CHAPTER XIV._Earthquakes and other earth movements

DISTRIBUTION OF EARTHQUAKES IN TIME (_continued_).

The occurrence of earthquakes in relation to the position of the

heavenly bodies—Earthquakes and the moon—Earthquakes and the sun;

and the seasons; the months—Planets and meteors—Hours at which

earthquakes are frequent—Earthquakes and sun spots—Earthquakes

and the aurora.

_The position of the heavenly bodies and the occurrence of

earthquakes._—Since the earliest times, in searching for the cause of

various natural phenomena, man has turned his energies towards the

heavens. One of the earliest observations was the connection that

exists between the season of the year and the motions of the heavenly

bodies. Tides were seen to be influenced by the moon. In later times

it has been discovered that periods of maximum magnetic disturbances

occur every ten or eleven years with the sun spots, and Herr Kreil, of

Vienna, tells us our satellite, the moon, has also an influence upon

the magnet.

From day to day we see the bond connecting our planet with the sun, the

moon, and other heavenly bodies which are outside us gradually becoming

closer.

Inasmuch as many phenomena, like the motion of the tides, the rise and

fall of the barometer, fluctuations in temperature, are all more or

less directly connected with the relative position of our planet with

regard to the sun and moon, any coincidence between the phases of

these bodies and the occurrence of earthquakes more or less involves a

time relationship with the other phenomena resultant on lunar and solar

influences.

_Earthquakes and the position of the moon._—Many earthquake

investigators have attempted to show the connection between earthquakes

and the phases of the moon.

The first and most successful worker in this branch of seismology was

Professor Alexis Perrey, of Dijon, who, after many years of arduous

labour in tabulating and examining catalogues of earthquakes, showed

that earthquakes were more likely to occur at the following periods

than at others.

1. They are more frequent at new or full moon (syzygies) than at half

moon (quadratures).

2. They are more frequent when the moon is nearest the earth (perigee)

than when she is farthest off (apogee).

3. They are more frequent when the moon is on the meridian than when

she is on the horizon.

These results were obtained by Perrey after analysing his catalogues

by three different and independent methods, and they were confirmed

by the report of a committee appointed by the Academy of Sciences. It

must, however, be remarked that in several instances anomalies occur,

and also that the difference between the number of earthquakes at any

two periods is not a very large one. Thus, for instance, the annual

catalogues compiled by Perrey from 1844 to 1847, the earthquakes in

perigee are to those in apogee as 47 : 39. Between the years 1843 and

1872 Perrey finds that 3,290 shocks occurred at the moon’s perigee, and

3,015 at the apogee.[99]

Between 1761 and 1800 earthquakes occurred as follows:—

In Perigee 526

Apogee 465

The following table shows the results which enabled Perrey to deduce

his first law.

Dividing the period of lunation into quarters, with the time of

syzygies and quadratures as the centres of these quarters, he found

that the earthquakes were distributed as follows.

+-----------+--------+----------+-------------+---------------+

+-----------+--------+----------+-------------+---------------+

| 1843–1847 | 1,604 | 850·48 | 753·52 | 69·96 |

| 1848–1852 | 2,049 | 1,053·53 | 995·47 | 58·06 |

| 1853–1857 | 3,018 | 1,534·13 | 1,483·87 | 50·26 |

| 1858–1862 | 3,140 | 1,602·99 | 1,537·41 | 65·98 |

| 1863–1867 | 2,845 | 1,463·42 | 1,381·58 | 81·84 |

| 1868–1872 | 4,593 | 2,333·48 | 2,259·52 | 73·96 |

| 1843–1872 | 17,249 | 8,838·03 | 8,410·97 | 427·06 |

+-----------+--------+----------+-------------+---------------+

The reported earthquakes between 1751 and 1843 are shown to conform

with the same rule.[100] Julius Schmidt, astronomer at Athens, found

for the earthquakes of Eastern Europe and adjacent countries for the

years 1776 to 1873 that there were more earthquakes when the moon was

in perigee. Other maxima were at new moon, and two days after the first

quarter. There was a diminution at full moon, and a minimum on the day

of the last quarter. As one example of results which are antagonistic

to the general results obtained by Perrey may be quoted the results of

an examination by Professor W. S. Chaplin of the earthquake recorded at

the meteorological observatory in Tokio. The list of earthquakes, 143

in number, extending over a period of three years, was recorded by one

of Palmieri’s instruments. The results were as follows:—

1. There have been maxima of earthquakes when the moon was two and

nine hours east and seven hours west. At the upper transit there is a

minimum.

