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(negative angles) horizon and after horizon (positive values) trigger earthquakes. Figures 11
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abcd show consequent procedure of investigation: Fig. 11a shows azimuths of Moon and
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opposite bulging earthquakes above horizon, Fig. 11b shows all azimuths of Moon and
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opposite bulging earthquakes on eastern horizon 0°- 180°. Fig. 11c shows differences between
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azimuths of Moon rise and Moon or opposite bulging azimuth of earthquake. This is the final
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result for histogram. Fig 11 d shoes in detail azimuths of Moon and aftershocks of strong
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earthquake of M 7.5 26.X.2015 at 09:49:38 UTC and aftershock M 4.0 at 11:14:43 UTC.
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Opposite bulging (white disk) triggered after 12 hours, exactly at 23:35:20 earthquake of M
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4.1. It can be supposed that stronger tides trigger earthquakes sooner before reaching horizon.
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Force of the northward movement, as evident from Fig. 2, was situated in tangential
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position to lithosphere. Similarly the westward force should be situated in tangential position
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to lithosphere and is situated on horizon on the east from epicenter. Vertical component of
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tidal force uplifting Earth’s crust for several decimeters cannot have any effect on the bottom
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of lithosphere in depth of 200 km. For this reason when Moon moves over meridian, 180°
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azimuth triggers no earthquakes.
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. It is supposed that the horizon is on eastern side because tidal friction acts westward
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against Earth’s rotation and triggers earthquakes by pressure directing westward. Analogically
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negative values mark tidal forces acting below horizon and positive values forces above
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horizon. Distinguishing maximum number of earthquakes in 0 histogram bin proves
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semidiurnal tidal triggering by tidal friction in intermediate-depth earthquakes in Hindu Kush,
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which can be also proven by Schuster’s test (Figs 14, 15 and 16).
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It is difficult to establish what causes the great scattering of azimuths. Fig. 17 shows
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exceptional case of relatively stable Earth rotation speed from 10 to 19. I. 2015. If the speed
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were constant, azimuths were stable in about 120°. Any LOD increment results in great
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scatter but most of azimuths are on horizon. Next example (Fig. 18), azimuths of aftershocks
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of earthquake M 7.5, 26.X.2015 during LOD maximum show large scatter, but more detailed
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investigation is required. Correlation of S2 tidal constituent with earthquakes (Codicheanu et
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al., 2008) may be explained by solar irradiation and creation of thermoelastic wave (Kalenda
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et al. 2012).causing detectable motions of lithosphere.
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Earthquakes M 6.1, 23.XI.01 and M 6.2, 3.I.01 (Fig. 6), not coinciding with LOD extremes,
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are evidently triggered by tidal friction in spite that stay aside of usual magnitude about 4.
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because they were affected also by gravity. In subduction zones gravity subsidence plays
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important role and in Hindu Kush heavy oceanic lithosphere in some cases subsides triggering
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earthquakes of larger magnitudes. Differential Moon’s angles (distances from horizon + 4.6°
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and +20.0° respectively). confirm tidal friction origin of these earthquakes.
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Not all earthquakes should be triggered by forces in tangential position to lithosphere. Fig.
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19 shows high position of Moon in 180° during earthquake M 8.6, 28.III.2005 Sumatra above
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epicenter. Ocean loading tides trigger earthquakes by forces perpendicular to lithosphere.
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Comments of Professor Duncan Agnew to presented paper
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Professor Agnew:
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25-30: it is unclear why astronomical features should be "better": what
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matters is stress changes, which may or may not correlate with this
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assortment of azimuths and speeds.
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Author’s answer:
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Creation of the plate movement was given on the Earth by inclined Earth rotation axis
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resulting of large torques acting on plates in northward direction 1.8 × 1022 N m and westward
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direction = 9.24×1021 N m. (Ostrihansky, L. Tides as drivers of plates and criticism of
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mantle convection, Acta Geodaetica et Geophysica: Volume 50, Issue 3 (2015), Page 271-
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293, DOI: 10.1007/s40328-014-0080-6).
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Professor Agnew:
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39-77: I realize that the author is convinced that tidal torques drive the
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plates, but there is a strong argument against this (T.H. Jordan, Some comments
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on tidal drag as a mechanism for driving plate motions J. Geophys. Res., 79
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(14) (1974), pp. 21412142) that he does not address. Another recent paper on
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this (which should have been cited: Riguzzi, F., G. Panza, P. Varga, and C.
