SEG (Society of Exploration Geophysicists)

SEG (Society of Exploration Geophysicists)

The organization that promotes the science of applied geophysics and the education of geophysicists. Located in Tulsa, Oklahoma, USA. SEG founded in 1930, SEG purpose is fosters the expert and ethical practice of geophysics in the exploration and development of natural resources, in characterizing the near surface, and in mitigating earth hazards. SEG have 35 000 members in 138 countries, fulfills its mission through its publications, conferences, forums, Web sites, and educational opportunities

In 1930, twenty-nine men and one woman met in Houston at the University Club to found the Society of Economic Geophysicists. SEG have a first president named Donald C. Barton. In 1932, SEG became "Division of Geophysics” of the AAPG. Until 2008 SEG opened the first office outside the US in Beijing, China.

SEG is dedicated to advancing and promoting the science of geophysics, especially as it relates to exploration and development of petroleum and other minerals, as well as environmental concerns. Membership is open to geoscience disciplines. SEG have 4 type of membership. First Active Membership, must be actively engaged in practicing or teaching geophysics or a related scientific field. Second, Associate membership, must be actively interested in geophysics. Third, Student membership, must be a graduate or undergraduate student in good standing in residence at a recognized university or college. Fourth, Junior membership, open to all pre-university students. And the last is Corporate membership, a corporation or organization that must be actively engaged in geophysical exploration, geophysical research, or a related field, or in furnishing services or products used in geophysical exploration or research, and must have an active interest in supporting the objectives of the society.

SEG help all geoscientist to publish the jurnal of geosience. SEG publishes two journals. Geophysics, published by SEG since 1936, is an archival journal encompassing all aspects of research, exploration, and education in applied geophysics. The Leading Edge (TLE) is a gateway publication introducing new geophysical theory, instrumentation, and established practices to scientists in a wide range of geoscience disciplines. Most material is presented in a semitechnical manner that minimizes mathematical theory and emphasizes practical applications.

IPA (Indonesian Petroleum Association)

IPA(Indonesian Petroleum Association)

Following the introduction of the production-sharing concept in 1966, Indonesia experienced a period of accelerated growth in petroleum activities, especially in offshore exploration. As the number of individuals and organizations participating in these activities increased it became clear that the establishment of an industry association would be beneficial to further development to the Nations resources as well as the petroleum community. Rather than forming separate associations or branches of other petroleum orientated international associations and societies, it was felt that the industry could be better served by one organization through which direct and free communication of all professional industry skills and disciplines could be realised. With this objective in mind, representatives from seven organizations - Pertamina, Lemigas, BP, Caltex, Jenny Joint Venture, Shell and Union Oil, form a steering committee in 1969 for the purpose of establishing an association of individuals and companies connected with the Indonesian petroleum industry. The result was the charter of the Indonesian Petroleum Association, formally announced on March 24, 1971.
During the last 30 years the IPA has already achieved much in terms of bringing people with common interests together and contributing to Indonesia's national development. In the process it has assisted in the realisation of company member goals, the advancement of individual members professional interest and has acted as successful bridge between industry and the Government of Indonesia. The IPA is the chosen vehicle to promote partnership in the Indonesian petroleum industry.

Nearly same with other organization geology in the world The aims and objectives of the Association are to utilize non-confidential and non-proprietary information to promote the exploration, producing, refining/manufacturing, distribution and marketing aspects of the petroleum and geothermal industries in Indonesia, through:
• Studying problems relating to such aspects of the petroleum industry at the national level and possible solutions of these problems.
• Studying modern methods of the petroleum industry, which have been adopted in other countries for application in Indonesia.
• Fostering a mutual respect between the Members of the Association, both private and Government (it being understood that no decision or action of the Association shall affect any contracts to which any of the members are parties).
• Advancing new ideas relative to such aspects of the petroleum industry.
• Fostering a spirit of scientific research among the Members of the Association.
• Establishing contact and cooperation with similar professional organizations outside Indonesia.
• Disseminating objective information and analysis concerning such aspects of the petroleum industry.
• Maintenance of a high standard of professional conduct on the part of the Association Members.
• Promotion of the development of the infrastructure necessary to support the petroleum industry in Indonesia.
• Familiarization of the general public and educational institutions with current developments and problems of the petroleum industry.
• Giving assistance to and encouraging potential university graduated in preparing for a career in the petroleum industry

Panas Bumi

Suatu model lapisan bumi berikut unsur-unsur yang dominan dimasing-masing lapisan tersebut telah dirilis oleh J. Marvin Herndon dalam CURRENT SCIENCE, VOL. 88, NO. 7, 10 APRIL 2005. Model tersebut, sebagaimana yang ditampilkan di atas, merupakan model terakhir yang diakui oleh kalangan ilmuwan geofisika, meskipun masih diperdebatkan khususnya pada bagian inti bumi (inner core) apakah keadaannya berupa liquid (cairan) atau solid (padat) atau plasma? Adapun pada lapisan outer-core, para ilmuwan sepakat bahwa kandungan unsur pada lapisan tersebut didominasi oleh Fe (iron atau unsur besi).

