DOI: 10.7914/sn/yh_2017
title: Seismometer to Investigate Ice and Ocean Structure (SIIOS) Field Experiment

description: To investigate the viability of a seismic experiment on an Ocean Worlds lander mission, we are undertaking a series of analog field studies to develop operational techniques and quantify the science return of a Seismometer to Investigate Ice and Ocean Structure (SIIOS). Specifically, we aim to achieve the following objectives: 1) Demonstrate the ability of a small aperture seismic arrays in a “lander-like” configuration (using 3-4 devices) to discriminate between ice/ocean/bedrock layers in Earth's cryosphere, and record the influence of diurnal motion, as an analog to Ocean Worlds. 2) Demonstrate the improved resolution of a small aperture array over a single instrument for the detection and location of passive seismicity and noise sources in an Ocean Worlds analog environment. 3) Develop protocols and requirements for spacecraft onboard generation of data products that preserve science results while also being compatible with data downlink limitations typical for missions deployed in the outer solar system. 4) Determine the most effective types of passive seismic sources (e.g., ice cracking) for measuring ice and ocean structure. The first field validation experiment will take place for 2 weeks on an alpine glacier in central Alaska, in late summer (August) when the winter snow cover has melted and there is hard ice at the surface. Gulkana Glacier is located in the cold, and dry continental climate of the eastern Alaska Range. The purpose of going to Gulkana glacier is to collect a “lander-like” seismic dataset in a relevant environment that is accessible and logistically uncomplicated. This will provide the data necessary to begin implementing data reduction techniques that can be used during the following Antarctic field season. The second field campaign will take place at the Ross Ice Shelf (RIS), Antarctica’s largest ice shelf. RIS is a floating platform of ice above Ross Sea; the depths of the ice and ocean layers (hundreds of meters) , as well as the influence of diurnal tides, make RIS a more compelling Ocean World analog than Gulkana Glacier. The RIS field exercise site installation will begin in early October 2018 in coordination with the seasonal reopening of the South Pole traverse route and last nominally for two weeks. To reduce logistical complications, the second field validation test will occur in coordination with annual logistical efforts undertaken each year to construct a safe land route through the shear zone near McMurdo Station. We will be using a combination of PASSCAL equipment and Silicon Audio instruments which should be able to interface with Reftek-130 data loggers. Each of the stations will be collocated in a short aperture array of approximately 3 meters radius. At the center of the array we will deploy a short period and broadband station. Each arm of the array will have a Silicon Audio seismometer deployed alongside a 3-component geophone. The Gulkana experiment should record for approximately 2 weeks, the Ross Ice Shelf experiment will likely be deployed early in the 2018-2019 field season (October) and demobilized in January of 2019.