Danny, tks infonya. Salam,
Yatno From: Danny Hilman Natawidjaja [mailto:danny.hil...@gmail.com] Sent: Monday, July 16, 2012 2:14 PM To: iagi-net@iagi.or.id Subject: RE: [iagi-net-l] Erupsi besar gunungapi, abad ke 13 di Indonesia ? Dating carbon tentu bisa untuk ratusan tahun pak, kecuali yang umurnya dibawah 250 tahunan BP (1950) alias setelah 1700 Masehi uncertainty sangat besar. Saya lihat pada chart (di-attach) untuk koreksi umur C-14 yang 700-an tahun BP ke kalendar masehinya (=1250M) okay pak. Lab yang punya reputasi internasional bagus di Beta Analytic di http://www.radiocarbon.com/. Salam DHN From: Yustinus Suyatno Yuwono [mailto:yuw...@gc.itb.ac.id] Sent: 16 Juli 2012 13:47 To: iagi-net@iagi.or.id Subject: RE: [iagi-net-l] Erupsi besar gunungapi, abad ke 13 di Indonesia ? OK, Kalau sifatnya masih spekulatif gini ya sudah kita tunggu aja published paper- nya. Wah saya mungkin ketinggalan zaman ya, apa ada instrument baru yg bis dating charcoal sampai skala ratusan tahun? Mungkin Danny tahu lab mana ya? Salam, YSY From: Danny Hilman Natawidjaja [mailto:danny.hil...@gmail.com] Sent: Saturday, July 07, 2012 7:27 AM To: iagi-net@iagi.or.id Subject: RE: [iagi-net-l] Erupsi besar gunungapi, abad ke 13 di Indonesia ? Pak Yatno, Frank Lavigne memang belum mau bilang Gunung Api di Indonesia yang mana yang meletus tahun 1257/8 AD yang menyebabkan dunia menjadi dingin dan memasuki jaman es kecil itu (i.e. little ice age). Mungkin takut dibajak orang lain meneliti/mempublikasikannya. Tapi sebagian ahli menduga kuat yang dimaksud adalah Rinjani. Di http://en.wikipedia.org/wiki/Mount_Rinjani disebutkan kaldera Rinjani terbentuk di Abad 13, tapi belum ada info tahun persisnya. Di copy-an berita di bawah katanya sudah ada charcoal dating yang menunjuk ke 1210-1260 AD untuk letusan Rinjani itu. Jadi bagi saya sih logis saja kalo mengajukan Rinjani sebagai tersangka-nya kalau memang info umur kaldera ini benar. Hayoo siapa yang mau ngedulu-in si Frank, buruan J Salam, DHN Di bawah ini komentar seorang ahli tentang isue Si Frank dan Rinjani itu: http://goodnewsfromindonesia.org/category/nature/ If youve been following the news out the AGU Chapman Meeting of Volcanoes & the Atmospheremeeting going on this week, you might have seen some interesting news about the missing 1258 A.D. eruption. I wrote about the eruption a few months back, speculating on some potential volcanoes that could be the culprit for this climate-altering event. However, trying to match a sulfate signal on the poles with a volcano somewhere on the planet is hard, so finding that smoking gun is a challenge to say the least. However, Franck Lavigne from the Panthéon-Sorbonne Universitys Laboratory of Physical Geography in Meudon, France claimed to have solved the mystery. It isnt that simple, though. Lavigne will not reveal the site of the eruption until his study is published (it may or may not be submitted for peer review at this point). So, instead of sharing news of his discovery, he showed the data he used to solve the mystery but never revealed what volcano it was! What harm could come from Lavigne revealing his location before the article is published, especially if he is willing to show data that supposedly correlates the sulfate and ash composition in the polar record with the terrestrial record of the mystery volcano? Overall, this is shocking behavior for a geologist at a large meeting such as this people commonly discuss data and information that has not be published yet, so why Lavigne chose to do this is beyond me (unless you want to think theatrics are part of the rationale). The consensus of people at the meeting (N.B., I am not at the meeting) is that the mystery volcano is in Indonesia. Lavigne wouldnt confirm or deny this assessment, but it got me thinking what might a contender be for a caldera eruption in Indonesia during the 13th century. Indonesia is filled with volcanoes, and as I mentioned a few weeks back when I discussed a recent study by Salisbury and others (2012), we really dont have a lot of good ages for Indonesian eruptions prior to ~1800 A.D. However, one very likely candidate might be the ~6 x 8.5 km Rinjani caldera. Rinjani hosts a caldera that may have formed in the 13th century, so it not only fulfills the role of being a large eruption but also falls within the right century. We dont have any good ages for the caldera eruption beyond some charcoal dated at 1210-1260 A.D. However, with the evidence that Lavingnes volcano is in Indonesia and how little we know about the caldera eruption at Rinjani, it makes sense that Rinjani could be an excellent candidate for an eruption that could be matched with the polar sulfate and ash. At this point, all we can do is wait for Lavignes study to be published, but we might be able to narrow the search for the 1257-58 eruption to Indonesia and even to a target caldera that might be the weapon of choice. From: Yustinus Suyatno Yuwono [mailto:yuw...