Prof. Dr. Niyazi Türkelli worked as an Assistant Professor at the Seismological-Geophysical Observatory of King Saud University in Saudi Arabia-Riyadh, responsible for the planning, installation, and operation of the Saudi Arabian National Seismic Network between years 1985- 1991. During the years between 1994 and 1997, he participated in the Disarmament Conference for the Ad Hoc Scientific Experts Group at the United Nations in Geneva as a national delegate. As the Head of the Seismology Laboratory at KOERI between 1992-1999, Prof. Türkelli played a very important role in the establishment of online Broadband Seismic Networks in Turkey and served as the Deputy Director of KOERI between 2004-2006. Between 2003 and 2006, he served as the founding director of the Belbaşı Nuclear Tests Monitoring Center. He was also a member of the "IRIS-International Development Seismology Committee" between 2010-2013. He retired from KOERI Geophysics Department in 2015. Prof. Dr. Niyazi Türkelli passed away on April 19, 2021.