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Doglioni (2010), Can Earth's rotation and tidal despinning drive plate
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tectonics?, (Tectonophys., 484, 60-73) admits the difficulty but tries to get
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around it by assuming a low-viscosity zone for which there is no real evidence.
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The author's claims cannot be accepted.
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Author’s answer:
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T.|H. Jordan has incorrect imagination comparing the Earth to rotational viscosimeter.
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Really, his calculation of viscosity uses formulas like from the instruction manual for
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viscosimeter. Better imagination presets Fig. 3 of my paper comparing the Earth to automatic
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hammer, where pneumatic or electric strong alternating movement enables drilling of
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concrete only by pressure of hand. I.e.: Alternating torque beneath lithosphere and tidal friction
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kept in rotation frame with the Moon’s orbit facilitate the movement of lithosphere westward.
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The paper of Riguzzi et al. (2010) was also useless for me because only tidal friction is
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considered and I agree with you that such a weak force requires low viscosity zone for which
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is no evidence. Nevertheless these two papers were many times cited in my previous papers.
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Professor Agnew
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91-103: Without statistical testing, claims of correlating individual
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earthquakes and something else (in this case LOD) are worthless. LOD changes
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are not associated with any torques, and the associated accelerations are
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tiny (the velocity changes are a few micrometers/sec, and the accelerations
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are 10**-12g). No explanation of "resonance enlargement" is provided.
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Also, LOD changes are not associated with changes in torque.
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Author’s answer:
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LOD variations are caused by changing Moon’s and Sun’s declinations by which the Earth is
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deformed. Resulting velocity changes exerts torques which are not tiny but reaches values
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stated above exceeding in many cases seismic moments.
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Tidal resonances are very common in ocean tides and there is no reason not to be in solid
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tides. Their existence is evident from Fig. 5a where consequently increasing LOD maxima
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end with Moon’s perigee. Effect of resonances is evident on many large earthquakes as
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Gorkha 2015, HinduKush 2015, Denali Fault 2002 and others.
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Professor Agnew:
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110-158 (Figures 8-10). These bimodal distributions (which the author
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claims are not significant) have nothing to do with tidal forces, but just
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the nature of the thing being looked at: lunar azimuth. Subsequent figures
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show that this is periodic over time within a limited range. But since a
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sinusoid is near its extremes for more time than it is between them, sampling
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a sinusoid at random times (of earthquakes) will always produce a bimodal
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pattern like the ones shown here. This can be dealt with by (as Vidale et
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al did) comparing any result for times of earthquakes with the same thing
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with the times being chosen randomly.
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Author’s answer:
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Reviewer’s description of bimodal distribution is quite incorrect. Simply: Temperatures on
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the Earth fit to Sun’s azimuth sinusoid, earthquakes fit to Moon’s azimuth sinusoid. The only
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difference is that both effects are in reciprocal position. Bimodal distribution of earthquakes
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we simply remove, realizing following: Figures 8-10 show that earthquakes are triggered in
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moment when Moon is on east or west, i.e when rises or sets. It is necessary to realize that if
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the Moon’s bulging is over local meridian no earthquake can be triggered. But the earthquake
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is triggered by opposite bulging F2 on eastern side of tidal friction force couple. Great
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improvement of statistics will come, considering that Moon’s azimuth depends also on
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Moon’s declination, calculating Moon rises for every earthquake and subtracting Moon’s or
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opposite bulging azimuths from Moon’s rises, we get two parameters azimuth and declination
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correlating with earthquakes. Therefore the time of the earthquake is stated univocally. It is
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triggered when Moon’s bulges are on eastern horizon. You mention your paper from
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California.(Vidale, Agnew et al. Absence of earthquake correlation with Earth tides: An
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indication of high preseismic fault stress rate. JGR 103, 24567-24572, 1998). In Hindu Kush
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the Eurasian plate moves only westward and for this reason when tidal bulge is on eastern
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horizon, the lithospheric plate is pushed westward and triggers earthquake colliding with
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remnant of oceanic lithosphere. In California the movement of the plate is given by force of
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tidal friction coming from the east and by northward force coming from the south. Maximum
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vectorial resultant of both forces move the plate and by this movement earthquakes on San
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Andreas and Calaveras Faults can be triggered. This movement is evident from GPS and by
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right lateral shift detectable on the fault after earthquake. Tidal stresses derived from CSR3.0
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global tide model and tides of San Francisco Bay (Agnew 1997) cannot trigger any
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earthquakes, unless we consider ocean loading effects, but Pacific Ocean is far and vertical
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movements on mentioned faults were not detected.