2. Considering the moon’s position with regard to the sun, at

conjunction there were 32, at opposition 37, and at quadrature 74. East

of the meridian the maximum was at least four hours.

3. When the moon was north of the equator these were 68, when south 82.

4. A maximum of earthquakes seven and eleven days after the moon’s

perigee. The fact that these results were obtained for the earthquakes

of a special small seismic area renders them more interesting.[101]

_Frequency of earthquakes in relation to the position of the sun._—The

question as to whether there is a connection between the frequency of

earthquakes and the relative position of the sun is to a great extent

identical with the question as to the relative frequency of earthquakes

in the various seasons. It is a subject which we find referred to

by writers in the earliest ages. Pliny and Aristotle thought that

earthquakes occurred chiefly in spring and autumn. In later times it

has been a subject which has been most carefully considered by Merian,

von Hoff, Perrey, Mallet, Volger, Kluge, and others who have devoted

attention to seismology. In a résumé of the earthquakes of Europe, and

of the adjacent parts of Asia and Africa, from A.D. 306–1843, Mallet

gives the following results:—

+------------------+------------------------+----------------------+

| | For Nineteenth Century | For the whole period |

+------------------+------------------------+----------------------+

| Winter Solstice | 177 } Solstices | 253 } Solstices |

| Spring Equinox | 151 } } 306 | 170 } } 403 |

| Summer Solstice | 129 } } Equinoxes | 150 } } Equinoxes |

| Autumnal Equinox | 164 } 315 | 159 } 329 |

+------------------+------------------------+----------------------|

The above periods were called by Perrey _critical epochs_, because

as a general result of his researches he found that at such periods

there was a greater frequency of earthquakes. Fuchs, quoting from

Kluge’s tables, extending from 1850–1857, tells us that the recorded

earthquakes occurred as follows:—

In the Northern Hemisphere—

Equinoxes =1324=

Solstices 1202

In the Southern Hemisphere—

Equinoxes =301=

Solstices 261

Earthquakes are, therefore, more frequent at the equinoxes, and this

especially at the autumnal equinox. In the northern hemisphere, at

the solstices, the greater number of shocks occur about the winter

solstices, whilst in the southern hemisphere, about the summer

solstices.

Exceptions, however, are found in Central America and the West Indies,

in the Caucasus, and the Ægean Sea.

The idea that earthquakes had a periodicity dependent upon the position

of the heavenly bodies is by no means confined to Europe. In a Japanese

work called ‘Jishin Setsu’ (an opinion about earthquakes) by a priest

called Tensho, it is stated that the relative positions and movements

of the twenty-eight constellations with respect to the moon cause

earthquakes. This Tensho asserts after careful calculation, and Falb

tells us that all future earthquakes can be predicted.

In the Kuriles and Kamschatka, Sicily, and in parts of South America,

it is said that the equinoxes are regarded as dangerous seasons.

_Frequency of earthquakes in relation to the seasons and months._—What

is here said respecting the relative frequency of earthquakes at the

different seasons and months is little more than an extension and

critical examination of the results which have been given respecting

the frequency of earthquakes in regard to the position of the sun.

That there is a difference between the number of earthquakes which are

felt at one season of the year as compared with those felt at another

is a fact which, as seismoscopic observations are extended, is becoming

more and more recognised.

Some of the more important results which were arrived at by Mallet from

5,879 observations made in the northern hemisphere, and 223 in the

southern hemisphere, may be expressed as follows:—

+---------------------+------------------------+-------------------+

| | Maxima | Minima |

+---------------------+------------------------+-------------------+

| Northern Hemisphere | January, also a slight | May, June, and |

| | rise in August and | July |

| | October | |

| Southern Hemisphere | November, also May | March, extending |

| | and June | over one month, |

| | | also August |

+---------------------+------------------------+-------------------+

Julius Schmidt, of Athens, who so carefully examined the earthquakes of

eastern Europe, came to the following conclusions:—

For the earthquakes between 1200 and 1873, a maximum on September 26

and January 17; a minimum on December 3 and June 13.

