Geology The geology of
Croatia has some Precambrian rocks mostly covered by younger sedimentary rocks and deformed or superimposed by tectonic activity. The country is split into two main onshore provinces, a smaller part of the
Pannonian Basin and the Karst Region in the
Dinarides. The carbonate platform karst landscape of Croatia helped to create the weathering conditions to form
bauxite,
gypsum, clay,
amphibolite, granite,
spilite,
gabbro,
diabase and
limestone.
Topography Most of Croatia is lowlands, with elevations of less than above sea level recorded in 53.42% of the country. Most of the lowlands are found in the country's northern regions, especially in
Slavonia, representing a part of the
Pannonian Basin. Areas with elevations of above sea level encompass 25.61% of Croatia's territory, and the areas between above sea level cover 17.11% of the country. A further 3.71% of the land is above sea level, and only 0.15% of Croatia's territory is elevated greater than above sea level.
Adriatic Basin Croatia's Adriatic Sea mainland coast is long, while its
1,246 islands and islets have a further of coastline. The distance between the extreme points of Croatia's coastline is . The number of islands includes all islands, islets, and rocks of all sizes, including ones emerging only at
low tide. The largest islands in the Adriatic are
Cres and
Krk, each covering ; the tallest is
Brač, reaching above sea level. The islands include 47
permanently inhabited ones, the most populous among them being Krk and
Korčula. The shore is the most indented coastline in the Mediterranean. The majority of the coast is characterised by a
karst topography, developed from the
Adriatic Carbonate Platform. Karstification there largely began after the final raising of the
Dinarides in the
Oligocene and
Miocene epochs, when
carbonate rock was exposed to atmospheric effects such as rain; this extended to below the present sea level, exposed during the
Last Glacial Maximum's sea level drop. It is estimated that some karst formations are related to earlier drops of sea level, most notably the
Messinian salinity crisis. The eastern coast's largest part consists of carbonate rocks, while
flysch rock is significantly represented in the Gulf of Trieste coast, on the
Kvarner Gulf coast opposite Krk, and in Dalmatia north of Split. There are comparably small
alluvial areas of the Adriatic coast in Croatia—most notably the
Neretva river delta. Western
Istria is gradually subsiding, having sunk about in the past 2,000 years. In the Middle Adriatic Basin, there is evidence of
Permian volcanism in the area of
Komiža on the island of
Vis, in addition to the volcanic islands of
Jabuka and
Brusnik. Earthquakes are frequent in the area around the Adriatic Sea, although most are too faint to be felt; an earthquake doing significant damage happens every few decades, with major earthquakes every few centuries.
Dinaric Alps The Dinaric Alps are linked to a Late
Jurassic to recent times
fold and thrust belt, itself part of the
Alpine orogeny, extending southeast from the southern
Alps. The Dinaric Alps in Croatia encompass the entire Gorski Kotar and Lika regions, as well as considerable parts of
Dalmatia, with their northeastern edge running from
Žumberak to the
Banovina region, along the Sava River, and their westernmost landforms being
Ćićarija and
Učka mountains in Istria. The Dinaric Alps contain the highest mountain in Croatia—
Dinara—as well as all other mountains in Croatia higher than :
Biokovo,
Velebit,
Plješivica,
Velika Kapela,
Risnjak,
Svilaja and
Snježnik. There are
numerous caves in Croatia, 49 of which are deeper than , 14 deeper than and 3 deeper than . The longest cave in Croatia,
Kita Gaćešina, is at the same time the longest cave in the Dinaric Alps at . , highest point of Croatia (1,831 m)|alt=Picture of large mountain with about 30-degree sloped sides
Pannonian Basin The Pannonian Basin took shape through Miocenian thinning and
subsidence of crust structures formed during the Late
Paleozoic Variscan orogeny. The Paleozoic and
Mesozoic structures are visible in
Papuk and other Slavonian mountains. The processes also led to the formation of a
stratovolcanic chain in the basin 12–17
Mya; intensified subsidence was observed until 5 Mya as well as
flood basalts at about 7.5 Mya. The contemporary
tectonic uplift of the
Carpathian Mountains severed water flow to the
Black Sea and the
Pannonian Sea formed in the basin.
Sediments were transported to the basin from the uplifting Carpathian and Dinaric mountains, with particularly deep
fluvial sediments being deposited in the
Pleistocene epoch during the
Transdanubian Mountains' formation. Ultimately, up to of sediment was deposited in the basin, and the sea eventually drained through the
Iron Gate gorge. The results are large plains in the area bound by the rivers of Danube,
Sava, Drava, and
Kupa (including Slavonia,
Baranya, and
Syrmia). The plains are interspersed by isolated mountains. The tallest among such landforms are
Ivanšćica and
Medvednica north of
Zagreb—both are also at least partially in
Hrvatsko Zagorje—as well as
Psunj and Papuk that are the tallest among the Slavonian mountains surrounding
Požega. The two, as well as the
Moslavačka gora mountains, are possibly remnants of a
volcanic arc from the same
tectonic plate collision that caused the Dinaric Alps. The longest rivers in Croatia are the Sava, Drava, Kupa and a section of the Danube. The longest rivers emptying into the Adriatic Sea are the
Cetina and an only section of the Neretva.