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Simple advice can be given to Afghan people living in Hindu Kush area. Small earthquakes
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are triggered mostly before or after Moon rise or Moon set. Stronger earthquakes are triggered
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during large LOD variations, which IERS predicts several months in advance.
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Data acquisition
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The ANSS Catalog Search has been used for all seismic data selected from rectangle 35°N -
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38°N and 69°E - 74°E (300 x 400) km in Afghanistan and adjacent part of Pakistan and
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Tajikistan, Intermediate depth earthquakes were from range 80 300 km of 2nd 8th
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magnitude. Earth’s rotation speed has been acquired from length of day variations of IERS
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http://hpiers.obspm.fr/eop-pc/ EOP 08 C04 IAU 2000 62-now, html solution. Moon’s
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azimuths were calculated from Sun or Moon Altitude/Azimuth table, Form B of the US Naval
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Observatory, Astronomical Application Dept. in Universal time (Time zone 0) the same as
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earthquakes in ANSS Catalog and geographic coordinates of epicenter. Because the table is
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given only for Moons azimuths above horizon, 180° were added to longitude or 12 hours were
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added to time of earthquake. Both values differ for several degrees owing to Moon’s own
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movement. By this way the Moon’s azimuths and azimuths of F2 force were used, both
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situated on hemisphere with earthquake epicenter. For further elaboration,. Heavens Above
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Calculator presenting directly Moon’s azimuths below horizon were found also suitable.
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Azimuths were acquired from Moon Rise/Set Times of M.A.S. Observatory, 8851 White
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Road, Muskegon, Michigan. Lunar Perigee and Apogee were from John Walker’s Calculator.
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In histograms, results of Schuster’s test and total earthquake numbers are inserted. Formulas
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for Schuster’s test are given in Heaton (1975) or Tanaka et al. (2002) and many others.
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Conclusion
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Correct understanding of mechanism of tidal friction revealed the tidal origin of earthquakes
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in Hindu Kush. Seemingly random distribution of Moon’s azimuths with earthquakes can be
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transferred into principle dependence of both variables using astronomical calculations of
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Moon’s azimuths, azimuths of Moon’s rises and sets, understanding action of both sides of
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tidal force couple, and Earth’s rotation variation which acts as amplifier of weak tidal friction
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force. It is necessary to take into account Moon’s declination which by its positive and
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negative values limits the range of Moon’s azimuths over sky. (See Figs 11, 12 and13 how
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curves of Moon rises and sets limits extent of Moon’s azimuths and how most of Moon’s
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azimuths are on these curves coinciding with horizon). From it follows the mechanism of tidal
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triggering because only forces F1 and F2 of tidal friction (without regard of Moon’s position)
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situated on eastern horizon from epicenter can move lithosphere westward and trigger
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earthquakes. This modification of Moon’s azimuths presented convincing proof of tidal
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triggering of earthquakes, solving the problem scientists dealt with for more than 100 years.
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Cochran, E. S., Vidale, T. E., and Tanaka, S. (2004) Earth tides can trigger shallow thrust
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earthquakes correlation with Earth tides, an indication of high preseismic faultstress
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rate, J. Geophys. Res., 103, 24567-24572.
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Fig. 1 shows the real plate movements in 10 M.Y. over mantle. The map is derived from the
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no net rotation frame, but the zero point of the plate movement was chosen on northern side
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of the Nazca plate in coordinates 5° S and 90° W (Ostřihanský 1997).
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Fig. 2. Positron of Moon, Earth and Sun during the earthquakes 26th December 2004.
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Evidently the largest northward torque on the Indian plate was at midnight. Fm and Fs are
348
tidal forces of Moon and Sun acting on Earth’s rotational flattening. Northward directing
349
component of tidal force pushes the Indian plate northward out of equator
350
(Äquatorfluchtkraft). After ½ of solar day the tidal force acts in opposite direction against the
351
mid-ocean ridge without any effect on the plate movement.
352
16
353
Fig. 3. The explanation of the westward movement is more complicated. The torque exerted by tidal
354
friction is low, always considered as insufficient for the plate movement. Calculation of the torque
355
exerted by Mf and Mtm LOD frequency owing to large amount of the whole mass of mantle gives
356
again large value reaching 1022 N m (Ostřihanský 2015). Alternating torque beneath lithosphere and
357
tidal friction kept in rotation frame with the Moon’s orbit facilitate the movement of lithosphere
358
westward. Many examples show how body could slide only after shaking.
