An intermodal humanitarian logistics model based on maritime transportation for relief item distribution in Istanbul

İstanbul is the most populated city and economic capital of Turkey and it is highly prone to earthquakes. In case of an earthquake, relief items will be supplied from national and international sources. Previous studies have not considered Bosporus strait which divides the city in two sides and the opportunities of maritime transportation for relief item distribution in İstanbul. In this study, an intermodal relief item distribution model for İstanbul involving sea and land transportation with vulnerabilities is proposed to alleviate the suffering of people in case of an earthquake. The proposed mathematical model utilizes efficiently seaports of İstanbul and maritime transportation, and it allows relief item transportation between the European and Anatolian sides. Sea-basing concept is also used for providing supply to the demand areas. Nationally - and internationally- supplied relief items are transported from the supply points (i.e., Port of Haydarpaşa, Port of Ambarlı, and a container ship located at the Sea of Marmara) to the demand areas (i.e., to the districts of İstanbul) directly by utilizing highways. Alternatively, relief items are transported firstly by maritime transportation to the seaports of İstanbul, and then, from the seaports to the districts by highways. Different scenarios based on the available amounts at the supply points are run, and the results are examined in terms of three performance measures: (1) average transportation time per unit relief item, (2) maritime transportation percentage, and (3) the number of ships used to transport relief items. Furthermore, an analysis on supply distribution proportions for the European and Anatolian sides is conducted and a comparison is done with an alternative relief distribution model which utilizes only land transportation. It is seen that benefiting from maritime transportation and sea-basing provides flexibility for humanitarian logistics activities, and the model proposed leads to an effective and reliable disaster relief system for İstanbul.