diff --git a/QtPyLoT.py b/QtPyLoT.py
index 1a0ff6d2..413d0d76 100755
--- a/QtPyLoT.py
+++ b/QtPyLoT.py
@@ -40,6 +40,7 @@ import numpy as np
 import subprocess
 from obspy import UTCDateTime
 
+from pylot.core.analysis.magnitude import calcsourcespec, calcMoMw
 from pylot.core.io.data import Data
 from pylot.core.io.inputs import FilterOptions, AutoPickParameter
 from pylot.core.pick.autopick import autopickevent
@@ -945,16 +946,31 @@ class MainWindow(QMainWindow):
             os.remove(phasepath)
 
         self.getData().applyEVTData(lt.read_location(locpath), type='event')
+        self.calc_magnitude()
 
     def calc_magnitude(self):
         e = self.getData().getEvtData()
+        settings = QSettings()
         if e.origins:
             o = e.origins[0]
+            mags = dict()
             for a in o.arrivals:
-                pid = a.pick_id
-                pick = pid.get_referred_object()
-                station = self.getStationID(pick.waveform_id.station_code)
+                pick = a.pick_id.get_referred_object()
+                station = pick.waveform_id.station_code
                 wf = self.getData().getWFData().select(station=station)
+                onset = pick.time
+                fninv = settings.value("inventoryFile", None)
+                if fninv is None:
+                    fninv = QFileDialog.getOpenFileName()
+                    ans = QMessageBox.question(self, self.tr("Make default..."),
+                               self.tr("New inventory filename set.\n" + \
+                                  "Do you want to make it the default value?"),
+                               QMessageBox.Yes | QMessageBox.No,
+                               QMessageBox.No)
+                    print(ans)
+                    settings.setValue("inventoryFile", fninv)
+                #w0, fc = calcsourcespec(wf, onset, )
+                #mags[station] =
             mag = None
             return mag
         else:
diff --git a/pylot/core/io/data.py b/pylot/core/io/data.py
index 1f4a6008..0477507a 100644
--- a/pylot/core/io/data.py
+++ b/pylot/core/io/data.py
@@ -10,7 +10,7 @@ from obspy.core.event import Event
 from obspy.io.xseed import Parser
 
 from pylot.core.io.phases import readPILOTEvent, picks_from_picksdict, \
-    picksdict_from_pilot
+    picksdict_from_pilot, merge_picks
 from pylot.core.util.errors import FormatError, OverwriteError
 from pylot.core.util.utils import fnConstructor, getGlobalTimes
 
@@ -454,9 +454,9 @@ class Data(object):
             if not self.isNew():
                 self.setEvtData(event)
             else:
-                # prevent overwriting uncertainty information
+                # prevent overwriting original pick information
                 picks =  copy.deepcopy(self.getEvtData().picks)
-                event.picks = picks
+                event = merge_picks(event, picks)
                 # apply event information from location
                 self.getEvtData().update(event)
 
diff --git a/pylot/core/io/phases.py b/pylot/core/io/phases.py
index 0de1d40a..bd255b34 100644
--- a/pylot/core/io/phases.py
+++ b/pylot/core/io/phases.py
@@ -527,3 +527,26 @@ def writephases(arrivals, fformat, filename):
                                                                                              Ao))
 
         fid.close()
+
+
+def merge_picks(event, picks):
+    """
+    takes an event object and a list of picks and searches for matching
+    entries by comparing station name and phase_hint and overwrites the time
+    and time_errors value of the event picks' with those from the picks
+    without changing the resource identifiers
+    :param event: `obspy.core.event.Event` object (e.g. from NLLoc output)
+    :param picks: list of `obspy.core.event.Pick` objects containing the
+    original time and time_errors values
+    :return: merged `obspy.core.event.Event` object
+    """
+    for pick in picks:
+        time = pick.time
+        err = pick.time_errors
+        phase = pick.phase_hint
+        station = pick.waveform_id.station_code
+        for p in event.picks:
+            if p.waveform_id.station_code == station and p.phase_hint == phase:
+                p.time, p.time_errors = time, err
+        del time, err, phase, station
+    return event
\ No newline at end of file