By Apostolos Hatziparaskevaïdis
1. Morphology
Syros in terms of topography holds a fabourable position equally
in the area of the Cyclades, being at the very centre of them, as in the overall
Greek territory, a fact which has significantly contributed -especially before
the opening up of the Corinth isthmus- to its rapid development. It is a small
island of just 84 square kilometers in geographical area but with a coastline
development of 87 kilometres. It is host though to a superb natural harbour of
0.89 sq. km., the main town of the island having been built next to it,
and possesses a particularly interesting relief with small mountains and steep
and abrupt hills, the latter having been utilised ever since antiquity as a
shelter through the creation of fortified settlements (Kastri, Agia Pakou, Ano
Syros etc.). The northern part of the island is mountainous with altitudes
ranging between 300 and 450 metres above sea level and barren; for this reason,
the small rural areas have always had a family character (Kartas, 1982), while
nowadays they are practically in use solely during the summer months, since very
few farmers occupy themselves with the cultivation of the small terraced fields
any more of Epano Meria (literally: ‘the Upper Side’). On the contrary, the
island’s southern part is flat almost in its full extent, with fertile small
valleys where agriculture, blessed by the mild climate of the island, focusing
on early garden produce has been considerably developed.
Syros’network of
residential districts is organised according to these centres of production, and
only in the past decade has a new source of income, namely tourism and the
vacational needs of the locals, contributed to the creation of new
residential development in other coastal areas (M. Yalos, Ambela, Agathopes), or
the continuous expansion towards the sea of already existing districts
(Galissas, Foinikas, Vari, Kini etc.). This relatively one-sided population
concentration –leaving aside of course the main residential block of Ermoupoli
and Ano Syros,- but also the low relief of Southern Syros gave rise to the
progressive construction of a fairly rich road network throughout it, whereas
the northern part as a whole is dependent on one country road connecting Ano
Syros and San Michalis with small branch roads to serve the neighbouring
districts on either side of the road.
2. Geology
Geotectonically speaking, Syros is structured by metamorphic
rocks of the Attico-Cycladic zone.One generally encounters schists of diverse
types and various degrees of metamorphism, gneisses, metamorphic volcanics
(metavolcanics), marbles and quaternary deposits. According to a radioactive age
determination, all Syros' rocks have undergone Eocene epoch high pressure and
temperature metamorphism. At some later stage, some of the formations have
remetamorphosed (green-schist phase). In fact, the extent of metamorphosis is
particularly evident in the southern part of the island, where only rarely are
high pressure and terperature phases to be traced. The age of metamorphism has
been determined to be towards the end of the Oligocene and the start of the
Oligocene epoch. According to the relevant geological map of the Greek Institute
for Geological and Mineral Explorations (Syros issue, scale 1: 50.000), in Syros
there have been traced metamorphic formations of the Attico-Cycladic zone,
covered in some places by alluvial deposits of small thickness and/or their
corrosion mantle. Specifically, one comes across the typical marbles and schists
of the Syros marble-schist series, on which the
‘Cambos-Vaporia-Manna-Charasonas’system of metabasic schists impends through
tectonic contact. In these schists one locates individual metagabbro
appearances, as well as – quite frequently, intensely abrated- serpentinites
(Aranitis, 2004).
3. Tectonics
The above mentioned
formations have undergone, except for the alluvions, also the influence of
powerful tectonic forces, so as to now appear disrupted and intensely folded.
Thrusts, overthrusts, folds, faults and tectonic contacts of all sorts are the
norm as far as the geological structure of the island is concerned and
constitute the causes of its intense vertical and horizontal dissection. The
most important tectonic contact traced in the area of study brings to contact
the upper system of marble, schist, and metavolcanic formations on top of the
main marble-schist system of the island. In proximity to this contact, namely in
the northern part of Ermoupoli (area: Livochori), a landslide has been recorded
with a main view 0f 50 metres.
4. Seismicity
According to the seismological data on towns and residential
districts of the prefecture of the Cyclades put together by the Greek Ministry
for the Environment, Space Planning, and Public Works concerning the seismicity
of various areas, Syros comes under Category I, that is the category for which
the seismological conditions are positive and do not require any further
elaborate research as for the seismological problem. The directions of the main
fault fissues are NW (deviating towards N-NW and W-NW) and NE (with deviations
towards N-NE and E-NE). Apart from these there are also fault fissues whose
direction is almost N-S. All the displacement fault systems appear equally in
the inland and the frame of the
island.
