  We study a problem of distributed detection of a stationary point event in a
large extent wireless sensor network ($\wsn$), where the event influences the
observations of the sensors only in the vicinity of where it occurs. An event
occurs at an unknown time and at a random location in the coverage region (or
region of interest ($\ROI$)) of the $\wsn$. We consider a general sensing model
in which the effect of the event at a sensor node depends on the distance
between the event and the sensor node; in particular, in the Boolean sensing
model, all sensors in a disk of a given radius around the event are equally
affected. Following the prior work reported in
\cite{nikiforov95change_isolation},
\cite{nikiforov03lower-bound-for-det-isolation},
\cite{tartakovsky08multi-decision}, {\em the problem is formulated as that of
detecting the event and locating it to a subregion of the $\ROI$ as early as
possible under the constraints that the average run length to false alarm
($\tfa$) is bounded below by $\gamma$, and the probability of false isolation
($\pfi$) is bounded above by $\alpha$}, where $\gamma$ and $\alpha$ are target
performance requirements. In this setting, we propose distributed procedures
for event detection and isolation (namely $\mx$, $\all$, and $\hall$), based on
the local fusion of $\CUSUM$s at the sensors. For these procedures, we obtain
bounds on the maximum mean detection/isolation delay ($\add$), and on $\tfa$
and $\pfi$, and thus provide an upper bound on $\add$ as
$\min\{\gamma,1/\alpha\} \to \infty$. For the Boolean sensing model, we show
that an asymptotic upper bound on the maximum mean detection/isolation delay of
our distributed procedure scales with $\gamma$ and $\alpha$ in the same way as
the asymptotically optimal centralised procedure
\cite{nikiforov03lower-bound-for-det-isolation}.
