Earth tide and moonquakes · Observatoire des phénomènes naturels

Correspondences

What is linked, what is not

Each arc joins two phenomena tested on this site. Green and animated: clear link (correlation significant at 5 % after correcting for autocorrelation, or a response outside chance in an event study). Grey: inconclusive test. A statistical link alone does not establish causation.

Clear link
Inconclusive

Hypotheses tested

Clear links

correlation p < 0.05 or epochs outside chance

Causation demonstrated

a correlation demonstrates none

Arc width from |r| of the stored result; several tests between the same phenomena are drawn as stacked arcs.

Hypothesis tested: The Earth deforms the Moon by its tide, the more so as the Moon is close (perigee) and according to its position relative to the Earth’s equator. If this stress triggers the deep moonquakes, each nest should wake at the same phase of the anomalistic month (27.55 d) and of the draconic month (27.21 d). The synodic month (29.53 d), that of the phases and of sunlight, is the control: the Sun does not heat the Moon 900 km down (Lammlein 1977; Bulow et al. 2007).

Nests set by the tide

28 / 28

anomalistic month, p < 0.01 per nest; 28 also by the draconic month; median R 0.94; probability by chance < 10⁻¹⁰

Nests set by the phases

1 / 28

synodic month (control): as many as chance predicts (p = 0.24); median R 0.17

Deep moonquakes tested

955

of the 28 nests with at least 10 quakes, out of 106 located nests

Period analysed

1969-07-27 → 1977-09-30

computed on Oct 26, 2026 · engine v1.0

Nest A1 (186 quakes, 867 km): distribution in the month (%)

Show the data as a table

Share of the quakes of nest A1 per 30° of phase: in the anomalistic month (0° = perigee) they gather in a few bins; in the synodic month (0° = new moon) they spread almost evenly.

The 28 nests tested

Nest	Quakes	Depth (km)	Anomalistic month (R, p)	Draconic month (R, p)	Synodic month (R, p)
A1	186	867	0.60 · < 0,001	0.73 · < 0,001	0.08 · 0.280
A8	68	1,086	0.70 · < 0,001	0.61 · < 0,001	0.25 · 0.013
A9	57	1,037	0.70 · < 0,001	0.98 · < 0,001	0.18 · 0.140
A18	53	925	0.92 · < 0,001	0.79 · < 0,001	0.09 · 0.650
A7	51	893	0.91 · < 0,001	0.81 · < 0,001	0.12 · 0.460
A33 (far side)	49	877	0.97 · < 0,001	0.57 · < 0,001	0.15 · 0.310
A6	41	844	0.89 · < 0,001	0.94 · < 0,001	0.08 · 0.750
A20	41	945	0.50 · < 0,001	0.52 · < 0,001	0.08 · 0.750
A30	34	931	0.76 · < 0,001	0.99 · < 0,001	0.13 · 0.590
A14	32	933	0.97 · < 0,001	0.66 · < 0,001	0.10 · 0.740
A40	30	867	0.97 · < 0,001	0.86 · < 0,001	0.14 · 0.550
A42	30	907	0.81 · < 0,001	0.99 · < 0,001	0.08 · 0.830
A16	29	1,019	0.98 · < 0,001	0.79 · < 0,001	0.13 · 0.640
A5	27	933	0.90 · < 0,001	0.83 · < 0,001	0.36 · 0.031
A39	26	933	0.98 · < 0,001	0.96 · < 0,001	0.15 · 0.560
A21	25	1,037	0.96 · < 0,001	0.89 · < 0,001	0.14 · 0.630
A15	20	747	0.92 · < 0,001	0.72 · < 0,001	0.21 · 0.420
A44	18	908	0.97 · < 0,001	0.97 · < 0,001	0.22 · 0.430
A97	18	989	0.98 · < 0,001	0.97 · < 0,001	0.29 · 0.220
A25	16	924	0.99 · < 0,001	0.95 · < 0,001	0.15 · 0.700
A34	16	971	0.95 · < 0,001	0.99 · < 0,001	0.25 · 0.380
A17	15	807	0.90 · < 0,001	0.99 · < 0,001	0.29 · 0.290
A41	15	847	0.97 · < 0,001	0.97 · < 0,001	0.26 · 0.380
A19	13	974	0.98 · < 0,001	0.94 · < 0,001	0.26 · 0.440
A27	13	1,085	0.94 · < 0,001	0.78 · < 0,001	0.39 · 0.140
A50	11	828	0.94 · < 0,001	0.96 · < 0,001	0.65 · 0.007
A82	11	919	0.98 · < 0,001	0.93 · < 0,001	0.30 · 0.390
A10	10	988	0.77 · 0.001	0.96 · < 0,001	0.23 · 0.590

Aligned series (CSV)

Method and sources

Event catalogue of the Apollo seismic network (levent.1008, Nakamura et al. 1981, updated; PDS Geosciences) and positions of the deep nests (Nakamura 2005). For each deep moonquake assigned to a nest, the phase of the Moon at the onset of the signal is computed in three months: mean anomaly M′ (anomalistic month), argument of latitude F (draconic) and mean elongation D (synodic), after Meeus (1998, eq. 47.2 to 47.5). For each nest of at least 10 quakes, the Rayleigh test measures the clustering of the phases (length R of the mean vector, p after Zar 2010). The number of nests significant at p < 0.01 is compared with the 1 % expected by chance (binomial law, nests assumed independent).

Computation parameters

{
    "test": "Rayleigh test per nest (Zar 2010, eq. 27.4) for nests of at least 10 events; count of nests with p < 0.01 against a binomial(n, 0.01) null",
    "phase": "mean anomaly M′, argument of latitude F and mean elongation D of the Moon at the onset time (Meeus 1998, eq. 47.2–47.5)",
    "control": "synodic month: sunlight and phase, without tidal role at this period",
    "catalogue": "Apollo passive seismic experiment, lunar event list levent.1008 (Nakamura et al. 1981, updated) and deep nest locations (Nakamura 2005), PDS Geosciences Node"
}

Inputs :

Reading this result

The result is clear: every nest tested follows the tide, almost none the phases. This is the proof, known since the 1970s, that the Earth’s tide triggers the deep moonquakes. The preferred phase changes from nest to nest, as each responds to a different component of the tidal stress: phases therefore do not add up across nests, and the test is made nest by nest. Nests are defined by the likeness of their signals, which does not depend on the date. Correlation is not causation: common factors (seasons, cycles, trends) or coincidence can produce it. The p-values account for autocorrelation (effective n) but not for preprocessing choices; the confidence interval comes from a block bootstrap. The limits of the source data apply.

SOURCES OF THIS PAGE

Lammlein (1977): Lammlein, D. R. (1977). Lunar seismicity and tectonics. Physics of the Earth and Planetary Interiors, 14, 224–273. · doi:10.1016/0031-9201(77)90175-3
Licence : Published literature; cited
Bulow et al. (2007): Bulow, R. C., Johnson, C. L., Bills, B. G., & Shearer, P. M. (2007). Temporal and spatial properties of some deep moonquake clusters. JGR Planets, 112, E09003. · doi:10.1029/2006JE002847
Licence : Published literature; cited
Nakamura (2005): Nakamura, Y. (2005). Farside deep moonquakes and deep interior of the Moon. JGR Planets, 110, E01001. · doi:10.1029/2004JE002332
Licence : Published literature; cited

Earth tide and moonquakes The Earth triggers the deep moonquakes

What is linked, what is not