The primary drilling objective at Site C0026 was to characterize the complete section of the Pacific plate sedimentary rocks and underlying uppermost basement, which are inputs to the subduction zone, using a combination of logging-while-drilling (LWD) measurements and coring. The composition, spatial distribution, and thickness of the sedimentary rocks that reside on the oceanic plate outboard of the trench at a subduction zone are thought to be key controls on the seismogenic behavior of the subduction megathrust, as well as on the long-term evolution of the subduction forearc (e.g., Underwood, 2007). For example, the composition and burial history of sedimentary rocks determines rock mechanical properties such as the frictional strength and cohesion of the rocks, hydrologic properties such as rock porosity and permeability, and the mineral-bound water content, which determines the fluid budget for dehydration reactions during diagenesis and metamorphism. These parameters dictate the overall strength of the sedimentary rocks, so they influence the propagation of the megathrust through the input section. After the input section is subducted, they also dictate the frictional stability of the fault and how it changes with depth. Identifying the input sedimentary rocks and measuring their thicknesses is therefore an important step in understanding the factors that control the magnitude of shallow earthquake slip on subduction zones.
", "doi": "10.14379/iodp.proc.405.104.2025", "issn": "2377-3189", "publisher": "International Ocean Discovery Program", "publication": "Proceedings of the International Ocean Discovery Program", "publication_date": "2025-12-20", "volume": "405", "pages": "405_104" }, { "id": "authors:3bss3-zvh35", "collection": "authors", "collection_id": "3bss3-zvh35", "cite_using_url": "https://authors.library.caltech.edu/records/3bss3-zvh35", "type": "book_section", "title": "Expedition 405 methods", "author": [ { "family_name": "Kirkpatrick", "given_name": "J.", "orcid": "0000-0001-7504-6968" }, { "family_name": "Fulton", "given_name": "P." }, { "family_name": "Ujiie", "given_name": "K.", "orcid": "0000-0003-2252-8183" }, { "family_name": "Conin", "given_name": "M.", "orcid": "0000-0002-6072-3919" }, { "family_name": "Regalla", "given_name": "C.", "orcid": "0000-0003-2975-8336" }, { "family_name": "Kodaira", "given_name": "S.", "orcid": "0000-0002-5774-2561" }, { "family_name": "Okutsu", "given_name": "N.", "orcid": "0000-0003-0474-961X" }, { "family_name": "Maeda", "given_name": "L.", "orcid": "0000-0002-0668-279X" }, { "family_name": "Toczko", "given_name": "S.", "orcid": "0000-0002-0906-8592" }, { "family_name": "Eguchi", "given_name": "N.", "orcid": "0009-0004-7728-2875" }, { "family_name": "Bellanova", "given_name": "P.", "orcid": "0000-0001-5204-8602" }, { "family_name": "Brown", "given_name": "C.", "orcid": "0000-0002-3956-0406" }, { "family_name": "Brunet", "given_name": "M.", "orcid": "0000-0002-8896-4669" }, { "family_name": "Castillo", "given_name": "M.", "orcid": "0009-0006-1897-0007" }, { "family_name": "Chang", "given_name": "Y.-C.", "orcid": "0000-0003-4941-5437" }, { "family_name": "Doan", "given_name": "M.-L.", "orcid": "0000-0002-6437-9756" }, { "family_name": "Everard", "given_name": "J.", "orcid": "0000-0003-2344-0415" }, { "family_name": "Fintel", "given_name": "A.", "orcid": "0000-0002-8247-2380" }, { "family_name": "Ford", "given_name": "J.", "orcid": "0000-0003-4936-8909" }, { "family_name": "Fukuchi", "given_name": "R.", "orcid": "0000-0001-9953-2047" }, { "family_name": "Gough", "given_name": "A.", "orcid": "0000-0001-5146-3476" }, { "family_name": "Guo", "given_name": "H.", "orcid": "0000-0002-8516-4244", "clpid": "Guo-Huiyun" }, { "family_name": "G\u00fcrer", "given_name": "D.", "orcid": "