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Joseph Wartman

Publications and source records attributed to Joseph Wartman.

7 recordsLinked to original sources
USGS2023

Evidence of Seattle Fault earthquakes from patterns of deep-seated landslides

Earthquake‐induced landslides can record information about the seismic shaking that generated them. In this study, we present new mapping, Light Detection and Ranging‐derived roughness dating, and analysis of over 1000 deep‐seated landslides from the Puget Lowlands of Washington, U.S.A., to probe the landscape for past Seattle fault earthquake information. With this new landslide inventory, we observe spatial and temporal evidence of landsliding related to the last major earthquake on the Seattle fault ∼1100 yr before present. We find spatial clusters of landslides that correlate with ground motions from recent 3D kinematic models of Seattle fault earthquakes. We also find temporal patterns in the landslide inventory that suggest earthquake‐driven increases in landsliding. We compare the spatial and temporal landslide data with scenario‐based ground motion models and find stronger evidence of the last major Seattle fault earthquake from this combined analysis than from spatial or temporal patterns alone. We also compare the landslide inventory with ground motions from different Seattle fault earthquake scenarios to determine the ground motion distributions that are most consistent with the landslide record. We find that earthquake scenarios that best match the clustering of ∼1100‐year‐old landslides produce the strongest shaking within a band that stretches from west to east across central Seattle as well as along the bluffs bordering the broader Puget Sound. Finally, we identify other landslide clusters (at 4.6–4.2 ka, 4.0–3.8 ka, 2.8–2.6 ka, and 2.2–2.0 ka) in the inventory which let us infer potential ground motions that may correspond to older Seattle fault earthquakes. Our method, which combines hindcasting of the surface response to the last major Seattle fault earthquake, using a roughness‐aged landslide inventory with forecasts of modeled ground shaking from 3D seismic scenarios, showcases a powerful new approach to gleaning paleoseismic information from landscapes.

Bulletin of the Seismological Society of America↗
USGS2020

Rainfall triggers more deep-seated landslides than Cascadia earthquakes in the Oregon Coast Range, USA

The coastal Pacific Northwest USA hosts thousands of deep-seated landslides. Historic landslides have primarily been triggered by rainfall, but the region is also prone to large earthquakes on the 1100-km-long Cascadia Subduction Zone megathrust. Little is known about the number of landslides triggered by these earthquakes because the last magnitude 9 rupture occurred in 1700 CE. Here, we map 9938 deep-seated bedrock landslides in the Oregon Coast Range and use surface roughness dating to estimate that past earthquakes triggered fewer than half of the landslides in the past 1000 years. We find landslide frequency increases with mean annual precipitation but not with modeled peak ground acceleration or proximity to the megathrust. Our results agree with findings about other recent subduction zone earthquakes where relatively few deep-seated landslides were mapped and suggest that despite proximity to the megathrust, most deep-seated landslides in the Oregon Coast Range were triggered by rainfall.

Oregon↗
USGS2019

Quantitative coseismic and precipitation-induced landslide risk mapping for the country of Lebanon

Quantitative landslide risk assessment is a key step in creating appropriate land use policies. The forced migration of those displaced by recent events in Syria has highlighted the need for studies to guide humanitarian aid and resettlement policies. In 2011, armed conflict in the region precipitated the largest refugee crisis in a generation. Over 1.5 million displaced Syrians now reside in Lebanon, rapidly changing the population distribution in geomorphically-active areas of the country. We use a multi-step process to quantitatively assess the landslide risk profile of Lebanon throughout the ongoing Syrian conflict. First, mode-specific geotechnical models are utilized to assess the individual hazard contributions of a suite of triggering scenarios and types of landslides appropriate to the varied terrain of Lebanon. Second, vulnerability estimates and population data from the United Nations High Commissioner for Refugees (UNHCR) are combined to produce scenario-specific risk. Finally, risk data is aggregated to create a comprehensive landslide risk profile for Syrian refugees in Lebanon and compared to that of the pre-conflict Lebanese population.

Conference Paper↗
USGS2019

Risk at the margins: A natural hazards perspective on the Syrian refugee crisis in Lebanon

Quantitative landslide risk analysis is a key step in creating appropriate land use policies. The forced migration of those displaced by recent armed conflict in Syria has highlighted the need for studies to guide humanitarian aid and resettlement policies. Over 1.5 million displaced Syrians now reside in Lebanon, self-settling throughout the country through urban integration and informal encampment due to Lebanon's prohibition of formal refugee camps. The Syrian-Lebanon refugee crisis coincides with the recent reexamination of the established aid practice of camp-based resettlement, focused on issues of aid efficacy, security, and human dignity but lacking an environmental hazards perspective. In light of these issues, we quantitatively assess the landslide risk profile of Lebanon, finding a 75% increase in landslide risk since the start of the Syrian crisis. The risk is highest in the debris flow-prone mountains of central and northeastern Lebanon. Additionally, Syrian refugees settled in informal camps experience 9–11 times greater risk then urban populations due to sub-standard shelter, suggesting that urban rather than camp-based resettlement policies are preferable from an environmental-hazards perspective.

International Journal of Disaster Risk Reduction↗
USGS2008

New Orleans and Hurricane Katrina. IV: Orleans East Bank (Metro) protected basin

This paper addresses damage caused by Hurricane Katrina to the main Orleans East Bank protected basin. This basin represented the heart of New Orleans, and contained the main downtown area, the historic French Quarter, the Garden District, and the sprawling Lakefront and Canal Districts. Nearly half of the loss of life during this hurricane, and a similar fraction of the overall damages, occurred in this heavily populated basin. There are a number of important geotechnical lessons, as well as geo-forensic lessons, associated with the flooding of this basin. These include the difficulties associated with the creation and operation of regional-scale flood protection systems requiring federal and local cooperation and funding over prolonged periods of time. There are also a number of engineering and policy lessons regarding (1) the accuracy and reliability of current analytical methods; (2) the shortcomings and potential dangers involved in decisions that reduced short-term capital outlays in exchange for increased risk of potential system failures; (3) the difficulties associated with integrating local issues with a flood risk reduction project; and (4) the need to design and maintain levees as systems; with each of the many individual project elements being required to mesh seamlessly. These lessons are of interest and importance for similar flood protection systems throughout numerous other regions of the United States and the world. ?? 2008 ACSE.

Journal of Geotechnical and Geoenvironmental Engin↗
USGS2005

Geotechnical aspects of the January 2003 Tecoma'n, Mexico, earthquake

Ground failure was the most prominent geotechnical engineering feature of the 21 January 2003 M w 7.6 Tecoma´n earthquake. Ground failure impacted structures, industrial facilities, roads, water supply canals, and other critical infrastructure in the state of Colima and in parts of the neighboring states of Jalisco and Michoaca´n. Landslides and soil liquefaction were the most common type of ground failure, followed by seismic compression of unsaturated materials. Reinforced earth structures generally performed well during the earthquake, though some structures experienced permanent lateral deformations up to 10 cm. Different ground improvement techniques had been used to enhance the liquefaction resistance of several sites in the region, all of which performed well and exhibited no signs of damage or significant ground deformation. Earth dams in the region experienced some degree of permanent deformation but remained fully functional after the earthquake.

Earthquake Spectra↗