Continuous geoacoustic measurements with a three-component geophone made on the basis of magneto-elastic crystal ferromagnetic sensors and placed in a well (depth 2540 m) at Petropavlovsk-Kamchatsky carry out since August, 2000. Installation of geophone at depth about 1000 m allows to lower a level of a technogenic noise more than on two orders and also practically completely to eliminate influence meteorological factors on results of measurements of vertical components of a signal. According to 4-years observations results it has been noticed significant infringements and disappearance of a daily geoacoustic emission (GAE) pattern before all earthquakes with MLH≥ 5.0 occurred at distance less 300 km and earthquakes MLH≥ 5.5 in a zone R < 550 km from the point of observations. In addition to infringement of a daily pattern anomalies of geoacoustic level also have been consisted of bay-like changes daily average geoacoustic level coinciding by time with strongest earthquakes. Since May, 2003 continuous measurements of a natural electromagnetic field of the Earth in a band 30-1200 Hz by using of the underground electric antenna in length more than 1 km were carried out at the point of observations. Results of joint geoacoustic and electromagnetic measurements have been used for research of the physical nature of average level daily GAE pattern. Since April, 2004 at the point of observations the continuous automated monitoring of variations of water density in the well is executed by the developed original technique. Results of joint measurements by three kinds of geophysical monitoring allow better to understand the physical nature of observable anomalies, raise reliability of short-term precursors of earthquakes and reduce intervals of disturbing time for forecasts of earthquakes.