359
17
Fig. 4 Rectangle marks chosen investigated area of Hindu Kush intermediate-depth seismic
360
zone situated in Afghanistan and in adjacent parts of Pakistan and Tajikistan.
361
362
363
364
365
366
367
26.X.2015 M 7.5
AFGHANISTAN
TAJIKISTAN
PAKISTAN
18
Hindu Kush LOD variations and earthquakes 2014-2015
0
1
2
3
4
5
6
7
8
1.11.2014
1.12.2014
1.1.2015
1.2.2015
1.3.2015
1.4.2015
1.5.2015
1.6.2015
1.7.2015
1.8.2015
1.9.2015
1.10.2015
1.11.2015
1.12.2015
1.1.2016
Date
Eartquake magnitude
0
0,0005
0,001
0,0015
0,002
0,0025
Length of day - 86400 s
M 7.5, 26.X.2015
1
2
3
5
Resonances
perigee
apogee
4
3
368
Fig. 5a Resonance enlargement of earthquake M 7.5 26.X.2015 by the consequent 5 Earth
369
rotation decelerations and almost daily triggering of earthquakes by tidal friction of about 4th
370
magnitude.
371
372
0
1
2
3
4
5
6
7
8
29.7.2015
5.8.2015
12.8.2015
19.8.2015
26.8.2015
2.9.2015
9.9.2015
16.9.2015
23.9.2015
30.9.2015
7.10.2015
14.10.2015
21.10.2015
28.10.2015
4.11.2015
11.11.2015
18.11.2015
25.11.2015
2.12.2015
9.12.2015
16.12.2015
23.12.2015
30.12.2015
Date
Earthquake magnitude
0
0,0005
0,001
0,0015
0,002
0,0025
Length of day - 86400 s
M 7.5, 26.X.2015
M 5.8, 22.XI.2015
M 6.3,
25.XII.2015
M 5.9, 10.VIII.2015
perigee
apogee
373
Fig. 5b Exact coincidence of earthquake M 7.5 26.X.2015 with LOD maximum (deceleration) and
374
Moon’s perigee. Earthquake M 5.0 22.XI.2015 coincides also with Earth deceleration but with one day
375
delay. Earthquakes M 6.3 26.XII.2015 and M 5.9 10.VIII.2015 coincide with Earth’s acceleration but
376
one day in advance.
377
378
379
380
381
382
383
384
19
Hindu Kush LOD variations and earthquakes 2001-2002
0
1
2
3
4
5
6
7
8
2.7.2001
2.8.2001
2.9.2001
2.10.2001
2.11.2001
2.12.2001
2.1.2002
2.2.2002
2.3.2002
2.4.2002
2.5.2002
2.6.2002
2.7.2002
Date
Earthquake magnitude
-0,001
-0,0005
0
0,0005
0,001
0,0015
0,002
Length of day - 86400 s
M 7.4, 3.III.2002
apogee perigee
M 6.1
M 6.2
385
386
Fig. 6 shows the earthquake M 7.4, 3.III.2002 coinciding with the largest LOD maximum for the
387
whole period 2001-2002 and is for one day delayed. Relatively large earthquakes M 6.1
388
23.XI.2001 and M 6.2 3.I.2002 do not coincide with LOD extremes. Both earthquakes are of tidal
389
friction origin enlarged by subsidence of heavy oceanic slab.
390
391
Hindu Kush LOD variations and earthquakes 1997-1998
0
1
2
3
4
5
6
7
8
1.5.1997
1.6.1997
1.7.1997
1.8.1997
1.9.1997
1.10.1997
1.11.1997
1.12.1997
1.1.1998
1.2.1998
1.3.1998
1.4.1998
1.5.1998
1.6.1998
1.7.1998
1.8.1998
1.9.1998
1.10.1998
1.11.1998
1.12.1998
Date
Earthquake magnitude
0
0,0005
0,001
0,0015
0,002
0,0025
0,003
Length of day - 86400 s
M 6.5
M 6.3
M 6.4
M 6.0
M 6.9
perigee apogee
392
Fig. 7 All earthquakes over 6th magnitude M 6.5, 13.V.1997, M 6.3, 17.XII.1997, M 6.4,
393
20.II.1998, M 6.0, 21.III.1998 and M 6.9, 30.V.1998 coincide exactly with LOD minimum. The
394
last earthquake is out of investigated depth range 80 300 km. It is only in depth of 30 km.