For the earthquakes between 1873 and 1874, a maximum on March 1 and

October 1; a minimum on July 7 and December 15.

For all the earthquakes of eastern Europe, a maximum on January 3; a

minimum on July 8, or there was a maximum at perihelion and aphelion.

When the months are grouped together according to the seasons, spring,

summer, autumn, and winter, we find that in the northern hemisphere the

minimum is in summer and the maximum in winter, whilst in the southern

hemisphere (giving the proper months corresponding to its seasons) we

find two maxima, one at the commencement of winter, and the other at

midsummer, whilst the minima are in spring and autumn.

[Illustration: FIG. 36.—Curves of Monthly Seismic Intensity (Mallet).]

In the following table the difference in the number of earthquakes felt

at different seasons is given more in detail.

In examining this table, we must remember that for countries like Peru,

Chili, and New Zealand, lying in the southern hemisphere, the records

given for the months April to September correspond to the winter months

of those countries. The Roman numerals indicate the centuries between

which the records date.

+----------+----------------------------------------+-------+---------+

| | | to | to |

+----------+----------------------------------------+-------+---------+

| {| 1. Scandinavia and Iceland, xii–xix | =129= | 91 |

| {| 2. British and Northern Isles, xi–xix | =123= | 94 |

| {| 3. Belgium, France, and Holland, iv–xix| =395= | 272 |

| {| 4. Rhone Basin, xvi–xix | =115= | 69 |

| {| 5. Switzerland and Rhine Basin, ix–xix | =327= | 205 |

| {| 6. Danube Basin, v–xix | =147= | 128 |

| {| 7. Spanish Peninsula, xi–xiv | =114= | 87 |

| {| 8. Italy, Sicily, Sardinia, and Malta, | | |

|Northern {| iv–xix | 650 | 581 |

| Regions {| 9. Turco-Hellenic Territory, Syria, | | |

| {| Ægean Isles, and Levant, iv–xix | 214 | =222= |

| {|10. Northern Zone of Asia, xviii–xix | =46= | 36 |

| {|11. Japan (Tokio area), 1872–1880 | | |

| {| (small earthquakes) | =213= | 157 |

| {|12. Japan B.C. 295-A.D. 1872 (large | | |

| {| earthquakes) | 165 | =188= |

| {|13. Algeria and Northern Africa | =26= | 20 |

| {|14. United States and Canada, xvii–xix | =86= | 48 |

| { |15. Java, Sumatra, and neighbouring | | |

| { | Islands, 1873–4–7–8 | =194= | 182 |

|Central { |16. Mexico and Central America, xvi–xix | 26 | 26 |

|Regions { |17. West Indies (Mallet), xvi–xix | 108 | =114= |

| { |18. West Indies, xvi–xix | 296 | =343= |

| { |19. Cuba, xvi–xix | =28= | 23 |

| {|20. Chili, and La Plata Basin, xvi–xix | 89 | 89 |

|Southern {|21. Peru, Columbia, Basin of Amazons, | | |

|Regions {| xvi–xix | 506 | =541= |

| {|22. New Zealand, 1869–1879 | 166 | =176= |

+----------+----------------------------------------+-------+---------+

Neglecting those records which show as many earthquakes for the winter

months as for the summer months, we see at a glance that generally

the greater number of shocks have happened during the colder seasons.

In the southern hemisphere, so far as the records go, this is not

true. In the northern regions, out of fourteen examples there are

two exceptions. In the central regions there are two cases where the

greatest number of earthquakes have been recorded in the winter months,

and two cases where the greatest number have been recorded for the

summer.

Altogether, out of twenty-two examples, there are only six exceptions

to the rule. These exceptions altogether occur among records many of

which are ancient, and are, therefore, more open to error than lists

which have been compiled in modern times.

Because small earthquakes are seldom noticed by persons out in the

open air, it might be expected that the number of earthquakes observed

in warm countries at one portion of the year would be equal to those

observed in any other season. Such an argument, however, would hardly

apply to most of the records which are quoted, as they refer to

destructive disturbances.

If, however, we take the records made in tropical countries from the

table just given, we see that in such countries there have been almost

as many observations of earthquakes at one season as at any other.

Another fact which might be adduced against the rule that the

greater number of earthquakes occur during the winter months would

be the comparison of a table of earthquakes recorded previous to the

nineteenth century. By doing this we see that for certain countries the

winter rule is inverted, and that the greater number of shocks are felt

during the summer.

