By the paroxismal phenomena on December 18 and 19, 1930 in the W wall of the mountain summit a breach originated with a length of 1350 π. This reached an elevation of 2150 a downwards and near the summit it was about 200 m in width. A big part of the old domes on the summit, including the lavastream of 1922 has disappeared.
The summit of G. Merapi is formed by a lava-plug; a cratershaped decline, such as the most volcanoes possess, is not present. However it is known,-thanks to the many interest, with which the G. Herapi in the pant century obtained, that the volcano in another stage of eruptive activity certainly owed such a cratershaped decline.
On October 12, 1920 the inhabitants of the most high laying kampungs in the vicinity of the Blongkengravine were surprised by hot dustclouds and were killed by the burns. It appeared inmediately, that there was no outburst at all, as the summit slopes of the Merapi were, as far as they were overgrown in August and September, were still green as before (the reports from news papers concerning th…
The spreading of the Herapi products is of a great agrogeologic Importance, as the Merapi products compared with the rocks of other Java volcanoes are extraordinary fosforrich. Only towards one side these products could develop feely, namely in the plane of Solo, whare they border to that of the Lavu. To the S the spreading was stopped by the southern mountains, only in the area of the kali Opa…
As already earlier mentioned the G. Herapi exists of two morphologic clearly to be distinguished parts, an older eastern and a younger western part. From the sunnit of the old ringdike, only a small part remains (see portrait 14), of which the eastern part is named G. Pusunglondon (2694.3 a.s.) and the northern G. Paseban (2679= a.s.). The old volcano mantle of the G. Merapi has grown much more…
Dengan surat perintah No. 401/P/84 tanggal 4 Mei 1984 penulis ditugaskan untuk melakukan pekerjaan antara lain ialah :Mencari data kegiatan G. Merapi secara visual yang terjadi dewasa ini, data tersebut sebagai bahan perbandingan dengan bulan sebelumnya. Melakukan pemeriksaan laharan di S.Putih, S. Bebeng, S.Krasak dan tujuannya adalah untuk menduga volum endapan lahar dan penentuan daerah yang…
Pengamatan visual sering kali terhalang cuaca yang buruk, kabut mendung, gerimis - gerimis hujan yang menutup tubuh G. Merapi. Selama waktu cerah yang sejenak, asap, solfatar woro, Gendol, dan ladang yang lain berhembus dengan tekanan lemah setinggi maksimum 400 m. Dari Pos Pengamatan Babadan, Plawangan, dan Ngepos termati kubah lava yang meninggi dan bertambah besar.
Penyelidikan geomagnet G.Merapi dengan sistem telemetri radio telah dimulai sejak tahun 1978. Namun sampai saat ini masih sering juga timbul persoalan, misalnya kerusakan sensor akibat petir, kerusakan regulator pada sistem catu daya, dan sebagainya.
Sesuai dengan nota dinas Asisten Ekbang/Kesra untuk Sekretaris Wilayah/Daerah Tk. I Propinsi Sumatera Barat No. 4/BKLH/1988 tanggal 7 Januari 1988, perihal Pemberangkatan Tim Geologi penelitian Bahaya Letusan Gunung Merapi dan Bahaya Gelodo Gunung Talang, sebagai realisasi dana bantuan Gubernur Kepala Daerah Tk. I Propinsi Sumatera Barat kepada Kanwil Departemen Pertambangan dan Energi Sumatera…
Dalam laporan lapangan ini penulis menitikberatkan tentang aliran lahar hujan, terutama mengenai keselamatan kampung-kampung yang terletak disekitar jalur-jalur sungai yang kemungkinan akan dilaluinya. Hal ini berhubungan dengan gejala-gejala kenaikan kegiatan G. Merapi pada bulan Mei 1975. Survey dilakukan oleh 2 petugas dan dilaksanakan selama 14 hari