  We report on single-dish monitoring and extremely high angular resolution
observations of the flaring H2O megamaser in the Seyfert 2 galaxy Mrk 348. The
H2O line is redshifted by ~130 km/s with respect to the systemic velocity, is
very broad, with a FWHM of 130 km/s, and has no detectable high velocity
components within 1500 km/s on either side of the strong line. Monitoring
observations made with the Effelsberg 100m telescope show that the maser varies
significantly on timescales as short as one day and that the integrated line
flux is loosely correlated with the continuum flux. VLBA observations indicate
that the maser emission arises entirely from a region less than 0.25 pc in
extent, located toward a continuum component thought to be associated with the
receding jet. We also report on integrated flux monitoring with the VLA between
1.4 and 43 GHz, and VLBA continuum observations of the milliarcsecond scale
jets at 1.7, 8, 15, and 22 GHz. These observations have allowed us to
tentatively pinpoint the location of the core, and also show the ejection of a
new jet component during the current radio "flare."