Notwithstanding these objections to Perrey’s conclusions, the balance

of evidence is in favour of his general result, and we may conclude

that during the colder portions of the year we may expect more shakings

than during the warmer portions. Comparing the number of earthquakes of

winter and autumn to those of summer and spring, they are to each other

in the proportion of 4 : 3.

A fairer way to examine this question, and to determine what is

probably the present state of seismic activity in our globe, would

be only to consider the earthquakes which have taken place in

comparatively recent times, laying especial stress upon those

observations which have been made with the assistance of automatic

instruments, or those which have been collected by persons interested

in these investigations.

For this purpose the following table, showing the distribution of

earthquakes in different countries during the nineteenth century, has

been compiled.

The arrangement is mensual. Where the number of earthquakes in any

month is above the average, the number is printed in large type; where

below the average, in small type.

EARTHQUAKES OF THE NINETEENTH CENTURY, CHIEFLY FROM PERREY.

Key:

Jan January

Feb February

Mar March

Apr April

May May

Jun June

Jul July

Aug August

Sep September

Oct October

Nov November

Dec December

Ave Average per month

+------------------------------------------------------------------------------+

| |Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec|Ave |

|-------------------------+---+---+---+---+---+---+---+---+---+---+---+---+----|

|Scandinavia and Iceland | 17| 11| 11| 7| 7| 6| 8| 8| 10| 10| 11| 6| 9·3|

| Northern Isles | 9| 9| 10| 7| 8| 6| 5| 11| 12| 8| 11| 12| 9 |

|France, Belgium, Holland | 27| 17| 21| 13| 13| 8| 15| 17| 15| 17| 21| 25|17 |

|Basin of the Rhone | 12| 12| 8| 3| 3| 2| 2| 4| 6| 6| 8| 14| 6·6|

| Switzerland | 15| 17| 13| 12| 11| 6| 12| 11| 10| 17| 24| 25|14 |

|Basin of the Danube | 14| 15| 9| 8| 12| 8| 16| 11| 11| 16| 10| 12|11·8|

|Spanish Peninsula | 10| 5| 6| 7| 4| 6| 10| 5| 9| 11| 7| 5| 7 |

| and Malta | 44| 44| 48| 43| 40| 34| 41| 46| 27| 45| 26| 39|39 |

| and Levant | 22| 20| 10| 10| 16| 15| 14| 22| 14| 17| 12| 14|16 |

|Northern Zone of Asia | 4| 6| 6| 4| 4| 3| 5| 7| 6| 3| 4| 5| 4·7|

| area) | 39| 41| 41| 30| 33| 30| 27| 21| 10| 28| 34| 43|31·4|

|Japan (large earthquakes)| --| 5| 3| 3| 1| --| 5| 4| --| --| 1| 5| 2 |

| Africa | 5| 2| 6| 7| 3| 2| 2| 5| 1| 4| 8| 1| 3·8|

|United States and Canada | 4| 4| 3| 3| 3| --| 4| 6| 3| 2| 7| 5| 3·8|

| 1873–4–5–7 and 9 | 35| 30| 38| 33| 22| 36| 27| 40| 24| 35| 30| 26|31 |

| America | 3| 2| 2| 2| 6| 2| 2| 1| 1| 3| 2| 3| 2·5|

|Antilles | 9| 8| 19| 12| 12| 10| 9| 16| 12| 10| 13| 12|11·8|

|Cuba | 4| 3| 2| 3| 3| 4| 5| 2| 6| 5| 6| 4| 4 |

|Chili and La Plata | 14| 10| 14| 8| 19| 11| 16| 15| 16| 9| 27| 8|13·9|

| of Amazons, xvi–xix | 92| 83| 92| 27|106| 79| 94| 93| 97| 77| 72| 90|87 |

|New Zealand, 1869–79 | 31| 27| 37| 23| 22| 31| 27| 36| 37| 21| 27| 23|28·5|

|Northern Hemisphere |153|162|143|161|126|124|141|156|154|171|151|168|150 |

|Southern Hemisphere | 75| 43| 61| 66| 46| 42| 53| 39| 54| 55| 57| 46|53 |

| 1821–1830 | | | | | | | | | | | | | |

|Northern Hemisphere | 31| 36| 31| 29| 33| 33| 20| 31| 24| 41| 26| 34|30 |

|Southern Hemisphere | 2| --| 1| 1| 3| 1| 3| 2| 3| 2| 1| 1| 1·6|

+-------------------------+---+---+---+---+---+---+---+---+---+---+---+---+----+

A glance at this table shows that for most countries in the northern

hemisphere the rule that there are generally more earthquakes during

the winter months—that is, from October to March—holds good. For

countries which lie comparatively near to the Equator, and also for

those countries in the southern hemisphere, the rule is not so clear.