0000-0001-5884-9160" }, { "family_name": "Hackney", "given_name": "R.", "orcid": "0000-0001-5306-2713" }, { "family_name": "Hagino", "given_name": "M.", "orcid": "0009-0005-5602-898X" }, { "family_name": "Hamada", "given_name": "Y.", "orcid": "0000-0001-7196-9271" }, { "family_name": "Hosono", "given_name": "H.", "orcid": "0009-0005-6079-4812" }, { "family_name": "Ijiri", "given_name": "A.", "orcid": "0000-0001-7140-1491" }, { "family_name": "Ikari", "given_name": "M.", "orcid": "0000-0002-8164-411X" }, { "family_name": "Ishikawa", "given_name": "T.", "orcid": "0000-0003-2886-7282" }, { "family_name": "Iwai", "given_name": "M.", "orcid": "0000-0001-7489-1262" }, { "family_name": "Jeppson", "given_name": "T.", "orcid": "0000-0001-5526-5530" }, { "family_name": "Jurado", "given_name": "M.-J.", "orcid": "0000-0001-8165-2729" }, { "family_name": "Kamiya", "given_name": "N.", "orcid": "0000-0001-7460-3806" }, { "family_name": "Kanamatsu", "given_name": "T.", "orcid": "0000-0002-7108-4534" }, { "family_name": "LaPlante", "given_name": "A.", "orcid": "0000-0003-4770-2619" }, { "family_name": "Lin", "given_name": "W.", "orcid": "0000-0003-3228-2789" }, { "family_name": "Miyakawa", "given_name": "A.", "orcid": "0000-0001-8089-6406" }, { "family_name": "Morono", "given_name": "Y.", "orcid": "0000-0001-8928-4254" }, { "family_name": "Nakamura", "given_name": "Y.", "orcid": "0000-0001-6750-2791" }, { "family_name": "Nicholson", "given_name": "U.", "orcid": "0000-0003-0746-8549" }, { "family_name": "Okuda", "given_name": "H.", "orcid": "0000-0002-5276-0058" }, { "family_name": "Pei", "given_name": "P.", "orcid": "0009-0004-4089-4149" }, { "family_name": "Pizer", "given_name": "C.", "orcid": "0000-0001-9410-529X" }, { "family_name": "Rasbury", "given_name": "T.", "orcid": "0000-0003-0591-4461" }, { "family_name": "Robertson", "given_name": "R.V.M.", "orcid": "0000-0002-0927-3377" }, { "family_name": "Ross", "given_name": "C.", "orcid": "0000-0001-5669-7327" }, { "family_name": "Satolli", "given_name": "S.", "orcid": "0000-0001-9848-9745" }, { "family_name": "Savage", "given_name": "H.", "orcid": "0000-0002-5773-7279" }, { "family_name": "Schaible", "given_name": "K.", "orcid": "0009-0009-5438-2781" }, { "family_name": "Shreedharan", "given_name": "S.", "orcid": "0000-0002-5825-8739" }, { "family_name": "Sone", "given_name": "H.", "orcid": "0000-0001-5525-1294" }, { "family_name": "Sun", "given_name": "C.", "orcid": "0000-0002-3668-346X" }, { "family_name": "Turel", "given_name": "C." }, { "family_name": "Uchida", "given_name": "T.", "orcid": "0000-0001-9927-7103" }, { "family_name": "Yamaguchi", "given_name": "A.", "orcid": "0000-0003-0974-6530" }, { "family_name": "Yamamoto", "given_name": "Y.", "orcid": "0000-0003-2514-3174" }, { "family_name": "Yoshimoto", "given_name": "T.", "orcid": "0000-0003-4676-3823" }, { "family_name": "Zhang", "given_name": "J.", "orcid": "0000-0002-2546-8633" }, { "family_name": "Wspanialy", "given_name": "A." }, { "family_name": "Le Ber", "given_name": "E.", "orcid": "0000-0002-8020-2029" }, { "family_name": "Rydzy", "given_name": "M.B.", "orcid": "0009-0005-6467-9520" }, { "family_name": "Schuba", "given_name": "N." } ], "abstract": "This chapter documents the methods used for shipboard measurements and analyses during International Ocean Discovery Program (IODP) Expedition 405, Tracking Tsunamigenic Slip Across the Japan Trench (JTRACK). We conducted riserless operations at Sites C0019 and C0026 (Table T1). Two temperature sensor observatories were installed at Site C0019. Logging while drilling and coring were performed at Sites C0019 and C0026. Methods for postexpedition research conducted on Expedition 405 samples and data will be described in individual scientific contributions published after the expedition.
