“…Nonlinear elastic effects arise in solids due to the presence of imperfections at the micro/mesoscopic scale, such as cracks or dislocations (Guyer & Johnson, 2009; Ostrovsky & Johnson, 2001). Understanding the origins of these nonlinear elastic effects is critical to numerous fields, from geophysics (Abeele et al., 2002; Delorey et al., 2021; Feng et al., 2018, 2022; Guyer & Johnson, 2009; Hillers et al., 2015; Johnson & Sutin, 2005; Johnson et al., 2004; Manogharan et al., 2021; McCall & Guyer, 1994; Pimienta et al., 2014; Renaud et al., 2012; Shokouhi et al., 2020; Tadavani et al., 2020; TenCate et al., 1996, 2016) and civil engineering (Abeele & De Visscher, 2000; Astorga et al., 2018; Bittner & Popovics, 2022; Kim et al., 2017; Lacouture et al., 2003; Payan et al., 2014; Shokouhi et al., 2017) to the non‐destructive evaluation of materials (Breazeale & Ford, 1965; Buck et al., 1978; Jin et al., 2020; Kim et al., 2006; Matlack et al., 2015; Williams et al., 2022). Elastic nonlinearity is particularly large in poorly consolidated or unconsolidated materials, where it arises from weak junctions between grains (Brunet et al., 2008; Guyer & Johnson, 1999, 2009; Jia et al., 2011; Johnson & Jia, 2005; Langlois & Jia, 2014; Renaud et al., 2012; Rivière et al., 2015; Yoritomo & Weaver, 2020a, 2020b, 2020c).…”