395
396
397
398
399
20
400
a
401
Histogram Hindu Kush 2014-2015
0
5
10
15
20
25
30
35
020 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360
Moon's azimuth (deg)
Number of earthquakes
Schuster's test p = 16,8 %
N = 241
402
403
b
404
Histogram Hindu Kush 2001-2002
0
5
10
15
20
25
30
35
020 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360
Moon's azimuth (deg)
Numberr of earthquakes
Schuster's test p = 30.8 %
N = 206
405
c
406
21
Histogram Hindu Kush 1997-1998
0
5
10
15
20
25
30
35
40
45
50
020 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360
Moon'a azimuth (deg.)
Number of earthquakes
Schuster's test p = 74.9 %
N = 224
407
Figs 8a, 9a and 10a show histograms of earthquakes distribution in Moon’s azimuths of 20° width.
408
Shuster’s test value p > 5% is considered as statistically insignificant. N is total number of
409
earthquakes.
410
411
b
c
22
Figs 8b, 9b and 10b show the previous histograms in rose form. It is evident from histograms that
412
most earthquakes are triggered when Moon is on the east or west from epicenter.
413
414
11
415
Hindu Kush Moon's azimuths during earthquakes 2014-2015
0
60
120
180
240
300
360
1.11.2014
1.12.2014
1.1.2015
1.2.2015
1.3.2015
1.4.2015
1.5.2015
1.6.2015
1.7.2015
1.8.2015
1.9.2015
1.10.2015
1.11.2015
1.12.2015
1.1.2016
Date
Azimuth of Moon (degrees)
0
0,0005
0,001
0,0015
0,002
0,0025
Lenfth of day - 86400 s
Moon rise
Moon set
416
Fig. 11a Azimuths of Moon (violet squares) and opposite tidal bulging (black squares)
417
corresponding earthquakes above horizons.
418
HinduKush Moon's azimuths during earthquakes 2014-2015
on eastern horizon
0
20
40
60
80
100
120
140
160
180
1.11.2014
1.12.2014
1.1.2015
1.2.2015
1.3.2015
1.4.2015
1.5.2015
1.6.2015
1.7.2015
1.8.2015
1.9.2015
1.10.2015
1.11.2015
1.12.2015
1.1.2016
Date
Azimuth of Moon
(degrees)
0
0,0005
0,001
0,0015
0,002
0,0025
Length of day - 86400 s
Moon rise
Length of day
419
Fig. 11b Azimuths of Moon and opposite tidal bulging above and below eastern horizon.
420
421
23
HinduKush differences of Moon and tidal bulging from from Moon
rise
-150
-120
-90
-60
-30
0
30
60
90
120
150
1.11.2014
1.12.2014
1.1.2015
1.2.2015
1.3.2015
1.4.2015
1.5.2015
1.6.2015
1.7.2015
1.8.2015
1.9.2015
1.10.2015
1.11.2015
1.12.2015
1.1.2016
Date
Azimuthal distance of
Moon or next tidal
bulging from eastern
horizon
0
0,0005
0,001
0,0015
0,002
0,0025
Length of day-86400 s
Horizon
422
Fig. 11 c Azimuthal difference of Moon and opposite tidal bulging from eastern horizon
423
424
Moon and aftershock positions during Hindu Kush M 7.5
26.X.2015 earthquake
-40
-30
-20
-10
0
10
20
30
40
50
60
70
40 60 80 100 120 140 160
Azimuth (deg)
Azimuthal Moon's distance
from eastern horizon (deg)
Horizon
Moon rise
M 7.5
M 4.8
Next bulging M 4.1
M 4.0
M 4.4
M 4.1
M 4.0
M 4.5
425
Fig. 11d Earthquake Hindu Kush M 7.5 26.X.2015 was triggered at 09:09:32 UTC under azimuth
56.6° and aftershock M 4.0 at 11:14:43 UTC.under azimuth 77.8°. Next bulging which occurred
after 12 hours at 23:35:20 UTC under azimuth 74.6° triggered earthquake M 4.1 (white disc).
Figure shows that stronger earthquakes can occur several degrees before rise above horizon.