\nAll shipboard scientists contributed to the completion of this volume. Because of the long length of Expedition 405 (106 days, 6 September–20 December 2024), staffing was staggered. The shipboard science party was divided into two science party staffing windows. Window 1 included 26 scientists (6 September–30 October), and Window 2 included 25 scientists (25 October–21 December). The Window 1 to Window 2 handover occurred during a 6 day crossover period with staggered onboarding and offboarding. Six Co-Chief Scientists served in overlapping shifts of two or three at a time, and at least one Expedition Project Manager was on board at all times.
", "doi": "10.14379/iodp.proc.405.102.2025", "issn": "2377-3189", "publisher": "International Ocean Discovery Program", "publication": "Proceedings of the International Ocean Discovery Program", "publication_date": "2025-12-20", "volume": "405" }, { "id": "authors:bdc4d-6p090", "collection": "authors", "collection_id": "bdc4d-6p090", "cite_using_url": "https://authors.library.caltech.edu/records/bdc4d-6p090", "type": "article", "title": "Triggering Intensity Changes Over Time and Space as Measured by Continuous Waveforms in Southern California", "author": [ { "family_name": "Guo", "given_name": "Huiyun", "orcid": "0000-0002-8516-4244", "clpid": "Guo-Huiyun" }, { "family_name": "Brodsky", "given_name": "Emily E.", "orcid": "0000-0002-6855-6860" }, { "family_name": "Miyazawa", "given_name": "Masatoshi", "orcid": "0000-0002-3319-1216" } ], "abstract": "Dynamic triggering of earthquakes is when seismic waves from earthquakes induce seismic activity at a distance. The observability of the seismic wave stresses and their results presents a unique opportunity to understand earthquake interactions and associated hazard implications. The extent and timing of dynamic triggering at given specific stress changes still remain inadequately predicted due to limited studies and data sets. In particular, the requirement for complete, well\u2010characterized catalogs to detect triggering systematically seriously limits the types of studies possible. To address this, we utilized 7\u2010year continuous waveform data from 239 stations in southern California and used PhaseNet for phase picking to identify local earthquakes and measure triggering without constructing any earthquake catalog. We map the triggering intensity over the region and find that overall, the Mojave segment of the San Andreas is the most easily triggered region. However, the spatial pattern changes after the Ridgecrest earthquake and the area appears to become much less prone to triggering, likely due to an exhaustion of the faults near failure in the immediate aftermath of the Ridgecrest sequence. We further observe a slow decay rate of dynamic triggering and conclude that low\u2010frequency waves (0.04–0.1 Hz) may be more effective in dynamic triggering than high\u2010frequency waves (1–3 Hz) which is consistent with a rate\u2010state assisted aseismic creep or hydrological triggering mechanism.
", "doi": "10.1029/2024jb030004", "issn": "2169-9313", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research: Solid Earth", "publication_date": "2025-06", "series_number": "6", "volume": "130", "issue": "6", "pages": "e2024JB030004" } ]