5. Hydrogeology
The hydrological behaviour of the various formations is
codetermined by their lithological composition, and the geotectonic conditions
prevalent in the region. The formation of underground water tables is dependent
on the amount of air deposits and the water permeability of the rocks. In Syros
the annual rainfall amount is very small and ranges up to 600 millimetres. The
rain season in the island lasts from October till March.
6. Climatological data
The climate of Syros is temperate and approximates the sea
climate. It bears resemblance to the climate of the Mediterranean, it indeed has
the qualities of the Mediterranean climate, in which no great differences
between minimum and maximum air temperature are observed. Syros is
well-known for its sweet winters. H long sunshine, the rare incidence of
snowfall and frost and the sweet temperature render the island very favourable
from a climatological perspective. For the account of the meteological data we
have used the evidence collected by the weather station of the Greek National
Meteorological Service (based in Syros, altitude: 35m above sea level) covering
the period 1970-1996 which are representative of the bioclimatic aspects
of our area of interest. In particular, we have examined the monthly rates of
the average, the mean annual maximum and minimum air temperature, the average
relative humidity, the mean total amount of rain precipitation, as well as the
average number of days with partial or total frost, fog, snow and rain
precipitation etc.
Our area of study has in all
the following climatic features:
The annual rainfall amount ranges around 350
millimetres
The days of rainfall are annually about
33
The annual air temperature is 18.7°C
There is low
relative humidity in the period from May-September
The climate in Syros is temperate and there are not observed
many differences between minimum and maximum air temperature values.
Bioclimatically, Syros belongs to the intense warm-Mediterranean type and to the
semi-dry bioclimatic floor with a warm winter in which m>7° C (m=mean minimum
temperature of the coldest month). The bioclimate of the region is semi-dry with
a small excess of water in the winter, midwarm due to the proximity to the sea
it receives its influence in forming its thermal character.
Concerning the vegetation of the area, dryness is not the sole
significant factor. The other factors having an important role to play are the
duration of the dry period and the rainfall-temperature chart of the region,
which is informative of the dry period (the month total that ought to be defined
as dry), the annual range of temperature, the monthly and seasonal rain
allocation and the segregation between dry and wet period.
6.1 Temperature
The coldest months are January and February while the hottest is
July, with average temperatures of 11.8° C and 26.7° C respectively. The
fluctuation of the monthly mean temperature values in addition to the annual
mean and extreme air temperature values (factors of particularly significant
biological value) are presented on the
chart.
6.2 Rainfall
The total amount of rain precipitation in Syros station is 364.7
mm and the maximum 24 hour amount is 92.9 mm and it has been recorded in
October.Generally speaking, the mean annual amount of rainfall in Syros is at
low levels, given that 700mm in additional combination with the temperatures of
each place constitute the border between the semi-dry and the wettish climate
zone. The mean monthly rainfall records its maximum amount level in December and
its minimum in August, while the maximum rain-measuring diet is of the form
WASpS (maximum seasonal rainfall with the first being the season showing the
highest rainfall, where W stands for winter, A for autumn, Sp for spring, S for
summer). Lastly, from the evidence available through the Syros weather station,
it has been observed that fog, hail, and snow are phenomena with a rare
incidence in the region.
6.3. Wind
Winds in the
area of the Syros weather station blow from north (44%), southeast(14,8%),
northeast (12.4%), and south (12.3%) directions. In terms of intensity winds are
light at a rate of 13.2%, moderate at 18.5%, and 11.9% are strong winds. The
percentage of calm amounts to 3.3%. The most prevalent are the winds of
Beaufort 4 followed by winds at Beaufort 5 and Beaufort
3.
6.3 Relative humidity
The average relative humidity in the Syros weather station is
70.5%, the highest value being in November (77.4%), and the minimum in July
(60.3%).
6.4 Nebulosity
It has been observed that overcast days are very rare from June
until October and particularly increased during the winter months.
Copyright fotos : 
Copyright maps: Fr. Caloutas from the
publication “Syra: Historic Memory and Tour”
Protopapadaki 20, Ermoupoli 84100
Syros - tel:+3022810-82577