.:
426
427
428
429
430
431
24
12
432
Hindu Kush Moon's azimuths during earthquakes 2001-2002
0
60
120
180
240
300
360
2.7.2001
2.8.2001
2.9.2001
2.10.2001
2.11.2001
2.12.2001
2.1.2002
2.2.2002
2.3.2002
2.4.2002
2.5.2002
2.6.2002
2.7.2002
Date
Azimuth of Moon (degrees)
-0,001
-0,0005
0
0,0005
0,001
0,0015
0,002
Length of day - 86400 s
Moon rise
Moon set
433
Fig. 12a Azimuths of Moon and opposite tidal bulging corresponding earthquakes above
434
horizons.
435
13
436
Hindu Kush Moon's azimuths during earthquakes 1997-1998
0
60
120
180
240
300
360
1.5.1997
1.6.1997
1.7.1997
1.8.1997
1.9.1997
1.10.1997
1.11.1997
1.12.1997
1.1.1998
1.2.1998
1.3.1998
1.4.1998
1.5.1998
1.6.1998
1.7.1998
1.8.1998
1.9.1998
1.10.1998
1.11.1998
1.12.1998
Date
Azimuth of Moon (degrees)
0
0,0005
0,001
0,0015
0,002
0,0025
0,003
Length of day - 86400 s
Moon rise
Moon set
437
438
Figs 11, 12 and 13 show the plot of Moon’s azimuths from all earthquakes including
439
aftershocks. Red squares mark Moon’s azimuths above horizon, black ones below horizon. In
440
Fig. 12 it is not distinguished because this division is unimportant. In fact black squares mark
441
azimuth of force F2 reverse to Moon because for calculation the NO Observatory calculator
442
was used not presenting Moon’s azimuth below horizon. Moon’s azimuths below horizon
443
were transferred to F2 adding to longitude 180° (see further explanation in column Data
444
acquisition). Plot LOD is included because Earth’s rotation variations are considered as a
445
factor responsible for azimuth-earthquakes scattering.
446
25
447
14
448
Differential histogram HinduKush 2014-2015
(all eastern horizon data)
0
10
20
30
40
50
-120 -100 -80 -60 -40 20 020 40 60 80 100 120
Azimuthal distance of tidal bulging from eastern horizon (deg)
Number of earthquakes
Schuster's test p = 2.8×10-25 %
N = 217
449
450
451
452
453
15
454
Differential histogram Hindu Kush 2001-2002
0
10
20
30
40
50
60
-120 -100 -80 -60 -40 20 020 40 60 80 100 120
Angle distance of tidal bulging from eastern horizon (deg)
Number of earthquakes
Schuster's test p = 2.9×10-31 %
N = 196
455
456
16
457
26
Differential histogram Hindu Kush1997-1998
0
5
10
15
20
25
30
35
40
45
50
-120 -100 -80 -60 -40 20 020 40 60 80 100 120
Angle distance of tidal bulging from eastern horizon (deg)
Number of earthquakes
Schuster's test p = 1.0×10-9 %
N = 215
458
Figs 14, 15 and 16 presents statistically significant histograms gained by subtracting Moon’s
459
and opposite tidal bulging azimuths < 180° from azimuths of Moon rises on eastern horizon.
460
This calculation presents positive and negative angles, positive for Moon’s or for opposite
461
side tidal friction couple force above horizon and negative angles for Moon’s and for opposite
462
tidal friction couple force below horizon. Constructing histograms Figs 14, 15 and 16 presents
463
significant statistical results of Schuster’s values p << 5 %.
464
465
466
0
60
120
180
240
300
360
1.1.2015
3.1.2015
5.1.2015
7.1.2015
9.1.2015
11.1.2015
13.1.2015
15.1.2015
17.1.2015
19.1.2015
21.1.2015
23.1.2015
25.1.2015
27.1.2015
29.1.2015
31.1.2015
2.2.2015
Date
Azimuth of Moon (deg)
0
0,0002
0,0004
0,0006
0,0008
0,001
0,0012
0,0014
0,0016
0,0018
Length of day - 86400 s
Moon rise
Moon set
467
Fig. 17 shows exceptional case of relatively constant Earth’s rotation speed from 10 to 19. I.
468
2015 and Moon’s azimuths along 120°. Any Earth’s rotation variations result in azimuth
469
scatter. It is also evident position of most of Moons azimuths on horizon during Moon rise
470
and Moon set.