When examining this table it must be remembered that it does not enable

us to judge of the relative frequency of earthquakes in different

countries, inasmuch as the periods over which the records were taken

are different in different cases.

To the above table might be added the records of P. Merian, who

examined the earthquakes felt in Basle up to 1831. As a result he

found that during the winter months eighty shocks had been felt,

whilst during the summer only forty. Taking the records for the two

hemispheres from 1850–1857, compiled by Kluge,[102] in the northern

hemisphere we have in the months between October and March 948 shocks

against 862 in the remainder of the year. In the same months in the

southern hemisphere we have for the corresponding periods the numbers

337 and 300, and thus both hemispheres would appear to follow the same

rule. If, however, we examine the table we see that the two seasons

are not so pronounced for the southern hemisphere as they are for

the northern, and that there may be two or three periods of maximum

disturbance as has been previously indicated.

_Earthquakes and the planets and meteors._—Just as the moon and the sun

may exert an attractive influence upon the earth and cause earthquakes

to predominate at certain seasons rather than at others, several

investigators of seismic phenomena have thought that the planets might

act in a similar manner.

M. J. Delauney, from a study of Perrey’s tables of earthquakes from

1750–1842, found two groups of maxima each with a period of about

twelve years, one commencing in 1759 and the other in 1756. Two

other groups with twenty-eight year periods respectively commence in

1756 and 1773. These groups coincide with the times when Jupiter and

Saturn reach the mean longitudes of 265° and 135°. From this Delauney

concludes that earthquakes have a maximum when the planets are in the

mean longitudes just mentioned.

The increased number of earthquakes, especially in November, are

attributed to the passage of the earth through swarms of meteors, and

in like manner supposes the influence of Jupiter and Saturn to be due

to their passing through meteor streams situated in mean longitudes

135° and 265°.

As a consequence of this he predicts an increase of earthquakes in the

years 1886, 1891, 1898, 1900, &c.[103]

Dr. E. Naumann, who critically examined the large earthquakes of Japan,

showed that there was an approximate coincidence between many of the

disturbances and the thirty-three year period of meteoric showers.[104]

Humboldt states that a great shower of meteors was seen at Quito before

the great earthquake of Riobamba (Feb. 4, 1797). The earthquakes of

1766 and 1799 at Cumana are also said to have been accompanied with

meteoric showers. Mallet gives a list of large earthquakes which

occurred at the times when meteors were observed.[105]

_The hours at which earthquakes are most frequent._—From the

examination of a catalogue of over 2,000 earthquakes which occurred in

various parts of the world between the years 1850 and 1857, made by

Kluge, it is found that both for the northern and southern hemispheres

the observations which were made during the night generally exceed

those which were made during the day.

+---------------------------+-----------------------+

| | Number of Earthquakes |

+---------------------------+-----------------------+

| | Day | Night |

|In the Northern Hemisphere | 938 | 1592 |

|In the Southern Hemisphere | 292 | 357 |

+---------------------------+---------+-------------+

In the northern hemisphere the greatest number were observed between

10 P.M. and 12 P.M. (360 shocks), and the fewest between 12 and 2 P.M.

(139 shocks). In the southern hemisphere, the greatest number were

observed at night between 12 and 1, and the smallest number between 1

and 2 and 4 and 5 in the afternoon.[106] These distinctions, however,

are less distinctly marked as we approach the Equator. Schmidt found

for the earthquakes of the Orient between 1774 and 1873, that shocks

had been most frequent about half-past two A.M., and less frequent

about 1 P.M. With regard to these conclusions, which have been reached

with much labour, we might be inclined to think that they are partially

to be explained on the supposition that more observations are made

during the night than during the day—the personal experience of

residents in an earthquake country being, that many earthquakes which

occur during the day are passed by unnoticed, whilst those which occur

during the night are recorded by thousands of observers. Such a view is

certainly confirmed by the instrumental records obtained in Japan. From

1872 to 1880 inclusive there were 261 shocks recorded, 132 of which

occurred between the hours of 6 P.M. and 6 A.M.

