lie the Marmara Islands, an archipelago made up of the eponymous Marmara Island and three other inhabited islands – Avşa, Paşalimanı and Ekinlik – as well as of seventeen largely uninhabited islands including the prison island of Imralı whose most famous prisoner, since 1999, has been the PKK leader Abdullah Öcalan. These islands lie within Balıkesir province and are most readily accessible from Tekirdağ in Thrace or Erdek on the southern shore of the Sea of Marmara. In high summer additional ferries travel to Avşa and Marmara Islands from the centre of İstanbul to facilitate a growing tourist trade. There are also a few individual islands elsewhere in the Sea of Marmara, such as Koç Adası, off Tuzla, which is privately owned by the Koç family of industrialists. Problems facing the Sea of Marmara The North Anatolian Fault runs under the sea and has triggered several major earthquakes, such as those in Izmit and Düzce in August and November 1999 respectively. The August 1999 earthquake is commonly referred to as the Marmara Earthquake since its epicentre lay under the Sea and most of the places worst affected by the quake and ensuing tsunami lay along its shores. During a storm on 29 December 1999, the Russian oil tanker Volgoneft broke in two in the Sea of Marmara, spilling more than 1,500 tonnes of oil into the water. In 2021 the shores of the Sea of Marmara were disfigured by mucilage - nicknamed 'sea snot' - caused, at least in part, by the dumping of untreated waste into the water. Extent The International Hydrographic Organization defines the limits of the Sea of Marmara as follows: On the West. The Dardanelles limit of the Aegean Sea [A line joining Kum Kale (26°11'E) and Cape Helles]. On the Northeast. A line joining Cape Rumili with Cape Anatoli (41°13′N). Towns and cities Towns and cities on the coast of the Sea of Marmara include: Gallery See also 1509 Constantinople earthquake 1999 İzmit earthquake Black Sea deluge hypothesis Kanal İstanbul Montreux Convention Regarding the Regime of the Straits Turkish Straits Notes References External links "Sea of Marmara" at the Encyclopædia Britannica "Sea of Marmara: Where Ancient Myth and Modern Science Mix" at SCIENCE FOCUS – SeaWiFS Ancient Greek geography Marmara Marmara Marmara Region Geography of Southern Europe Geography of Western Asia Landforms of Istanbul Province Landforms of Balıkesir Province Landforms of Bursa Province Landforms of