471
472
27
Hindu Kush Azimuths of aftershocks of M 7.5, 26.X.2015
0
60
120
180
240
300
360
6.10.2015
8.10.2015
10.10.2015
12.10.2015
14.10.2015
16.10.2015
18.10.2015
20.10.2015
22.10.2015
24.10.2015
26.10.2015
28.10.2015
30.10.2015
1.11.2015
3.11.2015
5.11.2015
7.11.2015
9.11.2015
11.11.2015
13.11.2015
15.11.2015
17.11.2015
Date
Azimuths of Moon
0
0,0005
0,001
0,0015
0,002
0,0025
Length od day - 86400 s
Moon rise
Moon set
M 7.5, 26.X.2015
473
Fig. 18 The scatter of aftershocks of earthquake M 7.5, 26.X.2015 azimuths during Earth’s
474
rotation decrease (LOD maximum). It is evident that LOD variations cause the scatter of
475
Moon’s azimuths. Arrow marks F2 bulging of M 7.5 earthquake 26.X.2015 azimuth 241.1°.
476
Moon’s F1 bulging is not depicted because owing to its 56.6° azimuth is below horizon.
477
478
479
480
M 8.6 Sumatra 28.III.2005 earthquake origin
0
60
120
180
240
300
360
25.3.2005
27.3.2005
29.3.2005
31.3.2005
2.4.2005
4.4.2005
6.4.2005
8.4.2005
10.4.2005
12.4.2005
14.4.2005
16.4.2005
18.4.2005
20.4.2005
22.4.2005
24.4.2005
26.4.2005
28.4.2005
30.4.2005
2.5.2005
Date
Azimuth of Moon
0
2
4
6
8
10
12
14
16
18
20
Earthquake magnitude
M 8.6 Sumatra 28.III.2005 earthquake
481
Fig. 19 explains origin of earthquake M 8.6 Sumatra 28.III.2005 in (Ostřihanský 2015, Fig
482
20), where two explanations have been suggested: by tidal friction or by waste flooding after
483
tsunami. Figure confirms both possibilities. Loading by ocean tides is confirmed by Moon's
484
azimuths around 180° from 28.II. to 2.IV. 2005, other azimuths confirm tidal friction.
485
Because Sumatra is in equatorial region, between 8.IV and 23.IV Moon coincided with zenith
486
and azimuths could not be calculated because in such position they are indefinite. This
487
confirms also high position of Moon above epicenter.
488
28
489
490
... In Hindu Kush earthquakes are triggered exactly when Moon or opposite tidal bulging are on eastern horizon. (Ostřihanský 2016). In Central Italy it should not be always true owing to shallow earthquakes. ...
... The detailed investigation of 6 th April 2009 earthquake showed that earthquakes are situated on the western side of normal faults and considering the trend of destruction intensity, it is shown that hanging wall blocks move during the Earth's deceleration westward. Earthquakes triggered during the Earth's acceleration on thrust faults confirm eastward compression and possible eastward movement of hanging wall blocks (Ostřihanský 2010) In 2015(Ostřihanský 2015a,.2016) very important investigations have been performed in Hindu Kush proving that earthquakes occur when Moon is on eastern horizon and earthquakes coincide with LOD maximum (Earth's deceleration). ...
Conference Paper
Full-text available
Two steps were performed: (1) seeking correlation of earthquakes with Earth's rotation variation extremes and (2) statistical evaluation of histograms constructed from distribution of Moon's hour angles with earthquakes. Examined earthquakes were: Norcia 1979 (M = 5.9), Calfiorito 1997 (M max = 5.9), L'Aquila 2009 (M = 6.3) and Rieti 2016 (M = 6.2), triggered in the Earth's rotation deceleration and comparison with tectonics shows their position on the normal faults. The normal fault (dipping westward) earthquakes are triggered during the Earth's deceleration and the thrust fault earthquakes are triggered during the Earth's acceleration. A special part of the length of day (LOD) graph was distinguished in 2002 – 2005 period of maximum Earth's velocity, comprising almost continuous series of low magnitude earthquakes. Histograms of Moon's hour angles show no convincing correlation with local meridian. However histograms show convincing correlation of earthquakes occurrence in Moon's position on eastern horizon. This confirms the action of tidal friction force driving the Eurasian plate over the subduction zone of Tyrrhenian Sea. The most convincing proof of tidal triggering of earthquakes in Central Italy is the periodic repetition of earthquakes: Norcia 1979, Colfiorito 1997 and Rieti 2016 in nodal Moon's 18.61 years period.
... For verification of this claim two plates were chosen, i.e. the Eurasian plate which exclusively moves westward and the Indian plate which moves almost exclusively northward (Fig. 5). Results of earthquakes triggering in dependence of tidal forces actions are thoroughly presented in papers (Ostřihanský 2016a and2016b). Let us present only strict results. ...
