Array Observations of the 2012 Haida Gwaii Tsunami Using Cascadia Initiative Absolute and Differential Seafloor Pressure Gauges

Abstract

The purpose of this article is to test the ability of the seafloor pressure sensors utilized in the Cascadia Initiative (CI) experiment (Toomey et al. , 2014) to provide useful recordings of tsunamis, and to compare the performance of the different types of seafloor pressure sensors for long‐period recordings. These tests are performed through analysis of CI seafloor pressure recordings of the 2012 Haida Gwaii tsunami. Seafloor pressure measurements are a central part of tsunami warning systems. Deep‐ocean Assessment and Reporting of Tsunamis (DART) buoy systems, designed by National Oceanic and Atmospheric Administration (NOAA), are equipped with seafloor pressure sensors (also referred to as bottom pressure recorders [BPRs]), providing tsunami data in real time (Eble and Gonzalez, 1991; Gonzalez et al. , 1998; Bernard et al. , 2001; Meinig et al. , 2005; Titov et al. , 2005; Mofjeld, 2009; Rabinovich and Eble, 2015). The DART instruments are widely spaced in deep water (typically >2700 m) along coastal regions and near subduction zones. Cabled BPR arrays are becoming more common, such as the BPR array of NorthEast Pacific Time‐Series Undersea Networked Experiments (NEPTUNE)‐Canada ocean observatory (Thomson et al. , 2011), the Japan Agency for Marine‐Earth Science and Technology (JAMSTEC) BPR array (Baba et al. , 2004; Saito et al. , 2010), and the BPR array in the Cascadia basin (Rabinovich et al. , 2011). Observations of tsunamis have also been made serendipitously on pressure gauges accompanying a variety of nontsunami field programs (e.g., Drushka et al. , 2008; Lin et al. , 2015). In this study, we use seafloor pressure measurements from absolute pressure gauges (APGs), differential pressure gauges (DPGs), and DART BPRs to study the tsunami caused by the 2012 Haida Gwaii earthquake. The APG, used by the DART and increasingly in other oceanographic studies (Ito et al. , 2011; Chadwick et al. …