Sementara itu, beberapa pakar dari University College London telah melakukan simulasi dengan superkomputer Cray T3E untuk mengukur temperatur tinggi yang bisa melelehkan besi dalam tekanan yang sangat tinggi sebagaimana yang ada di inti bumi. Hasil simulasi tersebut menunjukkan bahwa titik leleh atau titik lebur besi adalah pada suhu 6700 Kelvin pada tekanan diantara inner-core dan outer-core di perut bumi. Temuan ini mendukung model sebelumnya yang mengatakan bahwa temperatur inti bumi berkisar pada suhu tersebut.

Dari sini sebuah pertanyaan sainstifik bisa dimunculkan, yaitu darimana inti bumi mendapatkan energi panas yang dahsyat tersebut? Para ilmuwan masih percaya bahwa semua itu dihasilkan oleh reaksi fisi nuklir alamiah (geo-reaktor) yang terjadi di dalam inner-core. Itulah sebabnya dalam model (gambar) di atas, Herndon menempatkan uranium sebagai unsur yang mendominasi bagian inner-core, dimana kita semua tahu bahwa uranium adalah salah satu unsur radioaktif yang bisa menghasilkan reaksi fisi nuklir. Asumsi akan adanya georeaktor tersebut cukup tepat untuk menjawab teka-teki mengenai keberadaan isotop helium yang begitu melimpah, sekaligus juga menjelaskan fenomena variasi medan geomagnetik bumi. Demikianlah logikanya.
Mungkin ada baiknya menyaksikan film fiksi-ilmiah berjudul The Core yang bercerita tentang ekspedisi para ilmuwan menuju inti bumi. Mereka turun ke dasar bumi dari palung Mariana di samudra Pasifik yang merupakan palung terdalam di dunia dengan kedalaman mencapai 11 km. Tapi saran saya jangan buru-buru percaya sama kondisi perut bumi yang ditampilkan dalam film tersebut. Namanya juga fiksi.

Inspired By DR. Supriyanto
Fisika Universitas Indonesia

Plate Tectonic Processes

Kerak bumi (crust) terdiri dari dua jenis lempengan (plate) yaitu lempeng samudera (oceanic plate) dan lempeng benua (continental plate). Lempeng benua lebih tebal dibandingkan lempeng samudera. Namun densitas lempeng samudera lebih besar dari pada lempeng benua. Kedua jenis lempeng tersebut berada dalam posisi mengapung di atas mantel bumi yang berupa semi-cairan yang sangat panas yang dikenal dengan magma. Cairan panas tersebut tidak diam, melainkan berputar atau mengalir mengikuti pola konveksi akibat perbedaan temperatur yang tinggi antara inti bumi dan mantel bumi. Aliran konveksi tersebut mempengaruhi kestabilan lempeng benua dan lempeng samudera sehingga lempeng-lempeng tersebut bergerak bahkan saling bertabrakan satu sama lain. Pada saat lempeng samudera bertabrakan dengan lempeng benua, karena memiliki desitas lebih tinggi, maka lempeng samudera melesak atau menunjam (subducting) ke bawah lempeng benua. Inilah yang terjadi di bagian selatan pulau Jawa dan bagian barat pulau Sumatera. Lempengan Indo-Australia yang memuat Australia, India dan Samudera Hindia melesak ke bawah lempeng Eurasia yang memuat benua Asia, termasuk Indonesia. Pada saat menghunjam ke bagian yang lebih dalam dimana temperatur dan tekanannya lebih tinggi, lempeng samudera tersebut meleleh menjadi magma. Adanya rekahan-rekahan di bagian lempeng benua sebagai akibat dari gesekan dan tabrakan tadi membuka jalan bagi magma untuk menerobos ke atas mendekati permukaan bumi sekaligus mendorong lempeng benua membentuk gunung api. Proses ini disebut intrusi magma. Sebenarnya, deretan gunung api semacam inilah yang membentuk Sumatera, Jawa, Bali, Lombok dan pulau-pulau dengan gunung api lain sampai ke Laut Banda. Terkadang magma tersebut memperoleh jalan untuk menuju ke permukaan bumi dan muncul sebagai lava. Ini terjadi pada saat terjadi letusan gunung api.