@gc.itb.ac.id] Sent: 06 Juli 2012 15:23 To: iagi-net@iagi.or.id Subject: RE: [iagi-net-l] Erupsi besar gunungapi, abad ke 13 di Indonesia ? Rekan Danny, Gak peduli Bule atau Melayu, kalo statement nya (maaf) terlalu berani dan menurut saya (terbatas pada disiplin ilmu yang saya tekuni) kurang logis ya saya akan berikan opini. Contohnya ini: G. Rinjani meletus dengan skala letusan 7 pada abat 13???????? Begitu bodohnya orang Indonesia pada waktu itukah, sehingga sama sekali tidak ada catatan mengenai peristiwa alam begitu dahsyatnya? Misal dalam Babat Tanah Jawi atau legenda rakyat dan sejenisnya (barangkali Awang Satyana bisa memberi pencerahan krn koleksi bukunya luar biasa, sebagai referensi). Kedua, tidak ada catatan dari Direktorat Volkanologi yang pernah saya baca dan dengar mengenai super erupsi Rinjani pada abat tersebut? Ketiga, data yang kita lihat lewat satelit dapat memperlihatkan berapa ukuran kaldera dari G Rinjani ini yang diakibatkan super erupsi ini? Kalau melihat ukuran kalderanya mungkin Kaldera Tengger lebih prospek jadi kandidatnya (hanya melihat ukuran kaldera), tapi saya tidak tahu apakah Dir Volk kita sudah punya data umur kapan terbentuknya kaldera Tengger (dan juga Rinjani?). Danny, jangan tersinggung kalau saya ber-opini keras terutama yang menyangkut bidang saya, inilah gunanya sharing pengetahuan. Salam, Yatno (YSY). From: Danny Hilman Natawidjaja [mailto:danny.hil...@gmail.com] Sent: Tuesday, July 03, 2012 1:40 PM To: iagi-net@iagi.or.id Subject: RE: [iagi-net-l] Erupsi besar gunungapi, abad ke 13 di Indonesia ? Salah besar pak. Culpritnya memang Rinjani. Bisa dilihat di: http://www.sciencenews.org/view/generic/id/341497/title/13th_century_volcano _mystery_may_be_solved http://en.wikipedia.org/wiki/Mount_Rinjani http://volcano.oregonstate.edu/aggregator/sources/9 From: Yustinus Suyatno Yuwono [mailto:yuw...@gc.itb.ac.id] Sent: 03 Juli 2012 12:05 To: iagi-net@iagi.or.id Subject: RE: [iagi-net-l] Erupsi besar gunungapi, abad ke 13 di Indonesia ? He geodukun lagi????? YSY From: abacht...@cbn.net.id [mailto:abacht...@cbn.net.id] Sent: Saturday, June 16, 2012 7:48 PM To: iagi-net@iagi.or.id Subject: Re: [iagi-net-l] Erupsi besar gunungapi, abad ke 13 di Indonesia ? Gunung Rinjani, Vick. Powered by Telkomsel BlackBerry® _____ From: Rovicky Dwi Putrohari <rovi...@gmail.com> Date: Sat, 16 Jun 2012 19:31:05 +0700 To: IAGI<iagi-net@iagi.or.id>; geologi...@googlegroups.com <mailto:geologi...@googlegroups.com%3cgeologi...@googlegroups.com> <geologi...@googlegroups.com> ReplyTo: <iagi-net@iagi.or.id> Subject: [iagi-net-l] Erupsi besar gunungapi, abad ke 13 di Indonesia ? Gunung mana ya ? Rdp http://www.sciencenews.org/view/generic/id/341497/title/13th_century_volcano _mystery_may_be_solved 13th Century Volcano Mystery May Be Solved - Science News SELFOSS, Iceland One of the biggest mysteries in volcanology may finally have a solution. An eruption long thought to have gone off in the year 1258, spreading cooling sulfur particles around the globe, happened the year before in Indonesia, scientists report. Until now, researchers have known a big volcano went off somewhere in the world around that time, but they didnt know exactly where or when. The new report still remains something of a mystery. Franck Lavigne, a geoscientist at Panthéon-Sorbonne University's Laboratory of Physical Geography in Meudon, France, showed data and close-up photographs of the remains of the perpetrator volcano on June 14 at an American Geophysical Union conference on volcanism and the atmosphere. But he declined to name the specific volcano, saying he had agreed with his international colleagues not to identify it until the work is published in a peer-reviewed journal. We have new and solid evidence for the biggest volcanic eruption in 7,000 years, Lavigne said. Consensus in the meeting hallways was that he showed pictures of Indonesia. Lavigne would say only that Indonesia has more than 130 active volcanoes. Scientists know a big eruption must have happened in the mid-13th century because ice cores from Greenland and Antarctica dating to that time contain huge amounts of sulfur. Tree rings, historical records and other evidence also show that the planet cooled soon thereafter. Big volcanic eruptions can spew sulfur particles into the upper atmosphere, where they spread around the globe and reflect sunlight, temporarily chilling the planet. Leading candidates for the 1258 eruption have included Mexicos El Chichón, which also erupted in 1982, and Quilotoa in the Ecuadorean Andes. But the chemical composition of rocks from those volcanoes, among other factors, dont really match the 1258 sulfur from ice cores. At the meeting, Lavigne showed geochemical analyses of rocks from his mystery volcano. They matched the chemistry of the polar sulfur almost perfectly. The rocks come from a caldera, the collapsed remains left behind after a large volcanic eruption drains an underground magma chamber. Newly unearthed historical records and other evidence show that climate changes were already happening in the region by the winter of 1257-1258, Lavigne said. We think the eruption may have been in the late spring or summer of 1257, he said. Thats nearly a year earlier than previously thought. Computer simulations suggest the eruption sent pumice flying into the air more than 40 kilometers high, showering debris for tens of kilometers around. The eruption would have ranked a 7 on the volcanic explosivity scale that measures an eruptions magnitude. That scale tops out at 8. Still, volcanologists have spent decades looking for the source of the 1257/1258 eruption. Its not yet clear whether Lavigne will be able to marshal enough evidence to convince everyone else. -- "Sejarah itu tidak pernah usang untuk terus dipelajari"
