Abstract. Hydraulic fracturing, or fracking, is a borehole stimulation technique used
to enhance permeability in geological resource management, including the
extraction of shale gas. The process of hydraulic fracturing can induce
seismicity. The potential to induce seismicity is a topic of widespread
interest and public concern, particularly in the UK where seismicity induced by hydraulic fracturing has halted shale gas operations and triggered moratoria. Prior to 2018, there seemed to be a disconnect between the conclusions of expert groups about the risk of adverse impacts from
hydraulic-fracturing-induced seismicity and the reported level of public
concern about hydraulic fracturing induced seismicity. Furthermore, a range of terminology was used to describe the induced seismicity (including tremors,
earthquakes, seismic events, and micro-earthquakes) which could indicate the
level of perceived risk. Using the UK as a case study, we examine the
conclusions of expert-led public-facing reports on the risk (likelihood and
impact) of seismicity induced by hydraulic fracturing for shale gas
published between 2012 and 2018 and the terminology used in these reports.
We compare these to results from studies conducted in the same time period
that explored views of the UK public on hydraulic fracturing and
seismicity. Furthermore, we surveyed participants at professional and public
events on shale gas held throughout 2014 asking the same question that was
used in a series of surveys of the UK public in the period 2012–2016, i.e.
“do you associate shale gas with earthquakes?”. We asked our participants
to provide the reasoning for the answer they gave. By examining the
rationale provided for their answers, we find that an apparent polarisation
of views amongst experts was actually the result of different
interpretations of the language used to describe seismicity. Responses are
confounded by the ambiguity of the language around earthquake risk, magnitude, and
scale. We find that different terms are used in the survey responses to
describe earthquakes, often in an attempt to express the risk (magnitude,
shaking, and potential for adverse impact) presented by the earthquake, but that
these terms are poorly defined and ambiguous and do not translate into
everyday language usage. Such “bad language” around fracking has led to
challenges in understanding, perceiving, and communicating risks around
hydraulic-fracturing-induced seismicity. We call for multi-method approaches
to understand the perceived risks around geoenergy resources and suggest that
developing and adopting a shared language framework to describe earthquakes
would alleviate miscommunication and misperceptions. Our findings are
relevant to any applications that present – or are perceived to present – the
risk of induced seismicity. More broadly, our work is relevant to any topics
of public interest where language ambiguities muddle risk communication.
The importance of characterizing uncertainty in controversial geoscience applications: induced seismicity associated with hydraulic fracturing for shale gas in northwest England