_Earthquakes and sun spots._—Of late years considerable attention

has been drawn to a coincidence between the occurrence of sun spots,

magnetic disturbances, rainfall, and other natural phenomena.

These periods of sun spots occur about every eleven years, and appear

to be coincident with the periodical return of the planet Jupiter. In

Japan, Dr. E. Naumann sought for a coincidence between these periods of

sun spots and earthquakes, but without any marked results.

Schmidt, who carefully compared his lists of earthquakes with the

appearance of sun spots, came to the conclusion that there was no

marked coincidence. The occurrence of earthquakes had sometimes

synchronised with sun spots, whilst at other times there had been a

maximum of sun spots and no earthquakes.

M. R. Wolf[107] apparently considers that earthquakes, like volcanic

eruptions and the appearance of the aurora, are coincident with sun

spots.

Kluge, however, came to the conclusion that when there are few sun

spots, earthquakes, like volcanic eruptions and magnetic disturbances,

have been at a maximum.

M. A. Poey, who examined a catalogue of the earthquakes of Mexico

and the Antilles, extending from 1634 to 1870, shows by a table that

earthquakes have come in groups, first at the maxima and then at the

minima period of sun spots. Out of thirty-eight groups, seventeen

being at the maximum and seventeen at the minimum, the remaining four

are exceptions to the rule, being between the maximum and minimum.

Phenomena which are dependent upon heat occur with the minima of sun

spots, and those dependent upon cold with the maxima.[108]

_Earthquakes and the aurora._—The possible connection between

earthquakes and the aurora is a subject which has attracted some

attention. Boué has especially made a careful examination of this

subject.[109]

He comes to the conclusion that if we compare the monthly periods of

earthquake frequency and the aurora there is an agreement between

the two. Comparing Perrey’s tables of earthquakes from the fourth to

the nineteenth century, with tables of the aurora, one-third of both

phenomena have occurred, not only in the same day, but often at the

same hour. Between 1834 and 1847, 457 earthquakes are given and 351

notices of the aurora.

Out of these:—

48 occur on the same day,

5 occur in the same hour,

30 approximate to the same time.

The nearer together that these phenomena have occurred the stronger

have they been.

Professor M. S. di Rossi brings forward many examples where there

has been a coincidence between the appearance of the aurora and

earthquakes. On 139 nights out of 211 days the aurora was seen in

some parts of Italy, and ninety-three times earthquakes were felt. On

forty-six occasions earthquakes and aurora took place together.[110] In

considering the probability of a connection existing between these two

phenomena, we must bear in mind that the aurora is at no great height

above the surface of our earth, and, further, that it can be partially

imitated. The fact that in earthquake countries, like Japan, the aurora

is practically never seen, would indicate that we can neither regard

this imperfectly understood phenomenon either as an effect or cause

of earthquakes. That earthquakes and the appearance of the aurora in

certain countries should not sometimes coincide is an impossibility.

Dr. Stukeley, who, it must be remembered, attempted to correlate

the phenomena of earthquakes and electricity, when writing of the

disturbances which shook England in 1849 and 1850, says that the

weather had been unusually warm, the aurora borealis frequent and of

unusually bright colours, whilst the whole year was remarkable for its

fire-balls, lightnings, and corruscations.[111]

The aurora was observed before the commencement of the Maestricht

earthquakes in 1751[112]; whilst at the time of the shock flashes of

light like lightning were observed in the sky.

Glimmering lights were seen in the sky before the New England

earthquakes (Nov. 18, 1755), and again, before the disturbances which

occurred in the same region in 1727, peculiar flashes of light were

seen.

Preceding the Sicilian earthquake of 1692 strange lights were seen

in the sky. Ignis fatui have also been observed with earthquakes. At

the time of auroral displays Bertelli has observed microseismical

disturbances, and M. S. di Rossi, who has made similar observations,

thinks that there is an intimate connection between the aurora and

earthquakes; the aurora either occurring in a period of earthquakes, or

else taking the place of earthquakes.