国際先端科学技術研究機構（IROAST）は、ペンシルバニア州立大学所属、Derek Elsworth教授（IROAST客員教授）による、第140回IROASTセミナーを下記のとおり開催いたします。興味のある方はどなたでもご参加いただけます。

多くの皆さまのご参加をお待ちしております。

※本セミナーは英語にて行います。事前登録は不要です。

1. 日　時：令和7年1月8日（水）14:40～16:10
2. 会　場：黒髪南 C8, 2F, Room 221 (工学部2号館)〈58番〉

3. 講演者・タイトル（Speaker & Title）：
   Prof. Derek Elsworth, Energy and Mineral Engineering & Geosciences, G3 Center and EMS Energy Institute, Pennsylvania State University, University Park, USA
   “Seismicity-Permeability Linkages in Fractured Reservoirs”

      4. 概要（Abstract）：Triggered seismicity is a key hazard where fluids are injected or withdrawn from the subsurface and may also impact permeability. We constrain maximum event magnitudes in triggered earthquakes by relating pre-existing critical stresses to fluid injection volume – to explain why some recorded events are significantly larger than anticipated seismic moment thresholds. This formalism is shown consistent with a number of uncharacteristically large fluid-injection-triggered earthquakes. Such methods of reactivation of fractures and faults through hydraulic stimulation in shear or in tensile fracturing are used routinely as a method to create permeability in the subsurface. Microearthquakes (MEQs) generated in such stimulations may be used as diagnostic of permeability evolution. Although high fidelity datasets are meager, the EGS-Collab and Utah FORGE demonstration projects both provide high fidelity data sets that concurrently track permeability evolution and triggered seismicity. Machine learning deciphers the principal features of MEQs and the resulting permeability evolution that best track changes in permeability – with transfer learning methods allowing robust predictions across multiple geological settings. Changes in permeability on reactivated fractures in both Mode I and II suggest that permeability () scales with the seismic moment () of individual MEQs as . This scaling relation is exact at early time but degrades with successive MEQs but presents a method for characterizing crustal permeability evolution using MEQs.

Biosketch

Derek Elsworth is G. Albert Shoemaker Chair, Professor of Energy and Mineral Engineering and Geosciences and co-director of the Center for Geomechanics, Geofluids, and Geohazards at Penn State. His interests are in the areas of computational mechanics, rock mechanics, and in the mechanical and transport characteristics of fractured rocks, with application to geothermal energy, the deep geological sequestration of radioactive wastes and of CO₂, unconventional hydrocarbons including coal-gas, tight-gas-shales and hydrates, and instability and eruption dynamics of volcanoes.

http://www.ems.psu.edu/~elsworth/

       5. 世話人： 才ノ木　敦士　准教授　（大学院先端科学研究部）
                             Email：atsushi_sainoki@kumamoto-u.ac.jp

【IROASTセミナーに関するお問合せ】
平川
Email:szk-kiko@jimu.kumamoto-u.ac.jp

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IROAST will have the 140th IROAST Seminar by IROAST Visiting Professor Derek Elsworth, Pennsylvania State University, University Park, USA as follows.
Anyone interested in this seminar is more than welcome. Pre-registration is not required.
We hope to see you at the seminar.

1. Date and time: January 8th (Wednesday), 2:40 pm ~ 4:10 pm
2. Venue:  Room 221 (2F), Kurokami South C8  (Faculty of Engineering Bldg. 2)
3. Speaker, Title & Abstract: Referred to above.
4. Organizer: Assoc. Prof. Atsushi SAINOKI (FAST, Kumamoto University)
   E-mail: atsushi_sainoki@kumamoto-u.ac.jp
5. Remarks: This seminar will be held in English.

IROAST Seminar inquiries
Hirakawa (Ms.)
szk-kiko@jimu.kumamoto-u.ac.jp