Among the number of active volcanes of Jawa this is the lowest and smallest in dimension. Seen from the western shore of the lake (ranu) Lamongan or Glagah, his right summit, which his a cone-shaped form is visible under a view angle of 9'54', and his sharp angular left summit under an angle of 7' 22' above the horizon.
After the volcanic destruction in 1931 the W foot of the mountain was harassed by heavy banjirs, which beat in pieces the bridges and covered fields with sand. The banjir problem of the Merapi was studied in detail by K.G.R. Schmidt, a separate detailed report about this is in preparation by him.
The ladumasses were deeper cut in the course of the mouths and it appears always clearer, that they were built of a heterogen, lightbrown colored sand mass, where in-between irregularly scattered, the stones occurred as individuals or as bouldertrails.
Almost all authors are the opinion, that the well - known wedusgembel, which caused death and destruction on the western slope of the Merapi, originated from the hot lava avalanches (glowing avalanches), which rolled down along the slides, whereas 'shout-out' wedusgmbel have not taken place.
In the night of May 19th to the 20th, 1919 the nature powers again have shown their everything destructing violence. The contents of the craterlake of the G.Kelut was suddenly ejected over the craterwalls.
Sebagai tindak lanjut/kelanjutan dari pengukuran deformasi jarak horizontal Gunung Tangkubanparahu. Maka awal bulan Agustus 1986 dilakukan pengukuran ulang terhadap titik ukur deformasi baik yang mobile maupun yang permanent dengan menggunakan peralatan Range Master III dan distomat (DI 20).
Pemetaan ini dilakukan untuk membuat peta kawasan rawan bencana G.Lawu, dimana didalam peta ini tergambarkan daerah - daerah yang kemungkinan terkena bencana letusan gunung api berikut potensi bahaya dari G. Lawu jika meletus.
Kegiatan inventarisasi bahan galian di komplek G. Cireme, meliputi sekitar kabupaten Cirebon, Kuningan, dan Majalengka, Jawa Barat dibiyai oleh Proyek Penyelidikan dan Pengamatan Gunungapi yang telah dijadwalkan dalam tahun anggaran 1998/1999.
Endapan belerang di Kawah Plupuh - G. Welirang mempunyai kualitas yang baik dengan kadar belerang 27, 26% sehingga potensi endapan belerang di Kawah Plupuh - G. Welirang cukup ekonomis untuk ditambang.
Puncak G. Tangkubanparahu bagian timurlaut teramati telah mengalami penurunan, sehingga bagian punak G. Tangkubanparahu terbuka kearah tersebut. Pengamatan di lapangan, kawah - kawah G. Tangkubanparahu tersebar merupakan suatu kelurusan dengan arah barat-timur, dari Kw. Baru, Kw. Upas, Kw. Ratu, Kw. Domas, Kw. Badak, Kw. Siluman, dan Kw. Jarian.