Presentation
Full-text available
The intermediate-depth earthquakes (~200 km) in Hindu Kush, Afghanistan were investigated to prove their origin by tides. An untraditional astronomical method has been used to prove how astronomical parameters influence triggering of earthquakes. In contrast to previous issues, where Moon hour angles were used, Moons declinations were used successfully to prove tidal origin of earthquakes. Maximum earthquakes have been recognized during minor lunar standstills, i.
Article
Full-text available
Because the rate of stress change from the Earth tides exceeds that from tectonic stress accumulation, tidal triggering of earthquakes would be expected if the final hours of loading of the fault were at the tectonic rate and if rupture began soon after the achievement of a critical stress level. We analyze the tidal stresses and stress rates on the fault planes and at the times of 13,042 earthquakes which are so close to the San Andreas and Calaveras faults in California that we may take the fault plane to be known. We find that the stresses and stress rates from Earth tides at the times of earthquakes are distributed in the same way as tidal stresses and stress rates at random times. While the rate of earthquakes when the tidal stress promotes failure is 2% higher than when the stress does not, this difference in rate is not statistically significant. This lack of tidal triggering implies that preseismic stress rates in the nucleation zones of earthquakes are at least 0.15 bar/h just preceding seismic failure, much above the long-term tectonic stress rate of 10-4 bar/h.
Article
Full-text available
We observe tidal triggering of earthquakes by measuring the correlation between the Earth tide and earthquake occurrence. We used the times, locations, and focal mechanisms of the 9350 globally distributed earthquakes with magnitude 5.5 or larger from the Harvard centroid moment tensor catalog. The tidal stress was theoretically computed by using the Preliminary Reference Earth Model and a recent ocean tide model, NAO.99b. We considered the shear stress on the fault plane and the trace of stress tensor, J1. Defining the tidal phase angle at the occurrence time for each earthquake, we statistically tested the phase selectivity using the Schuster's method. For all the earthquakes, no significant correlation is found between the Earth tide and earthquake occurrence both for the shear stress and for J1. By classifying the data set according to fault types, however, we find a high correlation with the shear stress for reverse fault type. The correlation is particularly clear for shallow and smaller earthquakes of this type. Significant correlation with J1 also appears for larger earthquakes of reverse fault type and for shallow and larger ones of normal fault type. We find no correlation for strike-slip type. For all the cases of high correlation, earthquakes tend to occur when the tidal stress accelerates the fault slip, indicating that high correlation is not coincidental but is physically justified. This result strongly suggests that a small stress change due to the Earth tide encourages earthquake occurrence when the stress in the future focal area is near a critical condition.
Article
Full-text available
Coesite eclogites and diamond-bearing ultrahigh-pressure (UHP) metamorphic rocks along ancient plate boundaries were mostly derived from quartz-and carbonate-bearing rocks originally formed close to the earth's surface. Their mineral assemblages and PT conditions require that they were subducted to depths of 90–130 km (27–40 kbar) and then brought back to the surface, still retaining evidence of their UHP formation. The geological record shows that continental-derived UHP rocks can be formed by subduction of thinned continental-margin crust beneath ophiolites (e.g., Oman ophiolite, west Himalayan ophiolites) or beneath island arcs (e.g., Kohistan Arc, Pakistan) as well as in continent-continent collision zones (e.g., Dabie Shan–Sulu Belt, Kazakhstan, western Norway, Alps). We present a model, based on the geometry of the seismically active Hindu Kush continental subduction zone and its restoration, assuming present-day plate motions, which explains how surficial graphite-rich shales and carbonates deposited along the northwest Indian plate margin were dragged down to these depths, anchored by the eclogitized leading edge of the thinned Indian plate crust. We suggest that coesite eclogite and diamond-bearing UHP metamorphism is occurring today at depth along the Hindu Kush seismic continental subduction zone.
Article
The ways by which earthquakes could influence the Earth’s rotation and, in a reciprocal way, the Earth tides could possibly trigger earthquakes have been investigated by many authors for more than one century. After summarizing studies ranging among the most prominent ones on the topic, we present an example of statistical results related to tide-earthquakes correlations starting from a database concerning a specific seismic area, the Vrancea fault located in Romania.
Colliding continents
  • M Searle
Searle, M. (2013) Colliding continents, Oxford University press, 433 p.