Climate , a
UNESCO World Heritage Site|alt=Two greenish-blue lakes in a forest Most of Croatia has a moderately warm and rainy
subtropical highland climate (Cfb) as defined by the
Köppen climate classification. The northern Adriatic coast and islands, as well as the Dalmatian coast's
hinterland are characterised by the
warm temperate climate (Cfa) climate and most of the central and southern Adriatic coast and islands have the
Mediterranean climate (mostly Csb) climate. The highest elevations are characterised by the Df climate. Mean monthly temperatures range between and in the coldest month (January) except in the coldest parts of the country are Lika and Gorski Kotar at elevations above where that metric is lower. Temperature peaks are more pronounced in the continental areas: the lowest temperature of was recorded on 3 February 1919 in
Čakovec, and the highest temperature of was recorded on 5 July 1950 in
Karlovac. The mean annual precipitation is depending on the geographic region and prevailing climate type. The least precipitation is recorded in the outer islands (Vis,
Lastovo,
Biševo, and
Svetac) and in the eastern parts of Slavonia; however, in the latter case the precipitation mostly occurs during the
growing season. The prevailing winds in the interior are light to moderate northeast or southwest. Higher wind velocities are more often recorded in cooler months along the coast, generally as cool northeasterly
bora (sometimes exceeding and southerly
sirocco. The sunniest parts of the country are the outer islands, Hvar and Korčula, where more than 2,700 hours of sunshine are recorded per year, followed by the southern Adriatic Sea area in general, northern Adriatic coast, and Slavonia, all with more than 2,000 hours of sunshine per year. Among the most significant are
karst habitats; these include submerged karst, such as
Zrmanja and
Krka canyons and
tufa barriers, as well as underground habitats. The karst geology has produced approximately 7,000 caves and pits, many of which are inhabited by
troglobitic (exclusively cave-dwelling) animals such as the
olm, a
cave salamander and the only European troglobitic
vertebrate. Forests are also significant in the country, as they cover representing 46.8% of Croatia's land surface. In terms of
phytogeography, Croatia is part of the
Boreal Kingdom; specifically, it is part of the Illyrian and Central European provinces of the
Circumboreal Region and the Adriatic province of the
Mediterranean Region. The
World Wide Fund for Nature divides land in Croatia into three ecoregions—
Pannonian mixed forests,
Dinaric Mountains mixed forests and
Illyrian deciduous forests.
Biomes in Croatia include
temperate broadleaf/mixed forest and
Mediterranean forests, woodlands and scrub; all are in the
Palearctic realm. in
Krka National Park |alt=Vertically cracked grey rock Croatia has 38,226 known
taxa, 2.8% of which are
endemic; the actual number (including undiscovered
species) is estimated to be between 50,000 and 100,000.
Ecology landfill, used for
Zagreb's solid waste disposal The
ecological footprint of Croatia's population and industry varies significantly between the country's regions since 50% of the population resides in 26.8% of the nation's territory, with a particularly high impact made by the city of Zagreb and Zagreb County areas—their combined area comprises 6.6% of Croatia's territory while encompassing 25% of the population. The ecological footprint is most notably from the increased development of settlements and the sea coast leading to
habitat fragmentation. Between 1998 and 2008, the greatest changes of
land use pertained to artificially developed areas, but the scale of development is negligible compared to EU member states. The Croatian Environment Agency (CEA), a public institution established by the
Government of Croatia to collect and analyse information on the environment, has identified further ecological problems as well as various degrees of progress in terms of curbing their environmental impact. These problems include inadequate legal
landfills as well as the presence of illegal landfills; between 2005 and 2008, 62 authorised and 423 illegal landfills were
rehabilitated. In the same period, the number of issued
waste management licences doubled, while the annual
municipal solid waste volume increased by 23%, reaching per capita. The processes of
soil acidification and
organic matter degradation are present throughout Croatia, with increasing
soil salinity levels in the
Neretva river plain and spreading areas of
alkali soil in
Slavonia. of land remain suspected of containing land mines in 2025.
Regions Croatia is traditionally divided into numerous, often overlapping geographic regions, whose borders are not always clearly defined. The largest and most readily recognisable ones throughout the country are
Central Croatia (also described as the Zagreb macro-region), Eastern Croatia (largely corresponding with Slavonia), and
Mountainous Croatia (Lika and Gorski Kotar; to the west of Central Croatia). These three comprise the inland or continental part of Croatia. Coastal Croatia consists of a further two regions: Dalmatia or the southern littoral, between the general area of the city of
Zadar and the southernmost tip of the country; and the northern littoral located north of Dalmatia, encompassing the
Croatian Littoral and Istria. The geographical regions generally do not conform to county boundaries or other administrative divisions, and all of them encompass further, more specific, geographic regions. ==Human geography==